// SPDX-License-Identifier: GPL-2.0
/*
* Support for Intel IXP4xx PCI host controller
*
* Copyright (C) 2017 Linus Walleij <[email protected]>
*
* Based on the IXP4xx arch/arm/mach-ixp4xx/common-pci.c driver
* Copyright (C) 2002 Intel Corporation
* Copyright (C) 2003 Greg Ungerer <[email protected]>
* Copyright (C) 2003-2004 MontaVista Software, Inc.
* Copyright (C) 2005 Deepak Saxena <[email protected]>
* Copyright (C) 2005 Alessandro Zummo <[email protected]>
*
* TODO:
* - Test IO-space access
* - DMA support
*/
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/bits.h>
#include "../pci.h"
/* Register offsets */
#define IXP4XX_PCI_NP_AD 0x00
#define IXP4XX_PCI_NP_CBE 0x04
#define IXP4XX_PCI_NP_WDATA 0x08
#define IXP4XX_PCI_NP_RDATA 0x0c
#define IXP4XX_PCI_CRP_AD_CBE 0x10
#define IXP4XX_PCI_CRP_WDATA 0x14
#define IXP4XX_PCI_CRP_RDATA 0x18
#define IXP4XX_PCI_CSR 0x1c
#define IXP4XX_PCI_ISR 0x20
#define IXP4XX_PCI_INTEN 0x24
#define IXP4XX_PCI_DMACTRL 0x28
#define IXP4XX_PCI_AHBMEMBASE 0x2c
#define IXP4XX_PCI_AHBIOBASE 0x30
#define IXP4XX_PCI_PCIMEMBASE 0x34
#define IXP4XX_PCI_AHBDOORBELL 0x38
#define IXP4XX_PCI_PCIDOORBELL 0x3c
#define IXP4XX_PCI_ATPDMA0_AHBADDR 0x40
#define IXP4XX_PCI_ATPDMA0_PCIADDR 0x44
#define IXP4XX_PCI_ATPDMA0_LENADDR 0x48
#define IXP4XX_PCI_ATPDMA1_AHBADDR 0x4c
#define IXP4XX_PCI_ATPDMA1_PCIADDR 0x50
#define IXP4XX_PCI_ATPDMA1_LENADDR 0x54
/* CSR bit definitions */
#define IXP4XX_PCI_CSR_HOST BIT(0)
#define IXP4XX_PCI_CSR_ARBEN BIT(1)
#define IXP4XX_PCI_CSR_ADS BIT(2)
#define IXP4XX_PCI_CSR_PDS BIT(3)
#define IXP4XX_PCI_CSR_ABE BIT(4)
#define IXP4XX_PCI_CSR_DBT BIT(5)
#define IXP4XX_PCI_CSR_ASE BIT(8)
#define IXP4XX_PCI_CSR_IC BIT(15)
#define IXP4XX_PCI_CSR_PRST BIT(16)
/* ISR (Interrupt status) Register bit definitions */
#define IXP4XX_PCI_ISR_PSE BIT(0)
#define IXP4XX_PCI_ISR_PFE BIT(1)
#define IXP4XX_PCI_ISR_PPE BIT(2)
#define IXP4XX_PCI_ISR_AHBE BIT(3)
#define IXP4XX_PCI_ISR_APDC BIT(4)
#define IXP4XX_PCI_ISR_PADC BIT(5)
#define IXP4XX_PCI_ISR_ADB BIT(6)
#define IXP4XX_PCI_ISR_PDB BIT(7)
/* INTEN (Interrupt Enable) Register bit definitions */
#define IXP4XX_PCI_INTEN_PSE BIT(0)
#define IXP4XX_PCI_INTEN_PFE BIT(1)
#define IXP4XX_PCI_INTEN_PPE BIT(2)
#define IXP4XX_PCI_INTEN_AHBE BIT(3)
#define IXP4XX_PCI_INTEN_APDC BIT(4)
#define IXP4XX_PCI_INTEN_PADC BIT(5)
#define IXP4XX_PCI_INTEN_ADB BIT(6)
#define IXP4XX_PCI_INTEN_PDB BIT(7)
/* Shift value for byte enable on NP cmd/byte enable register */
#define IXP4XX_PCI_NP_CBE_BESL 4
/* PCI commands supported by NP access unit */
#define NP_CMD_IOREAD 0x2
#define NP_CMD_IOWRITE 0x3
#define NP_CMD_CONFIGREAD 0xa
#define NP_CMD_CONFIGWRITE 0xb
#define NP_CMD_MEMREAD 0x6
#define NP_CMD_MEMWRITE 0x7
/* Constants for CRP access into local config space */
#define CRP_AD_CBE_BESL 20
#define CRP_AD_CBE_WRITE 0x00010000
