Immutable branch between MFD, Base, ACPI and DMA due for v4.3

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Merge tag 'ib-mfd-base-acpi-dma-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into acpi-pm

Pull MFD-related material including ACPI device power management
changes (in addition to MFD, driver core and DMA changes) for v4.3
from Lee Jones.

* tag 'ib-mfd-base-acpi-dma-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd:
  mfd: Add support for Intel Sunrisepoint LPSS devices
  dmaengine: add a driver for Intel integrated DMA 64-bit
  mfd: make mfd_remove_devices() iterate in reverse order
  driver core: implement device_for_each_child_reverse()
  klist: implement klist_prev()
  Driver core: wakeup the parent device before trying probe
  ACPI / PM: Attach ACPI power domain only once
  PM / QoS: Make it possible to expose device latency tolerance to userspace
This commit is contained in:
Rafael J. Wysocki 2015-07-29 23:49:22 +02:00
commit 5af310a8ee
23 changed files with 1964 additions and 17 deletions

View File

@ -1123,6 +1123,14 @@ int acpi_dev_pm_attach(struct device *dev, bool power_on)
if (dev->pm_domain)
return -EEXIST;
/*
* Only attach the power domain to the first device if the
* companion is shared by multiple. This is to prevent doing power
* management twice.
*/
if (!acpi_device_is_first_physical_node(adev, dev))
return -EBUSY;
acpi_add_pm_notifier(adev, dev, acpi_pm_notify_work_func);
dev->pm_domain = &acpi_general_pm_domain;
if (power_on) {

View File

@ -97,6 +97,8 @@ void acpi_device_add_finalize(struct acpi_device *device);
void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
bool acpi_device_is_present(struct acpi_device *adev);
bool acpi_device_is_battery(struct acpi_device *adev);
bool acpi_device_is_first_physical_node(struct acpi_device *adev,
const struct device *dev);
/* --------------------------------------------------------------------------
Power Resource

View File

@ -226,6 +226,35 @@ static int create_of_modalias(struct acpi_device *acpi_dev, char *modalias,
return len;
}
/**
* acpi_device_is_first_physical_node - Is given dev first physical node
* @adev: ACPI companion device
* @dev: Physical device to check
*
* Function checks if given @dev is the first physical devices attached to
* the ACPI companion device. This distinction is needed in some cases
* where the same companion device is shared between many physical devices.
*
* Note that the caller have to provide valid @adev pointer.
*/
bool acpi_device_is_first_physical_node(struct acpi_device *adev,
const struct device *dev)
{
bool ret = false;
mutex_lock(&adev->physical_node_lock);
if (!list_empty(&adev->physical_node_list)) {
const struct acpi_device_physical_node *node;
node = list_first_entry(&adev->physical_node_list,
struct acpi_device_physical_node, node);
ret = node->dev == dev;
}
mutex_unlock(&adev->physical_node_lock);
return ret;
}
/*
* acpi_companion_match() - Can we match via ACPI companion device
* @dev: Device in question
@ -250,7 +279,6 @@ static int create_of_modalias(struct acpi_device *acpi_dev, char *modalias,
static struct acpi_device *acpi_companion_match(const struct device *dev)
{
struct acpi_device *adev;
struct mutex *physical_node_lock;
adev = ACPI_COMPANION(dev);
if (!adev)
@ -259,21 +287,7 @@ static struct acpi_device *acpi_companion_match(const struct device *dev)
if (list_empty(&adev->pnp.ids))
return NULL;
physical_node_lock = &adev->physical_node_lock;
mutex_lock(physical_node_lock);
if (list_empty(&adev->physical_node_list)) {
adev = NULL;
} else {
const struct acpi_device_physical_node *node;
node = list_first_entry(&adev->physical_node_list,
struct acpi_device_physical_node, node);
if (node->dev != dev)
adev = NULL;
}
mutex_unlock(physical_node_lock);
return adev;
return acpi_device_is_first_physical_node(adev, dev) ? adev : NULL;
}
static int __acpi_device_uevent_modalias(struct acpi_device *adev,

View File

@ -1252,6 +1252,19 @@ void device_unregister(struct device *dev)
}
EXPORT_SYMBOL_GPL(device_unregister);
static struct device *prev_device(struct klist_iter *i)
{
struct klist_node *n = klist_prev(i);
struct device *dev = NULL;
struct device_private *p;
if (n) {
p = to_device_private_parent(n);
dev = p->device;
}
return dev;
}
static struct device *next_device(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
@ -1340,6 +1353,36 @@ int device_for_each_child(struct device *parent, void *data,
}
EXPORT_SYMBOL_GPL(device_for_each_child);
/**
* device_for_each_child_reverse - device child iterator in reversed order.
* @parent: parent struct device.
* @fn: function to be called for each device.
* @data: data for the callback.
*
* Iterate over @parent's child devices, and call @fn for each,
* passing it @data.
*
* We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value.
*/
int device_for_each_child_reverse(struct device *parent, void *data,
int (*fn)(struct device *dev, void *data))
{
struct klist_iter i;
struct device *child;
int error = 0;
if (!parent->p)
return 0;
klist_iter_init(&parent->p->klist_children, &i);
while ((child = prev_device(&i)) && !error)
error = fn(child, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
/**
* device_find_child - device iterator for locating a particular device.
* @parent: parent struct device

View File

@ -399,6 +399,8 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe);
*
* This function must be called with @dev lock held. When called for a
* USB interface, @dev->parent lock must be held as well.
*
* If the device has a parent, runtime-resume the parent before driver probing.
*/
int driver_probe_device(struct device_driver *drv, struct device *dev)
{
@ -410,10 +412,16 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
drv->bus->name, __func__, dev_name(dev), drv->name);
if (dev->parent)
pm_runtime_get_sync(dev->parent);
pm_runtime_barrier(dev);
ret = really_probe(dev, drv);
pm_request_idle(dev);
if (dev->parent)
pm_runtime_put(dev->parent);
return ret;
}
@ -507,11 +515,17 @@ static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
device_lock(dev);
if (dev->parent)
pm_runtime_get_sync(dev->parent);
bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
dev_dbg(dev, "async probe completed\n");
pm_request_idle(dev);
if (dev->parent)
pm_runtime_put(dev->parent);
device_unlock(dev);
put_device(dev);
@ -541,6 +555,9 @@ static int __device_attach(struct device *dev, bool allow_async)
.want_async = false,
};
if (dev->parent)
pm_runtime_get_sync(dev->parent);
ret = bus_for_each_drv(dev->bus, NULL, &data,
__device_attach_driver);
if (!ret && allow_async && data.have_async) {
@ -557,6 +574,9 @@ static int __device_attach(struct device *dev, bool allow_async)
} else {
pm_request_idle(dev);
}
if (dev->parent)
pm_runtime_put(dev->parent);
}
out_unlock:
device_unlock(dev);

View File

@ -73,6 +73,8 @@ extern int pm_qos_sysfs_add_resume_latency(struct device *dev);
extern void pm_qos_sysfs_remove_resume_latency(struct device *dev);
extern int pm_qos_sysfs_add_flags(struct device *dev);
extern void pm_qos_sysfs_remove_flags(struct device *dev);
extern int pm_qos_sysfs_add_latency_tolerance(struct device *dev);
extern void pm_qos_sysfs_remove_latency_tolerance(struct device *dev);
#else /* CONFIG_PM */

View File

@ -883,3 +883,40 @@ int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
mutex_unlock(&dev_pm_qos_mtx);
return ret;
}
/**
* dev_pm_qos_expose_latency_tolerance - Expose latency tolerance to userspace
* @dev: Device whose latency tolerance to expose
*/
int dev_pm_qos_expose_latency_tolerance(struct device *dev)
{
int ret;
if (!dev->power.set_latency_tolerance)
return -EINVAL;
mutex_lock(&dev_pm_qos_sysfs_mtx);
ret = pm_qos_sysfs_add_latency_tolerance(dev);
mutex_unlock(&dev_pm_qos_sysfs_mtx);
return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_tolerance);
/**
* dev_pm_qos_hide_latency_tolerance - Hide latency tolerance from userspace
* @dev: Device whose latency tolerance to hide
*/
void dev_pm_qos_hide_latency_tolerance(struct device *dev)
{
mutex_lock(&dev_pm_qos_sysfs_mtx);
pm_qos_sysfs_remove_latency_tolerance(dev);
mutex_unlock(&dev_pm_qos_sysfs_mtx);
/* Remove the request from user space now */
pm_runtime_get_sync(dev);
dev_pm_qos_update_user_latency_tolerance(dev,
PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT);
pm_runtime_put(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);

