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PCI: thunder: Add PCIe host driver for ThunderX processors 

The root complexes used to access off-chip PCIe devices (called PEM units
in the hardware manuals) on some Cavium ThunderX processors require quirky
access methods for the config space of the PCIe bridge.

Add a driver to provide these config space accessor functions.  Use the
pci-host-common code to configure the PCI machinery.

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
David Daney 2016-03-04 14:31:47 -08:00 committed by Bjorn Helgaas
parent 4e64dbe226
commit f12b76e56a
5 changed files with 405 additions and 0 deletions
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43
Documentation/devicetree/bindings/pci/pci-thunder-pem.txt Normal file
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@ -0,0 +1,43 @@
* ThunderX PEM PCIe host controller
Firmware-initialized PCI host controller found on some Cavium
ThunderX processors.
The properties and their meanings are identical to those described in
host-generic-pci.txt except as listed below.
Properties of the host controller node that differ from
host-generic-pci.txt:
- compatible : Must be "cavium,pci-host-thunder-pem"
- reg : Two entries: First the configuration space for down
stream devices base address and size, as accessed
from the parent bus. Second, the register bank of
the PEM device PCIe bridge.
Example:
pci@87e0,c2000000 {
compatible = "cavium,pci-host-thunder-pem";
device_type = "pci";
msi-parent = <&its>;
msi-map = <0 &its 0x10000 0x10000>;
bus-range = <0x8f 0xc7>;
#size-cells = <2>;
#address-cells = <3>;
reg = <0x8880 0x8f000000 0x0 0x39000000>, /* Configuration space */
<0x87e0 0xc2000000 0x0 0x00010000>; /* PEM space */
ranges = <0x01000000 0x00 0x00020000 0x88b0 0x00020000 0x00 0x00010000>, /* I/O */
<0x03000000 0x00 0x10000000 0x8890 0x10000000 0x0f 0xf0000000>, /* mem64 */
<0x43000000 0x10 0x00000000 0x88a0 0x00000000 0x10 0x00000000>, /* mem64-pref */
<0x03000000 0x87e0 0xc2f00000 0x87e0 0xc2000000 0x00 0x00100000>; /* mem64 PEM BAR4 */
#interrupt-cells = <1>;
interrupt-map-mask = <0 0 0 7>;
interrupt-map = <0 0 0 1 &gic0 0 0 0 24 4>, /* INTA */
<0 0 0 2 &gic0 0 0 0 25 4>, /* INTB */
<0 0 0 3 &gic0 0 0 0 26 4>, /* INTC */
<0 0 0 4 &gic0 0 0 0 27 4>; /* INTD */
};

8
MAINTAINERS
View File

@ -8419,6 +8419,14 @@ L: linux-arm-msm@vger.kernel.org
S: Maintained
F: drivers/pci/host/*qcom*
PCIE DRIVER FOR CAVIUM THUNDERX
M: David Daney <david.daney@cavium.com>
L: linux-pci@vger.kernel.org
L: linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
S: Supported
F: Documentation/devicetree/bindings/pci/pci-thunder-*
F: drivers/pci/host/pci-thunder-*
PCMCIA SUBSYSTEM
P: Linux PCMCIA Team
L: linux-pcmcia@lists.infradead.org

7
drivers/pci/host/Kconfig
View File

@ -195,4 +195,11 @@ config PCIE_QCOM
PCIe controller uses the Designware core plus Qualcomm-specific
hardware wrappers.
config PCI_HOST_THUNDER_PEM
bool "Cavium Thunder PCIe controller to off-chip devices"
depends on OF && ARM64
select PCI_HOST_COMMON
help
Say Y here if you want PCIe support for CN88XX Cavium Thunder SoCs.
endmenu

1
drivers/pci/host/Makefile
View File

@ -23,3 +23,4 @@ obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
obj-$(CONFIG_PCI_HISI) += pcie-hisi.o
obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.o