/* Special PCI configuration space registers for this controller */
#define IXP4XX_PCI_RTOTTO 0x40
struct ixp4xx_pci {
struct device *dev;
void __iomem *base;
bool errata_hammer;
bool host_mode;
};
/*
* The IXP4xx has a peculiar address bus that will change the
* byte order on SoC peripherals depending on whether the device
* operates in big-endian or little-endian mode. That means that
* readl() and writel() that always use little-endian access
* will not work for SoC peripherals such as the PCI controller
* when used in big-endian mode. The accesses to the individual
* PCI devices on the other hand, are always little-endian and
* can use readl() and writel().
*
* For local AHB bus access we need to use __raw_[readl|writel]()
* to make sure that we access the SoC devices in the CPU native
* endianness.
*/
static inline u32 ixp4xx_readl(struct ixp4xx_pci *p, u32 reg)
{
return __raw_readl(p->base + reg);
}
static inline void ixp4xx_writel(struct ixp4xx_pci *p, u32 reg, u32 val)
{
__raw_writel(val, p->base + reg);
}
static int ixp4xx_pci_check_master_abort(struct ixp4xx_pci *p)
{
u32 isr = ixp4xx_readl(p, IXP4XX_PCI_ISR);
if (isr & IXP4XX_PCI_ISR_PFE) {
/* Make sure the master abort bit is reset */
ixp4xx_writel(p, IXP4XX_PCI_ISR, IXP4XX_PCI_ISR_PFE);
dev_dbg(p->dev, "master abort detected\n");
return -EINVAL;
}
return 0;
}
static int ixp4xx_pci_read_indirect(struct ixp4xx_pci *p, u32 addr, u32 cmd, u32 *data)
{
ixp4xx_writel(p, IXP4XX_PCI_NP_AD, addr);
if (p->errata_hammer) {
int i;
/*
* PCI workaround - only works if NP PCI space reads have
* no side effects. Hammer the register and read twice 8
* times. last one will be good.
*/
for (i = 0; i < 8; i++) {
ixp4xx_writel(p, IXP4XX_PCI_NP_CBE, cmd);
*data = ixp4xx_readl(p, IXP4XX_PCI_NP_RDATA);
*data = ixp4xx_readl(p, IXP4XX_PCI_NP_RDATA);
}
} else {
ixp4xx_writel(p, IXP4XX_PCI_NP_CBE, cmd);
*data = ixp4xx_readl(p, IXP4XX_PCI_NP_RDATA);
}
return ixp4xx_pci_check_master_abort(p);
}
static int ixp4xx_pci_write_indirect(struct ixp4xx_pci *p, u32 addr, u32 cmd, u32 data)
{
ixp4xx_writel(p, IXP4XX_PCI_NP_AD, addr);
/* Set up the write */
ixp4xx_writel(p, IXP4XX_PCI_NP_CBE, cmd);
/* Execute the write by writing to NP_WDATA */
ixp4xx_writel(p, IXP4XX_PCI_NP_WDATA, data);
return ixp4xx_pci_check_master_abort(p);
}
static u32 ixp4xx_config_addr(u8 bus_num, u16 devfn, int where)
{
/* Root bus is always 0 in this hardware */
if (bus_num == 0) {
/* type 0 */
return (PCI_CONF1_ADDRESS(0, 0, PCI_FUNC(devfn), where) &
~PCI_CONF1_ENABLE) | BIT(32-PCI_SLOT(devfn));
} else {
/* type 1 */
return (PCI_CONF1_ADDRESS(bus_num, PCI_SLOT(devfn),
PCI_FUNC(devfn), where) &
~PCI_CONF1_ENABLE) | 1;
}
}
/*
* CRP functions are "Controller Configuration Port" accesses
* initiated from within this driver itself to read/write PCI
* control information in the config space.