View File

@ -738,6 +738,17 @@ void pm_qos_sysfs_remove_flags(struct device *dev)
sysfs_unmerge_group(&dev->kobj, &pm_qos_flags_attr_group);
}
int pm_qos_sysfs_add_latency_tolerance(struct device *dev)
{
return sysfs_merge_group(&dev->kobj,
&pm_qos_latency_tolerance_attr_group);
}
void pm_qos_sysfs_remove_latency_tolerance(struct device *dev)
{
sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group);
}
void rpm_sysfs_remove(struct device *dev)
{
sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);

View File

@ -85,6 +85,14 @@ config INTEL_IOP_ADMA
help
Enable support for the Intel(R) IOP Series RAID engines.
config IDMA64
tristate "Intel integrated DMA 64-bit support"
select DMA_ENGINE
select DMA_VIRTUAL_CHANNELS
help
Enable DMA support for Intel Low Power Subsystem such as found on
Intel Skylake PCH.
source "drivers/dma/dw/Kconfig"
config AT_HDMAC

View File

@ -14,6 +14,7 @@ obj-$(CONFIG_HSU_DMA) += hsu/
obj-$(CONFIG_MPC512X_DMA) += mpc512x_dma.o
obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
obj-$(CONFIG_MV_XOR) += mv_xor.o
obj-$(CONFIG_IDMA64) += idma64.o
obj-$(CONFIG_DW_DMAC_CORE) += dw/
obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
obj-$(CONFIG_AT_XDMAC) += at_xdmac.o

