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linux-sg2042/drivers/sn/ioc4.c

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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2005 Silicon Graphics, Inc. All Rights Reserved.
*/
/* This file contains the master driver module for use by SGI IOC4 subdrivers.
*
* It allocates any resources shared between multiple subdevices, and
* provides accessor functions (where needed) and the like for those
* resources. It also provides a mechanism for the subdevice modules
* to support loading and unloading.
*
* Non-shared resources (e.g. external interrupt A_INT_OUT register page
* alias, serial port and UART registers) are handled by the subdevice
* modules themselves.
*
* This is all necessary because IOC4 is not implemented as a multi-function
* PCI device, but an amalgamation of disparate registers for several
* types of device (ATA, serial, external interrupts). The normal
* resource management in the kernel doesn't have quite the right interfaces
* to handle this situation (e.g. multiple modules can't claim the same
* PCI ID), thus this IOC4 master module.
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/ioc4.h>
#include <linux/mmtimer.h>
#include <linux/rtc.h>
#include <linux/rwsem.h>
#include <asm/sn/addrs.h>
#include <asm/sn/clksupport.h>
#include <asm/sn/shub_mmr.h>
/***************
* Definitions *
***************/
/* Tweakable values */
/* PCI bus speed detection/calibration */
#define IOC4_CALIBRATE_COUNT 63 /* Calibration cycle period */
#define IOC4_CALIBRATE_CYCLES 256 /* Average over this many cycles */
#define IOC4_CALIBRATE_DISCARD 2 /* Discard first few cycles */
#define IOC4_CALIBRATE_LOW_MHZ 25 /* Lower bound on bus speed sanity */
#define IOC4_CALIBRATE_HIGH_MHZ 75 /* Upper bound on bus speed sanity */
#define IOC4_CALIBRATE_DEFAULT_MHZ 66 /* Assumed if sanity check fails */
/************************
* Submodule management *
************************/
static LIST_HEAD(ioc4_devices);
static DECLARE_RWSEM(ioc4_devices_rwsem);
static LIST_HEAD(ioc4_submodules);
static DECLARE_RWSEM(ioc4_submodules_rwsem);
/* Register an IOC4 submodule */
int
ioc4_register_submodule(struct ioc4_submodule *is)
{
struct ioc4_driver_data *idd;
down_write(&ioc4_submodules_rwsem);
list_add(&is->is_list, &ioc4_submodules);
up_write(&ioc4_submodules_rwsem);
/* Initialize submodule for each IOC4 */
if (!is->is_probe)
return 0;
down_read(&ioc4_devices_rwsem);
list_for_each_entry(idd, &ioc4_devices, idd_list) {
if (is->is_probe(idd)) {
printk(KERN_WARNING
"%s: IOC4 submodule %s probe failed "
"for pci_dev %s",
__FUNCTION__, module_name(is->is_owner),
pci_name(idd->idd_pdev));
}
}
up_read(&ioc4_devices_rwsem);
return 0;
}
/* Unregister an IOC4 submodule */
void
ioc4_unregister_submodule(struct ioc4_submodule *is)
{
struct ioc4_driver_data *idd;
down_write(&ioc4_submodules_rwsem);
list_del(&is->is_list);
up_write(&ioc4_submodules_rwsem);
/* Remove submodule for each IOC4 */
if (!is->is_remove)
return;
down_read(&ioc4_devices_rwsem);
list_for_each_entry(idd, &ioc4_devices, idd_list) {
if (is->is_remove(idd)) {
printk(KERN_WARNING
"%s: IOC4 submodule %s remove failed "
"for pci_dev %s.\n",
__FUNCTION__, module_name(is->is_owner),
pci_name(idd->idd_pdev));
}
}
up_read(&ioc4_devices_rwsem);
}
/*********************
* Device management *
*********************/
#define IOC4_CALIBRATE_LOW_LIMIT \
(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
#define IOC4_CALIBRATE_HIGH_LIMIT \
(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
#define IOC4_CALIBRATE_DEFAULT \
(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)
#define IOC4_CALIBRATE_END \
(IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)
#define IOC4_INT_OUT_MODE_TOGGLE 0x7 /* Toggle INT_OUT every COUNT+1 ticks */
/* Determines external interrupt output clock period of the PCI bus an
* IOC4 is attached to. This value can be used to determine the PCI
* bus speed.