*/
static u32 ixp4xx_crp_byte_lane_enable_bits(u32 n, int size)
{
if (size == 1)
return (0xf & ~BIT(n)) << CRP_AD_CBE_BESL;
if (size == 2)
return (0xf & ~(BIT(n) | BIT(n+1))) << CRP_AD_CBE_BESL;
if (size == 4)
return 0;
return 0xffffffff;
}
static int ixp4xx_crp_read_config(struct ixp4xx_pci *p, int where, int size,
u32 *value)
{
u32 n, cmd, val;
n = where % 4;
cmd = where & ~3;
dev_dbg(p->dev, "%s from %d size %d cmd %08x\n",
__func__, where, size, cmd);
ixp4xx_writel(p, IXP4XX_PCI_CRP_AD_CBE, cmd);
val = ixp4xx_readl(p, IXP4XX_PCI_CRP_RDATA);
val >>= (8*n);
switch (size) {
case 1:
val &= U8_MAX;
dev_dbg(p->dev, "%s read byte %02x\n", __func__, val);
break;
case 2:
val &= U16_MAX;
dev_dbg(p->dev, "%s read word %04x\n", __func__, val);
break;
case 4:
val &= U32_MAX;
dev_dbg(p->dev, "%s read long %08x\n", __func__, val);
break;
default:
/* Should not happen */
dev_err(p->dev, "%s illegal size\n", __func__);
return PCIBIOS_DEVICE_NOT_FOUND;
}
*value = val;
return PCIBIOS_SUCCESSFUL;
}
static int ixp4xx_crp_write_config(struct ixp4xx_pci *p, int where, int size,
u32 value)
{
u32 n, cmd, val;
n = where % 4;
cmd = ixp4xx_crp_byte_lane_enable_bits(n, size);
if (cmd == 0xffffffff)
return PCIBIOS_BAD_REGISTER_NUMBER;
cmd |= where & ~3;
cmd |= CRP_AD_CBE_WRITE;
val = value << (8*n);
dev_dbg(p->dev, "%s to %d size %d cmd %08x val %08x\n",
__func__, where, size, cmd, val);
ixp4xx_writel(p, IXP4XX_PCI_CRP_AD_CBE, cmd);
ixp4xx_writel(p, IXP4XX_PCI_CRP_WDATA, val);
return PCIBIOS_SUCCESSFUL;
}
/*
* Then follows the functions that read and write from the common PCI
* configuration space.