710
drivers/dma/idma64.c Normal file
View File

@ -0,0 +1,710 @@
/*
* Core driver for the Intel integrated DMA 64-bit
*
* Copyright (C) 2015 Intel Corporation
* Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include "idma64.h"
/* Platform driver name */
#define DRV_NAME "idma64"
/* For now we support only two channels */
#define IDMA64_NR_CHAN 2
/* ---------------------------------------------------------------------- */
static struct device *chan2dev(struct dma_chan *chan)
{
return &chan->dev->device;
}
/* ---------------------------------------------------------------------- */
static void idma64_off(struct idma64 *idma64)
{
unsigned short count = 100;
dma_writel(idma64, CFG, 0);
channel_clear_bit(idma64, MASK(XFER), idma64->all_chan_mask);
channel_clear_bit(idma64, MASK(BLOCK), idma64->all_chan_mask);
channel_clear_bit(idma64, MASK(SRC_TRAN), idma64->all_chan_mask);
channel_clear_bit(idma64, MASK(DST_TRAN), idma64->all_chan_mask);
channel_clear_bit(idma64, MASK(ERROR), idma64->all_chan_mask);
do {
cpu_relax();
} while (dma_readl(idma64, CFG) & IDMA64_CFG_DMA_EN && --count);
}
static void idma64_on(struct idma64 *idma64)
{
dma_writel(idma64, CFG, IDMA64_CFG_DMA_EN);
}
/* ---------------------------------------------------------------------- */
static void idma64_chan_init(struct idma64 *idma64, struct idma64_chan *idma64c)
{
u32 cfghi = IDMA64C_CFGH_SRC_PER(1) | IDMA64C_CFGH_DST_PER(0);
u32 cfglo = 0;
/* Enforce FIFO drain when channel is suspended */
cfglo |= IDMA64C_CFGL_CH_DRAIN;
/* Set default burst alignment */
cfglo |= IDMA64C_CFGL_DST_BURST_ALIGN | IDMA64C_CFGL_SRC_BURST_ALIGN;
channel_writel(idma64c, CFG_LO, cfglo);
channel_writel(idma64c, CFG_HI, cfghi);
/* Enable interrupts */
channel_set_bit(idma64, MASK(XFER), idma64c->mask);
channel_set_bit(idma64, MASK(ERROR), idma64c->mask);
/*
* Enforce the controller to be turned on.
*
* The iDMA is turned off in ->probe() and looses context during system
* suspend / resume cycle. That's why we have to enable it each time we
* use it.
*/
idma64_on(idma64);
}
static void idma64_chan_stop(struct idma64 *idma64, struct idma64_chan *idma64c)
{
channel_clear_bit(idma64, CH_EN, idma64c->mask);
}
static void idma64_chan_start(struct idma64 *idma64, struct idma64_chan *idma64c)
{
struct idma64_desc *desc = idma64c->desc;
struct idma64_hw_desc *hw = &desc->hw[0];
channel_writeq(idma64c, SAR, 0);
channel_writeq(idma64c, DAR, 0);
channel_writel(idma64c, CTL_HI, IDMA64C_CTLH_BLOCK_TS(~0UL));
channel_writel(idma64c, CTL_LO, IDMA64C_CTLL_LLP_S_EN | IDMA64C_CTLL_LLP_D_EN);
channel_writeq(idma64c, LLP, hw->llp);
channel_set_bit(idma64, CH_EN, idma64c->mask);
}
static void idma64_stop_transfer(struct idma64_chan *idma64c)
{
struct idma64 *idma64 = to_idma64(idma64c->vchan.chan.device);
idma64_chan_stop(idma64, idma64c);
}
static void idma64_start_transfer(struct idma64_chan *idma64c)
{
struct idma64 *idma64 = to_idma64(idma64c->vchan.chan.device);
struct virt_dma_desc *vdesc;
/* Get the next descriptor */
vdesc = vchan_next_desc(&idma64c->vchan);
if (!vdesc) {
idma64c->desc = NULL;
return;
}
list_del(&vdesc->node);
idma64c->desc = to_idma64_desc(vdesc);
/* Configure the channel */
idma64_chan_init(idma64, idma64c);
/* Start the channel with a new descriptor */
idma64_chan_start(idma64, idma64c);
}
/* ---------------------------------------------------------------------- */
static void idma64_chan_irq(struct idma64 *idma64, unsigned short c,
u32 status_err, u32 status_xfer)
{
struct idma64_chan *idma64c = &idma64->chan[c];
struct idma64_desc *desc;
unsigned long flags;
spin_lock_irqsave(&idma64c->vchan.lock, flags);
desc = idma64c->desc;
if (desc) {
if (status_err & (1 << c)) {
dma_writel(idma64, CLEAR(ERROR), idma64c->mask);
desc->status = DMA_ERROR;
} else if (status_xfer & (1 << c)) {
dma_writel(idma64, CLEAR(XFER), idma64c->mask);
desc->status = DMA_COMPLETE;
vchan_cookie_complete(&desc->vdesc);
idma64_start_transfer(idma64c);
}
/* idma64_start_transfer() updates idma64c->desc */
if (idma64c->desc == NULL || desc->status == DMA_ERROR)
idma64_stop_transfer(idma64c);
}
spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
}
static irqreturn_t idma64_irq(int irq, void *dev)
{
struct idma64 *idma64 = dev;
u32 status = dma_readl(idma64, STATUS_INT);
u32 status_xfer;
u32 status_err;
unsigned short i;
dev_vdbg(idma64->dma.dev, "%s: status=%#x\n", __func__, status);
/* Check if we have any interrupt from the DMA controller */
if (!status)
return IRQ_NONE;
/* Disable interrupts */
channel_clear_bit(idma64, MASK(XFER), idma64->all_chan_mask);
channel_clear_bit(idma64, MASK(ERROR), idma64->all_chan_mask);
status_xfer = dma_readl(idma64, RAW(XFER));
status_err = dma_readl(idma64, RAW(ERROR));
for (i = 0; i < idma64->dma.chancnt; i++)
idma64_chan_irq(idma64, i, status_err, status_xfer);
/* Re-enable interrupts */
channel_set_bit(idma64, MASK(XFER), idma64->all_chan_mask);
channel_set_bit(idma64, MASK(ERROR), idma64->all_chan_mask);
return IRQ_HANDLED;
}
/* ---------------------------------------------------------------------- */
static struct idma64_desc *idma64_alloc_desc(unsigned int ndesc)
{
struct idma64_desc *desc;
desc = kzalloc(sizeof(*desc), GFP_NOWAIT);
if (!desc)
return NULL;
desc->hw = kcalloc(ndesc, sizeof(*desc->hw), GFP_NOWAIT);
if (!desc->hw) {
kfree(desc);
return NULL;
}
return desc;
}
static void idma64_desc_free(struct idma64_chan *idma64c,
struct idma64_desc *desc)
{
struct idma64_hw_desc *hw;
if (desc->ndesc) {
unsigned int i = desc->ndesc;
do {
hw = &desc->hw[--i];
dma_pool_free(idma64c->pool, hw->lli, hw->llp);
} while (i);
}
kfree(desc->hw);
kfree(desc);
}
static void idma64_vdesc_free(struct virt_dma_desc *vdesc)
{
struct idma64_chan *idma64c = to_idma64_chan(vdesc->tx.chan);
idma64_desc_free(idma64c, to_idma64_desc(vdesc));
}
static u64 idma64_hw_desc_fill(struct idma64_hw_desc *hw,
struct dma_slave_config *config,
enum dma_transfer_direction direction, u64 llp)
{
struct idma64_lli *lli = hw->lli;
u64 sar, dar;
u32 ctlhi = IDMA64C_CTLH_BLOCK_TS(hw->len);
u32 ctllo = IDMA64C_CTLL_LLP_S_EN | IDMA64C_CTLL_LLP_D_EN;
u32 src_width, dst_width;
if (direction == DMA_MEM_TO_DEV) {
sar = hw->phys;
dar = config->dst_addr;
ctllo |= IDMA64C_CTLL_DST_FIX | IDMA64C_CTLL_SRC_INC |
IDMA64C_CTLL_FC_M2P;
src_width = min_t(u32, 2, __fls(sar | hw->len));
dst_width = __fls(config->dst_addr_width);
} else { /* DMA_DEV_TO_MEM */
sar = config->src_addr;
dar = hw->phys;
ctllo |= IDMA64C_CTLL_DST_INC | IDMA64C_CTLL_SRC_FIX |
IDMA64C_CTLL_FC_P2M;
src_width = __fls(config->src_addr_width);
dst_width = min_t(u32, 2, __fls(dar | hw->len));
}
lli->sar = sar;
lli->dar = dar;
lli->ctlhi = ctlhi;
lli->ctllo = ctllo |
IDMA64C_CTLL_SRC_MSIZE(config->src_maxburst) |
IDMA64C_CTLL_DST_MSIZE(config->dst_maxburst) |
IDMA64C_CTLL_DST_WIDTH(dst_width) |
IDMA64C_CTLL_SRC_WIDTH(src_width);
lli->llp = llp;
return hw->llp;
}
static void idma64_desc_fill(struct idma64_chan *idma64c,
struct idma64_desc *desc)
{
struct dma_slave_config *config = &idma64c->config;
struct idma64_hw_desc *hw = &desc->hw[desc->ndesc - 1];
struct idma64_lli *lli = hw->lli;
u64 llp = 0;
unsigned int i = desc->ndesc;
/* Fill the hardware descriptors and link them to a list */
do {
hw = &desc->hw[--i];
llp = idma64_hw_desc_fill(hw, config, desc->direction, llp);
desc->length += hw->len;
} while (i);
/* Trigger interrupt after last block */
lli->ctllo |= IDMA64C_CTLL_INT_EN;
}
static struct dma_async_tx_descriptor *idma64_prep_slave_sg(
struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction direction,
unsigned long flags, void *context)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
struct idma64_desc *desc;
struct scatterlist *sg;
unsigned int i;
desc = idma64_alloc_desc(sg_len);
if (!desc)
return NULL;
for_each_sg(sgl, sg, sg_len, i) {
struct idma64_hw_desc *hw = &desc->hw[i];
/* Allocate DMA capable memory for hardware descriptor */
hw->lli = dma_pool_alloc(idma64c->pool, GFP_NOWAIT, &hw->llp);
if (!hw->lli) {
desc->ndesc = i;
idma64_desc_free(idma64c, desc);
return NULL;
}
hw->phys = sg_dma_address(sg);
hw->len = sg_dma_len(sg);
}
desc->ndesc = sg_len;
desc->direction = direction;
desc->status = DMA_IN_PROGRESS;
idma64_desc_fill(idma64c, desc);
return vchan_tx_prep(&idma64c->vchan, &desc->vdesc, flags);
}
static void idma64_issue_pending(struct dma_chan *chan)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
unsigned long flags;
spin_lock_irqsave(&idma64c->vchan.lock, flags);