346
drivers/pci/host/pci-thunder-pem.c Normal file
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@ -0,0 +1,346 @@
/*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright (C) 2015 - 2016 Cavium, Inc.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include <linux/platform_device.h>
#include "pci-host-common.h"
#define PEM_CFG_WR 0x28
#define PEM_CFG_RD 0x30
struct thunder_pem_pci {
struct gen_pci gen_pci;
u32 ea_entry[3];
void __iomem *pem_reg_base;
};
static void __iomem *thunder_pem_map_bus(struct pci_bus *bus,
unsigned int devfn, int where)
{
struct gen_pci *pci = bus->sysdata;
resource_size_t idx = bus->number - pci->cfg.bus_range->start;
return pci->cfg.win[idx] + ((devfn << 16) | where);
}
static int thunder_pem_bridge_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
u64 read_val;
struct thunder_pem_pci *pem_pci;
struct gen_pci *pci = bus->sysdata;
pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci);
if (devfn != 0 || where >= 2048) {
*val = ~0;
return PCIBIOS_DEVICE_NOT_FOUND;
}
/*
* 32-bit accesses only. Write the address to the low order
* bits of PEM_CFG_RD, then trigger the read by reading back.
* The config data lands in the upper 32-bits of PEM_CFG_RD.
*/
read_val = where & ~3ull;
writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
read_val >>= 32;
/*
* The config space contains some garbage, fix it up. Also
* synthesize an EA capability for the BAR used by MSI-X.
*/
switch (where & ~3) {
case 0x40:
read_val &= 0xffff00ff;
read_val |= 0x00007000; /* Skip MSI CAP */
break;
case 0x70: /* Express Cap */
/* PME interrupt on vector 2*/
read_val |= (2u << 25);
break;
case 0xb0: /* MSI-X Cap */
/* TableSize=4, Next Cap is EA */
read_val &= 0xc00000ff;
read_val |= 0x0003bc00;
break;
case 0xb4:
/* Table offset=0, BIR=0 */
read_val = 0x00000000;
break;
case 0xb8:
/* BPA offset=0xf0000, BIR=0 */
read_val = 0x000f0000;
break;
case 0xbc:
/* EA, 1 entry, no next Cap */
read_val = 0x00010014;
break;
case 0xc0:
/* DW2 for type-1 */
read_val = 0x00000000;
break;
case 0xc4:
/* Entry BEI=0, PP=0x00, SP=0xff, ES=3 */
read_val = 0x80ff0003;
break;
case 0xc8:
read_val = pem_pci->ea_entry[0];
break;
case 0xcc:
read_val = pem_pci->ea_entry[1];
break;
case 0xd0:
read_val = pem_pci->ea_entry[2];
break;
default:
break;
}
read_val >>= (8 * (where & 3));
switch (size) {
case 1:
read_val &= 0xff;
break;
case 2:
read_val &= 0xffff;
break;
default:
break;
}
*val = read_val;
return PCIBIOS_SUCCESSFUL;
}
static int thunder_pem_config_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
struct gen_pci *pci = bus->sysdata;
if (bus->number < pci->cfg.bus_range->start ||
bus->number > pci->cfg.bus_range->end)
return PCIBIOS_DEVICE_NOT_FOUND;
/*
* The first device on the bus is the PEM PCIe bridge.
* Special case its config access.
*/
if (bus->number == pci->cfg.bus_range->start)
return thunder_pem_bridge_read(bus, devfn, where, size, val);
return pci_generic_config_read(bus, devfn, where, size, val);
}
/*
* Some of the w1c_bits below also include read-only or non-writable
* reserved bits, this makes the code simpler and is OK as the bits
* are not affected by writing zeros to them.
*/
static u32 thunder_pem_bridge_w1c_bits(int where)
{
u32 w1c_bits = 0;
switch (where & ~3) {
case 0x04: /* Command/Status */
case 0x1c: /* Base and I/O Limit/Secondary Status */
w1c_bits = 0xff000000;
break;
case 0x44: /* Power Management Control and Status */
w1c_bits = 0xfffffe00;
break;
case 0x78: /* Device Control/Device Status */
case 0x80: /* Link Control/Link Status */
case 0x88: /* Slot Control/Slot Status */
case 0x90: /* Root Status */
case 0xa0: /* Link Control 2 Registers/Link Status 2 */
w1c_bits = 0xffff0000;
break;
case 0x104: /* Uncorrectable Error Status */
case 0x110: /* Correctable Error Status */
case 0x130: /* Error Status */
case 0x160: /* Link Control 4 */
w1c_bits = 0xffffffff;
break;
default:
break;
}
return w1c_bits;
}
static int thunder_pem_bridge_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