*/
static u32 ixp4xx_byte_lane_enable_bits(u32 n, int size)
{
if (size == 1)
return (0xf & ~BIT(n)) << 4;
if (size == 2)
return (0xf & ~(BIT(n) | BIT(n+1))) << 4;
if (size == 4)
return 0;
return 0xffffffff;
}
static int ixp4xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *value)
{
struct ixp4xx_pci *p = bus->sysdata;
u32 n, addr, val, cmd;
u8 bus_num = bus->number;
int ret;
*value = 0xffffffff;
n = where % 4;
cmd = ixp4xx_byte_lane_enable_bits(n, size);
if (cmd == 0xffffffff)
return PCIBIOS_BAD_REGISTER_NUMBER;
addr = ixp4xx_config_addr(bus_num, devfn, where);
cmd |= NP_CMD_CONFIGREAD;
dev_dbg(p->dev, "read_config from %d size %d dev %d:%d:%d address: %08x cmd: %08x\n",
where, size, bus_num, PCI_SLOT(devfn), PCI_FUNC(devfn), addr, cmd);
ret = ixp4xx_pci_read_indirect(p, addr, cmd, &val);
if (ret)
return PCIBIOS_DEVICE_NOT_FOUND;
val >>= (8*n);
switch (size) {
case 1:
val &= U8_MAX;
dev_dbg(p->dev, "%s read byte %02x\n", __func__, val);
break;
case 2:
val &= U16_MAX;
dev_dbg(p->dev, "%s read word %04x\n", __func__, val);
break;
case 4:
val &= U32_MAX;
dev_dbg(p->dev, "%s read long %08x\n", __func__, val);
break;
default:
/* Should not happen */
dev_err(p->dev, "%s illegal size\n", __func__);
return PCIBIOS_DEVICE_NOT_FOUND;
}
*value = val;
return PCIBIOS_SUCCESSFUL;
}
static int ixp4xx_pci_write_config(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 value)
{
struct ixp4xx_pci *p = bus->sysdata;
u32 n, addr, val, cmd;
u8 bus_num = bus->number;
int ret;
n = where % 4;
cmd = ixp4xx_byte_lane_enable_bits(n, size);
if (cmd == 0xffffffff)
return PCIBIOS_BAD_REGISTER_NUMBER;
addr = ixp4xx_config_addr(bus_num, devfn, where);
cmd |= NP_CMD_CONFIGWRITE;
val = value << (8*n);
dev_dbg(p->dev, "write_config_byte %#x to %d size %d dev %d:%d:%d addr: %08x cmd %08x\n",
value, where, size, bus_num, PCI_SLOT(devfn), PCI_FUNC(devfn), addr, cmd);
ret = ixp4xx_pci_write_indirect(p, addr, cmd, val);
if (ret)
return PCIBIOS_DEVICE_NOT_FOUND;
return PCIBIOS_SUCCESSFUL;
}
static struct pci_ops ixp4xx_pci_ops = {
.read = ixp4xx_pci_read_config,
.write = ixp4xx_pci_write_config,
};
static u32 ixp4xx_pci_addr_to_64mconf(phys_addr_t addr)
{
u8 base;
base = ((addr & 0xff000000) >> 24);
return (base << 24) | ((base + 1) << 16)
| ((base + 2) << 8) | (base + 3);
}
static int ixp4xx_pci_parse_map_ranges(struct ixp4xx_pci *p)
{
struct device *dev = p->dev;
struct pci_host_bridge *bridge = pci_host_bridge_from_priv(p);
struct resource_entry *win;
struct resource *res;
phys_addr_t addr;
win = resource_list_first_type(&bridge->windows, IORESOURCE_MEM);
if (win) {
u32 pcimembase;
res = win->res;
addr = res->start - win->offset;
if (res->flags & IORESOURCE_PREFETCH)
res->name = "IXP4xx PCI PRE-MEM";
else
res->name = "IXP4xx PCI NON-PRE-MEM";
dev_dbg(dev, "%s window %pR, bus addr %pa\n",
res->name, res, &addr);
if (resource_size(res) != SZ_64M) {
dev_err(dev, "memory range is not 64MB\n");
return -EINVAL;
}
pcimembase = ixp4xx_pci_addr_to_64mconf(addr);
/* Commit configuration */
ixp4xx_writel(p, IXP4XX_PCI_PCIMEMBASE, pcimembase);
} else {
dev_err(dev, "no AHB memory mapping defined\n");
}
win = resource_list_first_type(&bridge->windows, IORESOURCE_IO);
if (win) {
res = win->res;
addr = pci_pio_to_address(res->start);
if (addr & 0xff) {
dev_err(dev, "IO mem at uneven address: %pa\n", &addr);
return -EINVAL;
}
res->name = "IXP4xx PCI IO MEM";
/*
* Setup I/O space location for PCI->AHB access, the
* upper 24 bits of the address goes into the lower
* 24 bits of this register.