if (vchan_issue_pending(&idma64c->vchan) && !idma64c->desc)
idma64_start_transfer(idma64c);
spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
}
static size_t idma64_active_desc_size(struct idma64_chan *idma64c)
{
struct idma64_desc *desc = idma64c->desc;
struct idma64_hw_desc *hw;
size_t bytes = desc->length;
u64 llp;
u32 ctlhi;
unsigned int i = 0;
llp = channel_readq(idma64c, LLP);
do {
hw = &desc->hw[i];
} while ((hw->llp != llp) && (++i < desc->ndesc));
if (!i)
return bytes;
do {
bytes -= desc->hw[--i].len;
} while (i);
ctlhi = channel_readl(idma64c, CTL_HI);
return bytes - IDMA64C_CTLH_BLOCK_TS(ctlhi);
}
static enum dma_status idma64_tx_status(struct dma_chan *chan,
dma_cookie_t cookie, struct dma_tx_state *state)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
struct virt_dma_desc *vdesc;
enum dma_status status;
size_t bytes;
unsigned long flags;
status = dma_cookie_status(chan, cookie, state);
if (status == DMA_COMPLETE)
return status;
spin_lock_irqsave(&idma64c->vchan.lock, flags);
vdesc = vchan_find_desc(&idma64c->vchan, cookie);
if (idma64c->desc && cookie == idma64c->desc->vdesc.tx.cookie) {
bytes = idma64_active_desc_size(idma64c);
dma_set_residue(state, bytes);
status = idma64c->desc->status;
} else if (vdesc) {
bytes = to_idma64_desc(vdesc)->length;
dma_set_residue(state, bytes);
}
spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
return status;
}
static void convert_burst(u32 *maxburst)
{
if (*maxburst)
*maxburst = __fls(*maxburst);
else
*maxburst = 0;
}
static int idma64_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
/* Check if chan will be configured for slave transfers */
if (!is_slave_direction(config->direction))
return -EINVAL;
memcpy(&idma64c->config, config, sizeof(idma64c->config));
convert_burst(&idma64c->config.src_maxburst);
convert_burst(&idma64c->config.dst_maxburst);
return 0;
}
static void idma64_chan_deactivate(struct idma64_chan *idma64c)
{
unsigned short count = 100;
u32 cfglo;
cfglo = channel_readl(idma64c, CFG_LO);
channel_writel(idma64c, CFG_LO, cfglo | IDMA64C_CFGL_CH_SUSP);
do {
udelay(1);
cfglo = channel_readl(idma64c, CFG_LO);
} while (!(cfglo & IDMA64C_CFGL_FIFO_EMPTY) && --count);
}
static void idma64_chan_activate(struct idma64_chan *idma64c)
{
u32 cfglo;
cfglo = channel_readl(idma64c, CFG_LO);
channel_writel(idma64c, CFG_LO, cfglo & ~IDMA64C_CFGL_CH_SUSP);
}
static int idma64_pause(struct dma_chan *chan)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
unsigned long flags;
spin_lock_irqsave(&idma64c->vchan.lock, flags);
if (idma64c->desc && idma64c->desc->status == DMA_IN_PROGRESS) {
idma64_chan_deactivate(idma64c);
idma64c->desc->status = DMA_PAUSED;
}
spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
return 0;
}
static int idma64_resume(struct dma_chan *chan)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
unsigned long flags;
spin_lock_irqsave(&idma64c->vchan.lock, flags);
if (idma64c->desc && idma64c->desc->status == DMA_PAUSED) {
idma64c->desc->status = DMA_IN_PROGRESS;
idma64_chan_activate(idma64c);
}
spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
return 0;
}
static int idma64_terminate_all(struct dma_chan *chan)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
unsigned long flags;
LIST_HEAD(head);
spin_lock_irqsave(&idma64c->vchan.lock, flags);
idma64_chan_deactivate(idma64c);
idma64_stop_transfer(idma64c);
if (idma64c->desc) {
idma64_vdesc_free(&idma64c->desc->vdesc);
idma64c->desc = NULL;
}
vchan_get_all_descriptors(&idma64c->vchan, &head);
spin_unlock_irqrestore(&idma64c->vchan.lock, flags);
vchan_dma_desc_free_list(&idma64c->vchan, &head);
return 0;
}
static int idma64_alloc_chan_resources(struct dma_chan *chan)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
/* Create a pool of consistent memory blocks for hardware descriptors */
idma64c->pool = dma_pool_create(dev_name(chan2dev(chan)),
chan->device->dev,
sizeof(struct idma64_lli), 8, 0);
if (!idma64c->pool) {
dev_err(chan2dev(chan), "No memory for descriptors\n");
return -ENOMEM;
}
return 0;
}
static void idma64_free_chan_resources(struct dma_chan *chan)
{
struct idma64_chan *idma64c = to_idma64_chan(chan);
vchan_free_chan_resources(to_virt_chan(chan));
dma_pool_destroy(idma64c->pool);
idma64c->pool = NULL;
}
/* ---------------------------------------------------------------------- */
#define IDMA64_BUSWIDTHS \
BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
static int idma64_probe(struct idma64_chip *chip)
{
struct idma64 *idma64;
unsigned short nr_chan = IDMA64_NR_CHAN;
unsigned short i;
int ret;
idma64 = devm_kzalloc(chip->dev, sizeof(*idma64), GFP_KERNEL);
if (!idma64)
return -ENOMEM;
idma64->regs = chip->regs;
chip->idma64 = idma64;
idma64->chan = devm_kcalloc(chip->dev, nr_chan, sizeof(*idma64->chan),
GFP_KERNEL);
if (!idma64->chan)
return -ENOMEM;
idma64->all_chan_mask = (1 << nr_chan) - 1;
/* Turn off iDMA controller */
idma64_off(idma64);
ret = devm_request_irq(chip->dev, chip->irq, idma64_irq, IRQF_SHARED,
dev_name(chip->dev), idma64);
if (ret)
return ret;
INIT_LIST_HEAD(&idma64->dma.channels);
for (i = 0; i < nr_chan; i++) {
struct idma64_chan *idma64c = &idma64->chan[i];
idma64c->vchan.desc_free = idma64_vdesc_free;
vchan_init(&idma64c->vchan, &idma64->dma);
idma64c->regs = idma64->regs + i * IDMA64_CH_LENGTH;
idma64c->mask = BIT(i);
}
dma_cap_set(DMA_SLAVE, idma64->dma.cap_mask);
dma_cap_set(DMA_PRIVATE, idma64->dma.cap_mask);
idma64->dma.device_alloc_chan_resources = idma64_alloc_chan_resources;
idma64->dma.device_free_chan_resources = idma64_free_chan_resources;
idma64->dma.device_prep_slave_sg = idma64_prep_slave_sg;
idma64->dma.device_issue_pending = idma64_issue_pending;
idma64->dma.device_tx_status = idma64_tx_status;
idma64->dma.device_config = idma64_slave_config;
idma64->dma.device_pause = idma64_pause;
idma64->dma.device_resume = idma64_resume;
idma64->dma.device_terminate_all = idma64_terminate_all;
idma64->dma.src_addr_widths = IDMA64_BUSWIDTHS;
idma64->dma.dst_addr_widths = IDMA64_BUSWIDTHS;
idma64->dma.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
idma64->dma.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
idma64->dma.dev = chip->dev;
ret = dma_async_device_register(&idma64->dma);
if (ret)
return ret;
dev_info(chip->dev, "Found Intel integrated DMA 64-bit\n");
return 0;
}
static int idma64_remove(struct idma64_chip *chip)
{
struct idma64 *idma64 = chip->idma64;
unsigned short i;
dma_async_device_unregister(&idma64->dma);
/*
* Explicitly call devm_request_irq() to avoid the side effects with
* the scheduled tasklets.
*/
devm_free_irq(chip->dev, chip->irq, idma64);
for (i = 0; i < idma64->dma.chancnt; i++) {
struct idma64_chan *idma64c = &idma64->chan[i];
tasklet_kill(&idma64c->vchan.task);
}
return 0;
}
/* ---------------------------------------------------------------------- */
static int idma64_platform_probe(struct platform_device *pdev)
{
struct idma64_chip *chip;
struct device *dev = &pdev->dev;
struct resource *mem;
int ret;
chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->irq = platform_get_irq(pdev, 0);
if (chip->irq < 0)
return chip->irq;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
chip->regs = devm_ioremap_resource(dev, mem);
if (IS_ERR(chip->regs))
return PTR_ERR(chip->regs);
ret = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
if (ret)
return ret;
chip->dev = dev;
ret = idma64_probe(chip);
if (ret)
return ret;
platform_set_drvdata(pdev, chip);
return 0;
}
static int idma64_platform_remove(struct platform_device *pdev)
{
struct idma64_chip *chip = platform_get_drvdata(pdev);
return idma64_remove(chip);
}
#ifdef CONFIG_PM_SLEEP
static int idma64_pm_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct idma64_chip *chip = platform_get_drvdata(pdev);
idma64_off(chip->idma64);
return 0;
}
static int idma64_pm_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct idma64_chip *chip = platform_get_drvdata(pdev);
idma64_on(chip->idma64);
return 0;
}
#endif /* CONFIG_PM_SLEEP */
static const struct dev_pm_ops idma64_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(idma64_pm_suspend, idma64_pm_resume)
};
static struct platform_driver idma64_platform_driver = {
.probe = idma64_platform_probe,
.remove = idma64_platform_remove,
.driver = {
.name = DRV_NAME,
.pm = &idma64_dev_pm_ops,
},
};
module_platform_driver(idma64_platform_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("iDMA64 core driver");
MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_ALIAS("platform:" DRV_NAME);