struct gen_pci *pci = bus->sysdata;
struct thunder_pem_pci *pem_pci;
u64 write_val, read_val;
u32 mask = 0;
pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci);
if (devfn != 0 || where >= 2048)
return PCIBIOS_DEVICE_NOT_FOUND;
/*
* 32-bit accesses only. If the write is for a size smaller
* than 32-bits, we must first read the 32-bit value and merge
* in the desired bits and then write the whole 32-bits back
* out.
*/
switch (size) {
case 1:
read_val = where & ~3ull;
writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
read_val >>= 32;
mask = ~(0xff << (8 * (where & 3)));
read_val &= mask;
val = (val & 0xff) << (8 * (where & 3));
val |= (u32)read_val;
break;
case 2:
read_val = where & ~3ull;
writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
read_val >>= 32;
mask = ~(0xffff << (8 * (where & 3)));
read_val &= mask;
val = (val & 0xffff) << (8 * (where & 3));
val |= (u32)read_val;
break;
default:
break;
}
/*
* By expanding the write width to 32 bits, we may
* inadvertently hit some W1C bits that were not intended to
* be written. Calculate the mask that must be applied to the
* data to be written to avoid these cases.
*/
if (mask) {
u32 w1c_bits = thunder_pem_bridge_w1c_bits(where);
if (w1c_bits) {
mask &= w1c_bits;
val &= ~mask;
}
}
/*
* Low order bits are the config address, the high order 32
* bits are the data to be written.
*/
write_val = where & ~3ull;
write_val |= (((u64)val) << 32);
writeq(write_val, pem_pci->pem_reg_base + PEM_CFG_WR);
return PCIBIOS_SUCCESSFUL;
}
static int thunder_pem_config_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
struct gen_pci *pci = bus->sysdata;
if (bus->number < pci->cfg.bus_range->start ||
bus->number > pci->cfg.bus_range->end)
return PCIBIOS_DEVICE_NOT_FOUND;
/*
* The first device on the bus is the PEM PCIe bridge.
* Special case its config access.
*/
if (bus->number == pci->cfg.bus_range->start)
return thunder_pem_bridge_write(bus, devfn, where, size, val);
return pci_generic_config_write(bus, devfn, where, size, val);
}
static struct gen_pci_cfg_bus_ops thunder_pem_bus_ops = {
.bus_shift = 24,
.ops = {
.map_bus = thunder_pem_map_bus,
.read = thunder_pem_config_read,
.write = thunder_pem_config_write,
}
};
static const struct of_device_id thunder_pem_of_match[] = {
{ .compatible = "cavium,pci-host-thunder-pem",
.data = &thunder_pem_bus_ops },
{ },
};
MODULE_DEVICE_TABLE(of, thunder_pem_of_match);
static int thunder_pem_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct of_device_id *of_id;
resource_size_t bar4_start;
struct resource *res_pem;
struct thunder_pem_pci *pem_pci;
pem_pci = devm_kzalloc(dev, sizeof(*pem_pci), GFP_KERNEL);
if (!pem_pci)
return -ENOMEM;
of_id = of_match_node(thunder_pem_of_match, dev->of_node);
pem_pci->gen_pci.cfg.ops = (struct gen_pci_cfg_bus_ops *)of_id->data;
/*
* The second register range is the PEM bridge to the PCIe
* bus. It has a different config access method than those
* devices behind the bridge.
*/
res_pem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
if (!res_pem) {
dev_err(dev, "missing \"reg[1]\"property\n");
return -EINVAL;
}
pem_pci->pem_reg_base = devm_ioremap(dev, res_pem->start, 0x10000);
if (!pem_pci->pem_reg_base)
return -ENOMEM;
/*
* The MSI-X BAR for the PEM and AER interrupts is located at
* a fixed offset from the PEM register base. Generate a
* fragment of the synthesized Enhanced Allocation capability
* structure here for the BAR.
*/
bar4_start = res_pem->start + 0xf00000;
pem_pci->ea_entry[0] = (u32)bar4_start | 2;
pem_pci->ea_entry[1] = (u32)(res_pem->end - bar4_start) & ~3u;
pem_pci->ea_entry[2] = (u32)(bar4_start >> 32);
return pci_host_common_probe(pdev, &pem_pci->gen_pci);
}
static struct platform_driver thunder_pem_driver = {
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = thunder_pem_of_match,
},
.probe = thunder_pem_probe,
};
module_platform_driver(thunder_pem_driver);
MODULE_DESCRIPTION("Thunder PEM PCIe host driver");
MODULE_LICENSE("GPL v2");