*/
ixp4xx_writel(p, IXP4XX_PCI_AHBIOBASE, (addr >> 8));
} else {
dev_info(dev, "no IO space AHB memory mapping defined\n");
}
return 0;
}
static int ixp4xx_pci_parse_map_dma_ranges(struct ixp4xx_pci *p)
{
struct device *dev = p->dev;
struct pci_host_bridge *bridge = pci_host_bridge_from_priv(p);
struct resource_entry *win;
struct resource *res;
phys_addr_t addr;
u32 ahbmembase;
win = resource_list_first_type(&bridge->dma_ranges, IORESOURCE_MEM);
if (win) {
res = win->res;
addr = res->start - win->offset;
if (resource_size(res) != SZ_64M) {
dev_err(dev, "DMA memory range is not 64MB\n");
return -EINVAL;
}
dev_dbg(dev, "DMA MEM BASE: %pa\n", &addr);
/*
* 4 PCI-to-AHB windows of 16 MB each, write the 8 high bits
* into each byte of the PCI_AHBMEMBASE register.
*/
ahbmembase = ixp4xx_pci_addr_to_64mconf(addr);
/* Commit AHB membase */
ixp4xx_writel(p, IXP4XX_PCI_AHBMEMBASE, ahbmembase);
} else {
dev_err(dev, "no DMA memory range defined\n");
}
return 0;
}
/* Only used to get context for abort handling */
static struct ixp4xx_pci *ixp4xx_pci_abort_singleton;
static int ixp4xx_pci_abort_handler(unsigned long addr, unsigned int fsr,
struct pt_regs *regs)
{
struct ixp4xx_pci *p = ixp4xx_pci_abort_singleton;
u32 isr, status;
int ret;
isr = ixp4xx_readl(p, IXP4XX_PCI_ISR);
ret = ixp4xx_crp_read_config(p, PCI_STATUS, 2, &status);
if (ret) {
dev_err(p->dev, "unable to read abort status\n");
return -EINVAL;
}
dev_err(p->dev,
"PCI: abort_handler addr = %#lx, isr = %#x, status = %#x\n",
addr, isr, status);
/* Make sure the Master Abort bit is reset */
ixp4xx_writel(p, IXP4XX_PCI_ISR, IXP4XX_PCI_ISR_PFE);
status |= PCI_STATUS_REC_MASTER_ABORT;
ret = ixp4xx_crp_write_config(p, PCI_STATUS, 2, status);
if (ret)
dev_err(p->dev, "unable to clear abort status bit\n");
/*
* If it was an imprecise abort, then we need to correct the
* return address to be _after_ the instruction.
*/
if (fsr & (1 << 10)) {
dev_err(p->dev, "imprecise abort\n");
regs->ARM_pc += 4;
}
return 0;
}
static int __init ixp4xx_pci_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct ixp4xx_pci *p;
struct pci_host_bridge *host;
int ret;
u32 val;
phys_addr_t addr;
u32 basereg[4] = {
PCI_BASE_ADDRESS_0,
PCI_BASE_ADDRESS_1,
PCI_BASE_ADDRESS_2,
PCI_BASE_ADDRESS_3,
};
int i;
host = devm_pci_alloc_host_bridge(dev, sizeof(*p));
if (!host)
return -ENOMEM;
host->ops = &ixp4xx_pci_ops;
p = pci_host_bridge_priv(host);
host->sysdata = p;
p->dev = dev;
dev_set_drvdata(dev, p);
/*
* Set up quirk for erratic behaviour in the 42x variant
* when accessing config space.