233
drivers/dma/idma64.h Normal file
View File

@ -0,0 +1,233 @@
/*
* Driver for the Intel integrated DMA 64-bit
*
* Copyright (C) 2015 Intel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __DMA_IDMA64_H__
#define __DMA_IDMA64_H__
#include <linux/device.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include "virt-dma.h"
/* Channel registers */
#define IDMA64_CH_SAR 0x00 /* Source Address Register */
#define IDMA64_CH_DAR 0x08 /* Destination Address Register */
#define IDMA64_CH_LLP 0x10 /* Linked List Pointer */
#define IDMA64_CH_CTL_LO 0x18 /* Control Register Low */
#define IDMA64_CH_CTL_HI 0x1c /* Control Register High */
#define IDMA64_CH_SSTAT 0x20
#define IDMA64_CH_DSTAT 0x28
#define IDMA64_CH_SSTATAR 0x30
#define IDMA64_CH_DSTATAR 0x38
#define IDMA64_CH_CFG_LO 0x40 /* Configuration Register Low */
#define IDMA64_CH_CFG_HI 0x44 /* Configuration Register High */
#define IDMA64_CH_SGR 0x48
#define IDMA64_CH_DSR 0x50
#define IDMA64_CH_LENGTH 0x58
/* Bitfields in CTL_LO */
#define IDMA64C_CTLL_INT_EN (1 << 0) /* irqs enabled? */
#define IDMA64C_CTLL_DST_WIDTH(x) ((x) << 1) /* bytes per element */
#define IDMA64C_CTLL_SRC_WIDTH(x) ((x) << 4)
#define IDMA64C_CTLL_DST_INC (0 << 8) /* DAR update/not */
#define IDMA64C_CTLL_DST_FIX (1 << 8)
#define IDMA64C_CTLL_SRC_INC (0 << 10) /* SAR update/not */
#define IDMA64C_CTLL_SRC_FIX (1 << 10)
#define IDMA64C_CTLL_DST_MSIZE(x) ((x) << 11) /* burst, #elements */
#define IDMA64C_CTLL_SRC_MSIZE(x) ((x) << 14)
#define IDMA64C_CTLL_FC_M2P (1 << 20) /* mem-to-periph */
#define IDMA64C_CTLL_FC_P2M (2 << 20) /* periph-to-mem */
#define IDMA64C_CTLL_LLP_D_EN (1 << 27) /* dest block chain */
#define IDMA64C_CTLL_LLP_S_EN (1 << 28) /* src block chain */
/* Bitfields in CTL_HI */
#define IDMA64C_CTLH_BLOCK_TS(x) ((x) & ((1 << 17) - 1))
#define IDMA64C_CTLH_DONE (1 << 17)
/* Bitfields in CFG_LO */
#define IDMA64C_CFGL_DST_BURST_ALIGN (1 << 0) /* dst burst align */
#define IDMA64C_CFGL_SRC_BURST_ALIGN (1 << 1) /* src burst align */
#define IDMA64C_CFGL_CH_SUSP (1 << 8)
#define IDMA64C_CFGL_FIFO_EMPTY (1 << 9)
#define IDMA64C_CFGL_CH_DRAIN (1 << 10) /* drain FIFO */
#define IDMA64C_CFGL_DST_OPT_BL (1 << 20) /* optimize dst burst length */
#define IDMA64C_CFGL_SRC_OPT_BL (1 << 21) /* optimize src burst length */
/* Bitfields in CFG_HI */
#define IDMA64C_CFGH_SRC_PER(x) ((x) << 0) /* src peripheral */
#define IDMA64C_CFGH_DST_PER(x) ((x) << 4) /* dst peripheral */
#define IDMA64C_CFGH_RD_ISSUE_THD(x) ((x) << 8)
#define IDMA64C_CFGH_RW_ISSUE_THD(x) ((x) << 18)
/* Interrupt registers */
#define IDMA64_INT_XFER 0x00
#define IDMA64_INT_BLOCK 0x08
#define IDMA64_INT_SRC_TRAN 0x10
#define IDMA64_INT_DST_TRAN 0x18
#define IDMA64_INT_ERROR 0x20
#define IDMA64_RAW(x) (0x2c0 + IDMA64_INT_##x) /* r */
#define IDMA64_STATUS(x) (0x2e8 + IDMA64_INT_##x) /* r (raw & mask) */
#define IDMA64_MASK(x) (0x310 + IDMA64_INT_##x) /* rw (set = irq enabled) */
#define IDMA64_CLEAR(x) (0x338 + IDMA64_INT_##x) /* w (ack, affects "raw") */
/* Common registers */
#define IDMA64_STATUS_INT 0x360 /* r */
#define IDMA64_CFG 0x398
#define IDMA64_CH_EN 0x3a0
/* Bitfields in CFG */
#define IDMA64_CFG_DMA_EN (1 << 0)
/* Hardware descriptor for Linked LIst transfers */
struct idma64_lli {
u64 sar;
u64 dar;
u64 llp;
u32 ctllo;
u32 ctlhi;
u32 sstat;
u32 dstat;
};
struct idma64_hw_desc {
struct idma64_lli *lli;
dma_addr_t llp;
dma_addr_t phys;
unsigned int len;
};
struct idma64_desc {
struct virt_dma_desc vdesc;
enum dma_transfer_direction direction;
struct idma64_hw_desc *hw;
unsigned int ndesc;
size_t length;
enum dma_status status;
};
static inline struct idma64_desc *to_idma64_desc(struct virt_dma_desc *vdesc)
{
return container_of(vdesc, struct idma64_desc, vdesc);
}
struct idma64_chan {
struct virt_dma_chan vchan;
void __iomem *regs;
/* hardware configuration */
enum dma_transfer_direction direction;
unsigned int mask;
struct dma_slave_config config;
void *pool;
struct idma64_desc *desc;
};
static inline struct idma64_chan *to_idma64_chan(struct dma_chan *chan)
{
return container_of(chan, struct idma64_chan, vchan.chan);
}
#define channel_set_bit(idma64, reg, mask) \
dma_writel(idma64, reg, ((mask) << 8) | (mask))
#define channel_clear_bit(idma64, reg, mask) \
dma_writel(idma64, reg, ((mask) << 8) | 0)
static inline u32 idma64c_readl(struct idma64_chan *idma64c, int offset)
{
return readl(idma64c->regs + offset);
}
static inline void idma64c_writel(struct idma64_chan *idma64c, int offset,
u32 value)
{
writel(value, idma64c->regs + offset);
}
#define channel_readl(idma64c, reg) \
idma64c_readl(idma64c, IDMA64_CH_##reg)
#define channel_writel(idma64c, reg, value) \
idma64c_writel(idma64c, IDMA64_CH_##reg, (value))
static inline u64 idma64c_readq(struct idma64_chan *idma64c, int offset)
{
u64 l, h;
l = idma64c_readl(idma64c, offset);
h = idma64c_readl(idma64c, offset + 4);
return l | (h << 32);
}
static inline void idma64c_writeq(struct idma64_chan *idma64c, int offset,
u64 value)
{
idma64c_writel(idma64c, offset, value);
idma64c_writel(idma64c, offset + 4, value >> 32);
}
#define channel_readq(idma64c, reg) \
idma64c_readq(idma64c, IDMA64_CH_##reg)
#define channel_writeq(idma64c, reg, value) \
idma64c_writeq(idma64c, IDMA64_CH_##reg, (value))
struct idma64 {
struct dma_device dma;
void __iomem *regs;
/* channels */
unsigned short all_chan_mask;
struct idma64_chan *chan;
};
static inline struct idma64 *to_idma64(struct dma_device *ddev)
{
return container_of(ddev, struct idma64, dma);
}
static inline u32 idma64_readl(struct idma64 *idma64, int offset)
{
return readl(idma64->regs + offset);
}
static inline void idma64_writel(struct idma64 *idma64, int offset, u32 value)
{
writel(value, idma64->regs + offset);
}
#define dma_readl(idma64, reg) \
idma64_readl(idma64, IDMA64_##reg)
#define dma_writel(idma64, reg, value) \
idma64_writel(idma64, IDMA64_##reg, (value))
/**
* struct idma64_chip - representation of DesignWare DMA controller hardware
* @dev: struct device of the DMA controller
* @irq: irq line
* @regs: memory mapped I/O space
* @idma64: struct idma64 that is filed by idma64_probe()
*/
struct idma64_chip {
struct device *dev;
int irq;
void __iomem *regs;
struct idma64 *idma64;
};
#endif /* __DMA_IDMA64_H__ */

View File

@ -328,6 +328,29 @@ config INTEL_SOC_PMIC
thermal, charger and related power management functions
on these systems.
config MFD_INTEL_LPSS
tristate
select COMMON_CLK
select MFD_CORE
config MFD_INTEL_LPSS_ACPI
tristate "Intel Low Power Subsystem support in ACPI mode"
select MFD_INTEL_LPSS
depends on X86 && ACPI
help
This driver supports Intel Low Power Subsystem (LPSS) devices such as
I2C, SPI and HS-UART starting from Intel Sunrisepoint (Intel Skylake
PCH) in ACPI mode.
config MFD_INTEL_LPSS_PCI
tristate "Intel Low Power Subsystem support in PCI mode"
select MFD_INTEL_LPSS
depends on X86 && PCI
help
This driver supports Intel Low Power Subsystem (LPSS) devices such as
I2C, SPI and HS-UART starting from Intel Sunrisepoint (Intel Skylake
PCH) in PCI mode.
config MFD_INTEL_MSIC
bool "Intel MSIC"
depends on INTEL_SCU_IPC

View File

@ -161,6 +161,9 @@ obj-$(CONFIG_TPS65911_COMPARATOR) += tps65911-comparator.o
obj-$(CONFIG_MFD_TPS65090) += tps65090.o
obj-$(CONFIG_MFD_AAT2870_CORE) += aat2870-core.o
obj-$(CONFIG_MFD_ATMEL_HLCDC) += atmel-hlcdc.o
obj-$(CONFIG_MFD_INTEL_LPSS) += intel-lpss.o
obj-$(CONFIG_MFD_INTEL_LPSS_PCI) += intel-lpss-pci.o
obj-$(CONFIG_MFD_INTEL_LPSS_ACPI) += intel-lpss-acpi.o
obj-$(CONFIG_MFD_INTEL_MSIC) += intel_msic.o
obj-$(CONFIG_MFD_PALMAS) += palmas.o
obj-$(CONFIG_MFD_VIPERBOARD) += viperboard.o