*
* IOC4 has a design feature that various internal timers are derived from
* the PCI bus clock. This causes IOC4 device drivers to need to take the
* bus speed into account when setting various register values (e.g. INT_OUT
* register COUNT field, UART divisors, etc). Since this information is
* needed by several subdrivers, it is determined by the main IOC4 driver,
* even though the following code utilizes external interrupt registers
* to perform the speed calculation.
*/
static void
ioc4_clock_calibrate(struct ioc4_driver_data *idd)
{
extern unsigned long sn_rtc_cycles_per_second;
union ioc4_int_out int_out;
union ioc4_gpcr gpcr;
unsigned int state, last_state = 1;
uint64_t start = 0, end, period;
unsigned int count = 0;
/* Enable output */
gpcr.raw = 0;
gpcr.fields.dir = IOC4_GPCR_DIR_0;
gpcr.fields.int_out_en = 1;
writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);
/* Reset to power-on state */
writel(0, &idd->idd_misc_regs->int_out.raw);
mmiowb();
printk(KERN_INFO
"%s: Calibrating PCI bus speed "
"for pci_dev %s ... ", __FUNCTION__, pci_name(idd->idd_pdev));
/* Set up square wave */
int_out.raw = 0;
int_out.fields.count = IOC4_CALIBRATE_COUNT;
int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
int_out.fields.diag = 0;
writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
mmiowb();
/* Check square wave period averaged over some number of cycles */
do {
int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
state = int_out.fields.int_out;
if (!last_state && state) {
count++;
if (count == IOC4_CALIBRATE_END) {
end = rtc_time();
break;
} else if (count == IOC4_CALIBRATE_DISCARD)
start = rtc_time();
}
last_state = state;
} while (1);
/* Calculation rearranged to preserve intermediate precision.
* Logically:
* 1. "end - start" gives us number of RTC cycles over all the
* square wave cycles measured.
* 2. Divide by number of square wave cycles to get number of
* RTC cycles per square wave cycle.
* 3. Divide by 2*(int_out.fields.count+1), which is the formula
* by which the IOC4 generates the square wave, to get the
* number of RTC cycles per IOC4 INT_OUT count.
* 4. Divide by sn_rtc_cycles_per_second to get seconds per
* count.
* 5. Multiply by 1E9 to get nanoseconds per count.
*/
period = ((end - start) * 1000000000) /
(IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1)
* sn_rtc_cycles_per_second);
/* Bounds check the result. */
if (period > IOC4_CALIBRATE_LOW_LIMIT ||
period < IOC4_CALIBRATE_HIGH_LIMIT) {
printk("failed. Assuming PCI clock ticks are %d ns.\n",
IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
period = IOC4_CALIBRATE_DEFAULT;
} else {
printk("succeeded. PCI clock ticks are %ld ns.\n",
period / IOC4_EXTINT_COUNT_DIVISOR);
}
/* Remember results. We store the extint clock period rather
* than the PCI clock period so that greater precision is
* retained. Divide by IOC4_EXTINT_COUNT_DIVISOR to get
* PCI clock period.
*/
idd->count_period = period;
}
/* Adds a new instance of an IOC4 card */
static int
ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
{
struct ioc4_driver_data *idd;
struct ioc4_submodule *is;
uint32_t pcmd;
int ret;
/* Enable IOC4 and take ownership of it */
if ((ret = pci_enable_device(pdev))) {
printk(KERN_WARNING
"%s: Failed to enable IOC4 device for pci_dev %s.\n",
__FUNCTION__, pci_name(pdev));
goto out;
}
pci_set_master(pdev);
/* Set up per-IOC4 data */
idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
if (!idd) {
printk(KERN_WARNING
"%s: Failed to allocate IOC4 data for pci_dev %s.\n",
__FUNCTION__, pci_name(pdev));
ret = -ENODEV;
goto out_idd;
}
idd->idd_pdev = pdev;
idd->idd_pci_id = pci_id;
/* Map IOC4 misc registers. These are shared between subdevices
* so the main IOC4 module manages them.