*/
if (of_device_is_compatible(np, "intel,ixp42x-pci")) {
p->errata_hammer = true;
dev_info(dev, "activate hammering errata\n");
}
p->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(p->base))
return PTR_ERR(p->base);
val = ixp4xx_readl(p, IXP4XX_PCI_CSR);
p->host_mode = !!(val & IXP4XX_PCI_CSR_HOST);
dev_info(dev, "controller is in %s mode\n",
p->host_mode ? "host" : "option");
/* Hook in our fault handler for PCI errors */
ixp4xx_pci_abort_singleton = p;
hook_fault_code(16+6, ixp4xx_pci_abort_handler, SIGBUS, 0,
"imprecise external abort");
ret = ixp4xx_pci_parse_map_ranges(p);
if (ret)
return ret;
ret = ixp4xx_pci_parse_map_dma_ranges(p);
if (ret)
return ret;
/* This is only configured in host mode */
if (p->host_mode) {
addr = __pa(PAGE_OFFSET);
/* This is a noop (0x00) but explains what is going on */
addr |= PCI_BASE_ADDRESS_SPACE_MEMORY;
for (i = 0; i < 4; i++) {
/* Write this directly into the config space */
ret = ixp4xx_crp_write_config(p, basereg[i], 4, addr);
if (ret)
dev_err(dev, "failed to set up PCI_BASE_ADDRESS_%d\n", i);
else
dev_info(dev, "set PCI_BASE_ADDR_%d to %pa\n", i, &addr);
addr += SZ_16M;
}
/*
* Enable CSR window at 64 MiB to allow PCI masters to continue
* prefetching past the 64 MiB boundary, if all AHB to PCI
* windows are consecutive.
*/
ret = ixp4xx_crp_write_config(p, PCI_BASE_ADDRESS_4, 4, addr);
if (ret)
dev_err(dev, "failed to set up PCI_BASE_ADDRESS_4\n");
else
dev_info(dev, "set PCI_BASE_ADDR_4 to %pa\n", &addr);
/*
* Put the IO memory window at the very end of physical memory
* at 0xfffffc00. This is when the system is trying to access IO
* memory over AHB.
*/
addr = 0xfffffc00;
addr |= PCI_BASE_ADDRESS_SPACE_IO;
ret = ixp4xx_crp_write_config(p, PCI_BASE_ADDRESS_5, 4, addr);
if (ret)
dev_err(dev, "failed to set up PCI_BASE_ADDRESS_5\n");
else
dev_info(dev, "set PCI_BASE_ADDR_5 to %pa\n", &addr);
/*
* Retry timeout to 0x80
* Transfer ready timeout to 0xff
*/
ret = ixp4xx_crp_write_config(p, IXP4XX_PCI_RTOTTO, 4,
0x000080ff);
if (ret)
dev_err(dev, "failed to set up TRDY limit\n");
else
dev_info(dev, "set TRDY limit to 0x80ff\n");
}
/* Clear interrupts */
val = IXP4XX_PCI_ISR_PSE | IXP4XX_PCI_ISR_PFE | IXP4XX_PCI_ISR_PPE | IXP4XX_PCI_ISR_AHBE;
ixp4xx_writel(p, IXP4XX_PCI_ISR, val);
/*
* Set Initialize Complete in PCI Control Register: allow IXP4XX to
* generate PCI configuration cycles. Specify that the AHB bus is
* operating in big-endian mode. Set up byte lane swapping between
* little-endian PCI and the big-endian AHB bus.
*/
val = IXP4XX_PCI_CSR_IC | IXP4XX_PCI_CSR_ABE;
if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
val |= (IXP4XX_PCI_CSR_PDS | IXP4XX_PCI_CSR_ADS);
ixp4xx_writel(p, IXP4XX_PCI_CSR, val);
ret = ixp4xx_crp_write_config(p, PCI_COMMAND, 2, PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
if (ret)
dev_err(dev, "unable to initialize master and command memory\n");
else
dev_info(dev, "initialized as master\n");
pci_host_probe(host);
return 0;
}
static const struct of_device_id ixp4xx_pci_of_match[] = {
{
.compatible = "intel,ixp42x-pci",
},
{
.compatible = "intel,ixp43x-pci",
},
{},
};
/*
* This driver needs to be a builtin module with suppressed bind
* attributes since the probe() is initializing a hard exception
* handler and this can only be done from __init-tagged code
* sections. This module cannot be removed and inserted at all.
*/
static struct platform_driver ixp4xx_pci_driver = {
.driver = {
.name = "ixp4xx-pci",
.suppress_bind_attrs = true,
.of_match_table = ixp4xx_pci_of_match,
},
};
builtin_platform_driver_probe(ixp4xx_pci_driver, ixp4xx_pci_probe);
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