View File

@ -0,0 +1,84 @@
/*
* Intel LPSS ACPI support.
*
* Copyright (C) 2015, Intel Corporation
*
* Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
* Mika Westerberg <mika.westerberg@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/acpi.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/platform_device.h>
#include "intel-lpss.h"
static const struct intel_lpss_platform_info spt_info = {
.clk_rate = 120000000,
};
static const struct acpi_device_id intel_lpss_acpi_ids[] = {
/* SPT */
{ "INT3446", (kernel_ulong_t)&spt_info },
{ "INT3447", (kernel_ulong_t)&spt_info },
{ }
};
MODULE_DEVICE_TABLE(acpi, intel_lpss_acpi_ids);
static int intel_lpss_acpi_probe(struct platform_device *pdev)
{
struct intel_lpss_platform_info *info;
const struct acpi_device_id *id;
id = acpi_match_device(intel_lpss_acpi_ids, &pdev->dev);
if (!id)
return -ENODEV;
info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
GFP_KERNEL);
if (!info)
return -ENOMEM;
info->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
info->irq = platform_get_irq(pdev, 0);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
return intel_lpss_probe(&pdev->dev, info);
}
static int intel_lpss_acpi_remove(struct platform_device *pdev)
{
intel_lpss_remove(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return 0;
}
static INTEL_LPSS_PM_OPS(intel_lpss_acpi_pm_ops);
static struct platform_driver intel_lpss_acpi_driver = {
.probe = intel_lpss_acpi_probe,
.remove = intel_lpss_acpi_remove,
.driver = {
.name = "intel-lpss",
.acpi_match_table = intel_lpss_acpi_ids,
.pm = &intel_lpss_acpi_pm_ops,
},
};
module_platform_driver(intel_lpss_acpi_driver);
MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_DESCRIPTION("Intel LPSS ACPI driver");
MODULE_LICENSE("GPL v2");

View File

@ -0,0 +1,113 @@
/*
* Intel LPSS PCI support.
*
* Copyright (C) 2015, Intel Corporation
*
* Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
* Mika Westerberg <mika.westerberg@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include "intel-lpss.h"
static int intel_lpss_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *id)
{
struct intel_lpss_platform_info *info;
int ret;
ret = pcim_enable_device(pdev);
if (ret)
return ret;
info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
GFP_KERNEL);
if (!info)
return -ENOMEM;
info->mem = &pdev->resource[0];
info->irq = pdev->irq;
/* Probably it is enough to set this for iDMA capable devices only */
pci_set_master(pdev);
ret = intel_lpss_probe(&pdev->dev, info);
if (ret)
return ret;
pm_runtime_put(&pdev->dev);
pm_runtime_allow(&pdev->dev);
return 0;
}
static void intel_lpss_pci_remove(struct pci_dev *pdev)
{
pm_runtime_forbid(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
intel_lpss_remove(&pdev->dev);
}
static INTEL_LPSS_PM_OPS(intel_lpss_pci_pm_ops);
static const struct intel_lpss_platform_info spt_info = {
.clk_rate = 120000000,
};
static const struct intel_lpss_platform_info spt_uart_info = {
.clk_rate = 120000000,
.clk_con_id = "baudclk",
};
static const struct pci_device_id intel_lpss_pci_ids[] = {
/* SPT-LP */
{ PCI_VDEVICE(INTEL, 0x9d27), (kernel_ulong_t)&spt_uart_info },
{ PCI_VDEVICE(INTEL, 0x9d28), (kernel_ulong_t)&spt_uart_info },
{ PCI_VDEVICE(INTEL, 0x9d29), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d2a), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0x9d66), (kernel_ulong_t)&spt_uart_info },
/* SPT-H */
{ PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info },
{ PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info },
{ PCI_VDEVICE(INTEL, 0xa129), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0xa12a), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_info },
{ PCI_VDEVICE(INTEL, 0xa166), (kernel_ulong_t)&spt_uart_info },
{ }
};
MODULE_DEVICE_TABLE(pci, intel_lpss_pci_ids);
static struct pci_driver intel_lpss_pci_driver = {
.name = "intel-lpss",
.id_table = intel_lpss_pci_ids,
.probe = intel_lpss_pci_probe,
.remove = intel_lpss_pci_remove,
.driver = {
.pm = &intel_lpss_pci_pm_ops,
},
};
module_pci_driver(intel_lpss_pci_driver);
MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_DESCRIPTION("Intel LPSS PCI driver");
MODULE_LICENSE("GPL v2");