*/
idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
if (!idd->idd_bar0) {
printk(KERN_WARNING
"%s: Unable to find IOC4 misc resource "
"for pci_dev %s.\n",
__FUNCTION__, pci_name(idd->idd_pdev));
ret = -ENODEV;
goto out_pci;
}
if (!request_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
"ioc4_misc")) {
printk(KERN_WARNING
"%s: Unable to request IOC4 misc region "
"for pci_dev %s.\n",
__FUNCTION__, pci_name(idd->idd_pdev));
ret = -ENODEV;
goto out_pci;
}
idd->idd_misc_regs = ioremap(idd->idd_bar0,
sizeof(struct ioc4_misc_regs));
if (!idd->idd_misc_regs) {
printk(KERN_WARNING
"%s: Unable to remap IOC4 misc region "
"for pci_dev %s.\n",
__FUNCTION__, pci_name(idd->idd_pdev));
ret = -ENODEV;
goto out_misc_region;
}
/* Failsafe portion of per-IOC4 initialization */
/* Initialize IOC4 */
pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);
/* Determine PCI clock */
ioc4_clock_calibrate(idd);
/* Disable/clear all interrupts. Need to do this here lest
* one submodule request the shared IOC4 IRQ, but interrupt
* is generated by a different subdevice.
*/
/* Disable */
writel(~0, &idd->idd_misc_regs->other_iec.raw);
writel(~0, &idd->idd_misc_regs->sio_iec);
/* Clear (i.e. acknowledge) */
writel(~0, &idd->idd_misc_regs->other_ir.raw);
writel(~0, &idd->idd_misc_regs->sio_ir);
/* Track PCI-device specific data */
idd->idd_serial_data = NULL;
pci_set_drvdata(idd->idd_pdev, idd);
down_write(&ioc4_devices_rwsem);
list_add(&idd->idd_list, &ioc4_devices);
up_write(&ioc4_devices_rwsem);
/* Add this IOC4 to all submodules */
down_read(&ioc4_submodules_rwsem);
list_for_each_entry(is, &ioc4_submodules, is_list) {
if (is->is_probe && is->is_probe(idd)) {
printk(KERN_WARNING
"%s: IOC4 submodule 0x%s probe failed "
"for pci_dev %s.\n",
__FUNCTION__, module_name(is->is_owner),
pci_name(idd->idd_pdev));
}
}
up_read(&ioc4_submodules_rwsem);
return 0;
out_misc_region:
release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
out_pci:
kfree(idd);
out_idd:
pci_disable_device(pdev);
out:
return ret;
}
/* Removes a particular instance of an IOC4 card. */
static void
ioc4_remove(struct pci_dev *pdev)
{
struct ioc4_submodule *is;
struct ioc4_driver_data *idd;
idd = pci_get_drvdata(pdev);
/* Remove this IOC4 from all submodules */
down_read(&ioc4_submodules_rwsem);
list_for_each_entry(is, &ioc4_submodules, is_list) {
if (is->is_remove && is->is_remove(idd)) {
printk(KERN_WARNING
"%s: IOC4 submodule 0x%s remove failed "
"for pci_dev %s.\n",
__FUNCTION__, module_name(is->is_owner),
pci_name(idd->idd_pdev));
}
}
up_read(&ioc4_submodules_rwsem);
/* Release resources */
iounmap(idd->idd_misc_regs);
if (!idd->idd_bar0) {
printk(KERN_WARNING
"%s: Unable to get IOC4 misc mapping for pci_dev %s. "
"Device removal may be incomplete.\n",
__FUNCTION__, pci_name(idd->idd_pdev));
}
release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
/* Disable IOC4 and relinquish */
pci_disable_device(pdev);
/* Remove and free driver data */
down_write(&ioc4_devices_rwsem);
list_del(&idd->idd_list);
up_write(&ioc4_devices_rwsem);
kfree(idd);
}
static struct pci_device_id ioc4_id_table[] = {
{PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
{0}
};
static struct pci_driver __devinitdata ioc4_driver = {
.name = "IOC4",
.id_table = ioc4_id_table,
.probe = ioc4_probe,
.remove = ioc4_remove,
};
MODULE_DEVICE_TABLE(pci, ioc4_id_table);
/*********************
* Module management *
*********************/
/* Module load */
static int __devinit
ioc4_init(void)
{
return pci_register_driver(&ioc4_driver);
}
/* Module unload */
static void __devexit
ioc4_exit(void)
{
pci_unregister_driver(&ioc4_driver);
}
module_init(ioc4_init);
module_exit(ioc4_exit);
MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ioc4_register_submodule);
EXPORT_SYMBOL(ioc4_unregister_submodule);
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