524
drivers/mfd/intel-lpss.c Normal file
View File

@ -0,0 +1,524 @@
/*
* Intel Sunrisepoint LPSS core support.
*
* Copyright (C) 2015, Intel Corporation
*
* Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
* Mika Westerberg <mika.westerberg@linux.intel.com>
* Heikki Krogerus <heikki.krogerus@linux.intel.com>
* Jarkko Nikula <jarkko.nikula@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/debugfs.h>
#include <linux/idr.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mfd/core.h>
#include <linux/pm_qos.h>
#include <linux/pm_runtime.h>
#include <linux/seq_file.h>
#include "intel-lpss.h"
#define LPSS_DEV_OFFSET 0x000
#define LPSS_DEV_SIZE 0x200
#define LPSS_PRIV_OFFSET 0x200
#define LPSS_PRIV_SIZE 0x100
#define LPSS_IDMA64_OFFSET 0x800
#define LPSS_IDMA64_SIZE 0x800
/* Offsets from lpss->priv */
#define LPSS_PRIV_RESETS 0x04
#define LPSS_PRIV_RESETS_FUNC BIT(2)
#define LPSS_PRIV_RESETS_IDMA 0x3
#define LPSS_PRIV_ACTIVELTR 0x10
#define LPSS_PRIV_IDLELTR 0x14
#define LPSS_PRIV_LTR_REQ BIT(15)
#define LPSS_PRIV_LTR_SCALE_MASK 0xc00
#define LPSS_PRIV_LTR_SCALE_1US 0x800
#define LPSS_PRIV_LTR_SCALE_32US 0xc00
#define LPSS_PRIV_LTR_VALUE_MASK 0x3ff
#define LPSS_PRIV_SSP_REG 0x20
#define LPSS_PRIV_SSP_REG_DIS_DMA_FIN BIT(0)
#define LPSS_PRIV_REMAP_ADDR_LO 0x40
#define LPSS_PRIV_REMAP_ADDR_HI 0x44
#define LPSS_PRIV_CAPS 0xfc
#define LPSS_PRIV_CAPS_NO_IDMA BIT(8)
#define LPSS_PRIV_CAPS_TYPE_SHIFT 4
#define LPSS_PRIV_CAPS_TYPE_MASK (0xf << LPSS_PRIV_CAPS_TYPE_SHIFT)
/* This matches the type field in CAPS register */
enum intel_lpss_dev_type {
LPSS_DEV_I2C = 0,
LPSS_DEV_UART,
LPSS_DEV_SPI,
};
struct intel_lpss {
const struct intel_lpss_platform_info *info;
enum intel_lpss_dev_type type;
struct clk *clk;
struct clk_lookup *clock;
const struct mfd_cell *cell;
struct device *dev;
void __iomem *priv;
int devid;
u32 caps;
u32 active_ltr;
u32 idle_ltr;
struct dentry *debugfs;
};
static const struct resource intel_lpss_dev_resources[] = {
DEFINE_RES_MEM_NAMED(LPSS_DEV_OFFSET, LPSS_DEV_SIZE, "lpss_dev"),
DEFINE_RES_MEM_NAMED(LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE, "lpss_priv"),
DEFINE_RES_IRQ(0),
};
static const struct resource intel_lpss_idma64_resources[] = {
DEFINE_RES_MEM(LPSS_IDMA64_OFFSET, LPSS_IDMA64_SIZE),
DEFINE_RES_IRQ(0),
};
#define LPSS_IDMA64_DRIVER_NAME "idma64"
/*
* Cells needs to be ordered so that the iDMA is created first. This is
* because we need to be sure the DMA is available when the host controller
* driver is probed.
*/
static const struct mfd_cell intel_lpss_idma64_cell = {
.name = LPSS_IDMA64_DRIVER_NAME,
.num_resources = ARRAY_SIZE(intel_lpss_idma64_resources),
.resources = intel_lpss_idma64_resources,
};
static const struct mfd_cell intel_lpss_i2c_cell = {
.name = "i2c_designware",
.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
.resources = intel_lpss_dev_resources,
};
static const struct mfd_cell intel_lpss_uart_cell = {
.name = "dw-apb-uart",
.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
.resources = intel_lpss_dev_resources,
};
static const struct mfd_cell intel_lpss_spi_cell = {
.name = "pxa2xx-spi",
.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
.resources = intel_lpss_dev_resources,
};
static DEFINE_IDA(intel_lpss_devid_ida);
static struct dentry *intel_lpss_debugfs;
static int intel_lpss_request_dma_module(const char *name)
{
static bool intel_lpss_dma_requested;
if (intel_lpss_dma_requested)
return 0;
intel_lpss_dma_requested = true;
return request_module("%s", name);
}
static void intel_lpss_cache_ltr(struct intel_lpss *lpss)
{
lpss->active_ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
lpss->idle_ltr = readl(lpss->priv + LPSS_PRIV_IDLELTR);
}
static int intel_lpss_debugfs_add(struct intel_lpss *lpss)
{
struct dentry *dir;
dir = debugfs_create_dir(dev_name(lpss->dev), intel_lpss_debugfs);
if (IS_ERR(dir))
return PTR_ERR(dir);
/* Cache the values into lpss structure */
intel_lpss_cache_ltr(lpss);
debugfs_create_x32("capabilities", S_IRUGO, dir, &lpss->caps);
debugfs_create_x32("active_ltr", S_IRUGO, dir, &lpss->active_ltr);
debugfs_create_x32("idle_ltr", S_IRUGO, dir, &lpss->idle_ltr);
lpss->debugfs = dir;
return 0;
}
static void intel_lpss_debugfs_remove(struct intel_lpss *lpss)
{
debugfs_remove_recursive(lpss->debugfs);
}
static void intel_lpss_ltr_set(struct device *dev, s32 val)
{
struct intel_lpss *lpss = dev_get_drvdata(dev);
u32 ltr;
/*
* Program latency tolerance (LTR) accordingly what has been asked
* by the PM QoS layer or disable it in case we were passed
* negative value or PM_QOS_LATENCY_ANY.
*/
ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
if (val == PM_QOS_LATENCY_ANY || val < 0) {
ltr &= ~LPSS_PRIV_LTR_REQ;
} else {
ltr |= LPSS_PRIV_LTR_REQ;
ltr &= ~LPSS_PRIV_LTR_SCALE_MASK;
ltr &= ~LPSS_PRIV_LTR_VALUE_MASK;
if (val > LPSS_PRIV_LTR_VALUE_MASK)
ltr |= LPSS_PRIV_LTR_SCALE_32US | val >> 5;
else
ltr |= LPSS_PRIV_LTR_SCALE_1US | val;
}
if (ltr == lpss->active_ltr)
return;
writel(ltr, lpss->priv + LPSS_PRIV_ACTIVELTR);
writel(ltr, lpss->priv + LPSS_PRIV_IDLELTR);
/* Cache the values into lpss structure */
intel_lpss_cache_ltr(lpss);
}
static void intel_lpss_ltr_expose(struct intel_lpss *lpss)
{
lpss->dev->power.set_latency_tolerance = intel_lpss_ltr_set;
dev_pm_qos_expose_latency_tolerance(lpss->dev);
}
static void intel_lpss_ltr_hide(struct intel_lpss *lpss)
{
dev_pm_qos_hide_latency_tolerance(lpss->dev);
lpss->dev->power.set_latency_tolerance = NULL;
}
static int intel_lpss_assign_devs(struct intel_lpss *lpss)
{
unsigned int type;
type = lpss->caps & LPSS_PRIV_CAPS_TYPE_MASK;
type >>= LPSS_PRIV_CAPS_TYPE_SHIFT;
switch (type) {
case LPSS_DEV_I2C:
lpss->cell = &intel_lpss_i2c_cell;
break;
case LPSS_DEV_UART:
lpss->cell = &intel_lpss_uart_cell;
break;
case LPSS_DEV_SPI:
lpss->cell = &intel_lpss_spi_cell;
break;
default:
return -ENODEV;
}
lpss->type = type;
return 0;
}
static bool intel_lpss_has_idma(const struct intel_lpss *lpss)
{
return (lpss->caps & LPSS_PRIV_CAPS_NO_IDMA) == 0;
}
static void intel_lpss_set_remap_addr(const struct intel_lpss *lpss)
{
resource_size_t addr = lpss->info->mem->start;
writel(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR_LO);
#if BITS_PER_LONG > 32
writel(addr >> 32, lpss->priv + LPSS_PRIV_REMAP_ADDR_HI);
#else
writel(0, lpss->priv + LPSS_PRIV_REMAP_ADDR_HI);
#endif
}
static void intel_lpss_deassert_reset(const struct intel_lpss *lpss)
{
u32 value = LPSS_PRIV_RESETS_FUNC | LPSS_PRIV_RESETS_IDMA;
/* Bring out the device from reset */
writel(value, lpss->priv + LPSS_PRIV_RESETS);
}
static void intel_lpss_init_dev(const struct intel_lpss *lpss)
{
u32 value = LPSS_PRIV_SSP_REG_DIS_DMA_FIN;
intel_lpss_deassert_reset(lpss);
if (!intel_lpss_has_idma(lpss))
return;
intel_lpss_set_remap_addr(lpss);
/* Make sure that SPI multiblock DMA transfers are re-enabled */
if (lpss->type == LPSS_DEV_SPI)
writel(value, lpss->priv + LPSS_PRIV_SSP_REG);
}
static void intel_lpss_unregister_clock_tree(struct clk *clk)
{
struct clk *parent;
while (clk) {
parent = clk_get_parent(clk);
clk_unregister(clk);
clk = parent;
}
}
static int intel_lpss_register_clock_divider(struct intel_lpss *lpss,
const char *devname,
struct clk **clk)
{
char name[32];
struct clk *tmp = *clk;
snprintf(name, sizeof(name), "%s-enable", devname);
tmp = clk_register_gate(NULL, name, __clk_get_name(tmp), 0,
lpss->priv, 0, 0, NULL);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
snprintf(name, sizeof(name), "%s-div", devname);
tmp = clk_register_fractional_divider(NULL, name, __clk_get_name(tmp),
0, lpss->priv, 1, 15, 16, 15, 0,
NULL);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
*clk = tmp;
snprintf(name, sizeof(name), "%s-update", devname);
tmp = clk_register_gate(NULL, name, __clk_get_name(tmp),
CLK_SET_RATE_PARENT, lpss->priv, 31, 0, NULL);
if (IS_ERR(tmp))
return PTR_ERR(tmp);
*clk = tmp;
return 0;
}
static int intel_lpss_register_clock(struct intel_lpss *lpss)
{
const struct mfd_cell *cell = lpss->cell;
struct clk *clk;
char devname[24];
int ret;
if (!lpss->info->clk_rate)
return 0;
/* Root clock */
clk = clk_register_fixed_rate(NULL, dev_name(lpss->dev), NULL,
CLK_IS_ROOT, lpss->info->clk_rate);
if (IS_ERR(clk))
return PTR_ERR(clk);
snprintf(devname, sizeof(devname), "%s.%d", cell->name, lpss->devid);
/*
* Support for clock divider only if it has some preset value.
* Otherwise we assume that the divider is not used.
*/
if (lpss->type != LPSS_DEV_I2C) {
ret = intel_lpss_register_clock_divider(lpss, devname, &clk);
if (ret)
goto err_clk_register;
}
ret = -ENOMEM;
/* Clock for the host controller */
lpss->clock = clkdev_create(clk, lpss->info->clk_con_id, "%s", devname);
if (!lpss->clock)
goto err_clk_register;
lpss->clk = clk;
return 0;
err_clk_register:
intel_lpss_unregister_clock_tree(clk);
return ret;
}
static void intel_lpss_unregister_clock(struct intel_lpss *lpss)
{
if (IS_ERR_OR_NULL(lpss->clk))
return;
clkdev_drop(lpss->clock);
intel_lpss_unregister_clock_tree(lpss->clk);
}
int intel_lpss_probe(struct device *dev,
const struct intel_lpss_platform_info *info)
{
struct intel_lpss *lpss;
int ret;
if (!info || !info->mem || info->irq <= 0)
return -EINVAL;
lpss = devm_kzalloc(dev, sizeof(*lpss), GFP_KERNEL);
if (!lpss)
return -ENOMEM;
lpss->priv = devm_ioremap(dev, info->mem->start + LPSS_PRIV_OFFSET,
LPSS_PRIV_SIZE);
if (!lpss->priv)
return -ENOMEM;
lpss->info = info;
lpss->dev = dev;
lpss->caps = readl(lpss->priv + LPSS_PRIV_CAPS);
dev_set_drvdata(dev, lpss);
ret = intel_lpss_assign_devs(lpss);
if (ret)
return ret;
intel_lpss_init_dev(lpss);
lpss->devid = ida_simple_get(&intel_lpss_devid_ida, 0, 0, GFP_KERNEL);
if (lpss->devid < 0)
return lpss->devid;
ret = intel_lpss_register_clock(lpss);
if (ret)
goto err_clk_register;
intel_lpss_ltr_expose(lpss);
ret = intel_lpss_debugfs_add(lpss);
if (ret)
dev_warn(dev, "Failed to create debugfs entries\n");
if (intel_lpss_has_idma(lpss)) {
/*
* Ensure the DMA driver is loaded before the host
* controller device appears, so that the host controller
* driver can request its DMA channels as early as
* possible.
*
* If the DMA module is not there that's OK as well.
*/
intel_lpss_request_dma_module(LPSS_IDMA64_DRIVER_NAME);
ret = mfd_add_devices(dev, lpss->devid, &intel_lpss_idma64_cell,
1, info->mem, info->irq, NULL);
if (ret)
dev_warn(dev, "Failed to add %s, fallback to PIO\n",
LPSS_IDMA64_DRIVER_NAME);
}
ret = mfd_add_devices(dev, lpss->devid, lpss->cell,
1, info->mem, info->irq, NULL);
if (ret)
goto err_remove_ltr;
return 0;
err_remove_ltr:
intel_lpss_debugfs_remove(lpss);
intel_lpss_ltr_hide(lpss);
err_clk_register:
ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
return ret;
}
EXPORT_SYMBOL_GPL(intel_lpss_probe);
void intel_lpss_remove(struct device *dev)
{
struct intel_lpss *lpss = dev_get_drvdata(dev);
mfd_remove_devices(dev);
intel_lpss_debugfs_remove(lpss);
intel_lpss_ltr_hide(lpss);
intel_lpss_unregister_clock(lpss);
ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
}
EXPORT_SYMBOL_GPL(intel_lpss_remove);
static int resume_lpss_device(struct device *dev, void *data)
{
pm_runtime_resume(dev);
return 0;
}
int intel_lpss_prepare(struct device *dev)
{
/*
* Resume both child devices before entering system sleep. This
* ensures that they are in proper state before they get suspended.
*/
device_for_each_child_reverse(dev, NULL, resume_lpss_device);
return 0;
}
EXPORT_SYMBOL_GPL(intel_lpss_prepare);
int intel_lpss_suspend(struct device *dev)
{
return 0;
}
EXPORT_SYMBOL_GPL(intel_lpss_suspend);
int intel_lpss_resume(struct device *dev)
{
struct intel_lpss *lpss = dev_get_drvdata(dev);
intel_lpss_init_dev(lpss);
return 0;
}
EXPORT_SYMBOL_GPL(intel_lpss_resume);
static int __init intel_lpss_init(void)
{
intel_lpss_debugfs = debugfs_create_dir("intel_lpss", NULL);
return 0;
}
module_init(intel_lpss_init);
static void __exit intel_lpss_exit(void)
{
debugfs_remove(intel_lpss_debugfs);
}
module_exit(intel_lpss_exit);
MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
MODULE_DESCRIPTION("Intel LPSS core driver");
MODULE_LICENSE("GPL v2");

62
drivers/mfd/intel-lpss.h Normal file
View File

@ -0,0 +1,62 @@
/*
* Intel LPSS core support.
*
* Copyright (C) 2015, Intel Corporation
*
* Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
* Mika Westerberg <mika.westerberg@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __MFD_INTEL_LPSS_H
#define __MFD_INTEL_LPSS_H
struct device;
struct resource;
struct intel_lpss_platform_info {
struct resource *mem;
int irq;
unsigned long clk_rate;
const char *clk_con_id;
};
int intel_lpss_probe(struct device *dev,
const struct intel_lpss_platform_info *info);
void intel_lpss_remove(struct device *dev);
#ifdef CONFIG_PM
int intel_lpss_prepare(struct device *dev);
int intel_lpss_suspend(struct device *dev);
int intel_lpss_resume(struct device *dev);
#ifdef CONFIG_PM_SLEEP
#define INTEL_LPSS_SLEEP_PM_OPS \
.prepare = intel_lpss_prepare, \
.suspend = intel_lpss_suspend, \
.resume = intel_lpss_resume, \
.freeze = intel_lpss_suspend, \
.thaw = intel_lpss_resume, \
.poweroff = intel_lpss_suspend, \
.restore = intel_lpss_resume,
#endif
#define INTEL_LPSS_RUNTIME_PM_OPS \
.runtime_suspend = intel_lpss_suspend, \
.runtime_resume = intel_lpss_resume,
#else /* !CONFIG_PM */
#define INTEL_LPSS_SLEEP_PM_OPS
#define INTEL_LPSS_RUNTIME_PM_OPS
#endif /* CONFIG_PM */
#define INTEL_LPSS_PM_OPS(name) \
const struct dev_pm_ops name = { \
INTEL_LPSS_SLEEP_PM_OPS \
INTEL_LPSS_RUNTIME_PM_OPS \
}
#endif /* __MFD_INTEL_LPSS_H */

View File

@ -302,7 +302,7 @@ void mfd_remove_devices(struct device *parent)
{
atomic_t *cnts = NULL;
device_for_each_child(parent, &cnts, mfd_remove_devices_fn);
device_for_each_child_reverse(parent, &cnts, mfd_remove_devices_fn);
kfree(cnts);
}
EXPORT_SYMBOL(mfd_remove_devices);

View File

@ -958,6 +958,8 @@ extern int __must_check device_add(struct device *dev);
extern void device_del(struct device *dev);
extern int device_for_each_child(struct device *dev, void *data,
int (*fn)(struct device *dev, void *data));
extern int device_for_each_child_reverse(struct device *dev, void *data,
int (*fn)(struct device *dev, void *data));
extern struct device *device_find_child(struct device *dev, void *data,
int (*match)(struct device *dev, void *data));
extern int device_rename(struct device *dev, const char *new_name);

View File

@ -63,6 +63,7 @@ extern void klist_iter_init(struct klist *k, struct klist_iter *i);
extern void klist_iter_init_node(struct klist *k, struct klist_iter *i,
struct klist_node *n);
extern void klist_iter_exit(struct klist_iter *i);
extern struct klist_node *klist_prev(struct klist_iter *i);
extern struct klist_node *klist_next(struct klist_iter *i);
#endif

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@ -161,6 +161,8 @@ void dev_pm_qos_hide_flags(struct device *dev);
int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set);
s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev);
int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val);
int dev_pm_qos_expose_latency_tolerance(struct device *dev);
void dev_pm_qos_hide_latency_tolerance(struct device *dev);
static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev)
{
@ -229,6 +231,9 @@ static inline s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
{ return PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; }
static inline int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
{ return 0; }
static inline int dev_pm_qos_expose_latency_tolerance(struct device *dev)
{ return 0; }
static inline void dev_pm_qos_hide_latency_tolerance(struct device *dev) {}
static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev) { return 0; }
static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return 0; }

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@ -323,6 +323,47 @@ static struct klist_node *to_klist_node(struct list_head *n)
return container_of(n, struct klist_node, n_node);
}
/**
* klist_prev - Ante up prev node in list.
* @i: Iterator structure.
*
* First grab list lock. Decrement the reference count of the previous
* node, if there was one. Grab the prev node, increment its reference
* count, drop the lock, and return that prev node.
*/
struct klist_node *klist_prev(struct klist_iter *i)
{
void (*put)(struct klist_node *) = i->i_klist->put;
struct klist_node *last = i->i_cur;
struct klist_node *prev;
spin_lock(&i->i_klist->k_lock);
if (last) {
prev = to_klist_node(last->n_node.prev);
if (!klist_dec_and_del(last))
put = NULL;
} else
prev = to_klist_node(i->i_klist->k_list.prev);
i->i_cur = NULL;
while (prev != to_klist_node(&i->i_klist->k_list)) {
if (likely(!knode_dead(prev))) {
kref_get(&prev->n_ref);
i->i_cur = prev;
break;
}
prev = to_klist_node(prev->n_node.prev);
}
spin_unlock(&i->i_klist->k_lock);
if (put && last)
put(last);
return i->i_cur;
}
EXPORT_SYMBOL_GPL(klist_prev);
/**
* klist_next - Ante up next node in list.
* @i: Iterator structure.