linux/arch/mips/pci/ops-au1000.c
Alexander Bigga 32136568a9 [MIPS] Fix for pci config_access on alchemy au1x000
I've encountered a serious problem with PCI config space access on Au1x000
platforms with recent 2.6.x-kernel. With 2.4.31 the same hardware works fine.
So I was looking for the differences:

Symptoms:
- no PCI-device is seen on bootup though two or three cards are present
- lspci output is empty
- OR: lspci shows 20 times the same device
(- OR: in some slot-configurations it worked anyhow)

System(s):
1. platform with Au1500 and three PCI-devices (actually a mycable XXS1500
    with backplane for three PCI-devices)
2. platform with Au1550 and two PCI-devices (custom board)

Debugging:
I digged down to the config_access() of the au1xxx-processors in
arch/mips/pci/ops-au1000.c and switched on DEBUG.

The code of config_access() seems to be almost the same as of the
2.4.x-kernel. But the "pci_cfg_vm->addr" returned by get_vm_area(0x2000, 0)
once on booting is different. That's of course not forbidden. But the
alignment seems to be wrong. In my case, I received:

2.4.31: pci_cfg_vm->addr = c0000000
2.6.18-rc5: pci_cfg_vm->addr = c0101000

To make it short: With 2.6.x it fails on the first config-access with:
"PCI ERR detected: status 83a00356".

Fixup:
My fix is now, to use the VM_IOREMAP-flag in the get_vm_area call. This flag
seems to be introduced in mm/vmalloc.c a long time ago (in 2.6.7-bk13, I
found in gitweb).
Now, the returned address is pci_cfg_vm->addr = c0104000 and everything works
fine.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2006-09-27 13:37:38 +01:00

314 lines
8.2 KiB
C

/*
* BRIEF MODULE DESCRIPTION
* Alchemy/AMD Au1x00 pci support.
*
* Copyright 2001,2002,2003 MontaVista Software Inc.
* Author: MontaVista Software, Inc.
* ppopov@mvista.com or source@mvista.com
*
* Support for all devices (greater than 16) added by David Gathright.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <asm/mach-au1x00/au1000.h>
#undef DEBUG
#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif
#define PCI_ACCESS_READ 0
#define PCI_ACCESS_WRITE 1
int (*board_pci_idsel)(unsigned int devsel, int assert);
void mod_wired_entry(int entry, unsigned long entrylo0,
unsigned long entrylo1, unsigned long entryhi,
unsigned long pagemask)
{
unsigned long old_pagemask;
unsigned long old_ctx;
/* Save old context and create impossible VPN2 value */
old_ctx = read_c0_entryhi() & 0xff;
old_pagemask = read_c0_pagemask();
write_c0_index(entry);
write_c0_pagemask(pagemask);
write_c0_entryhi(entryhi);
write_c0_entrylo0(entrylo0);
write_c0_entrylo1(entrylo1);
tlb_write_indexed();
write_c0_entryhi(old_ctx);
write_c0_pagemask(old_pagemask);
}
struct vm_struct *pci_cfg_vm;
static int pci_cfg_wired_entry;
static int first_cfg = 1;
unsigned long last_entryLo0, last_entryLo1;
static int config_access(unsigned char access_type, struct pci_bus *bus,
unsigned int dev_fn, unsigned char where,
u32 * data)
{
#if defined( CONFIG_SOC_AU1500 ) || defined( CONFIG_SOC_AU1550 )
unsigned int device = PCI_SLOT(dev_fn);
unsigned int function = PCI_FUNC(dev_fn);
unsigned long offset, status;
unsigned long cfg_base;
unsigned long flags;
int error = PCIBIOS_SUCCESSFUL;
unsigned long entryLo0, entryLo1;
if (device > 19) {
*data = 0xffffffff;
return -1;
}
local_irq_save(flags);
au_writel(((0x2000 << 16) | (au_readl(Au1500_PCI_STATCMD) & 0xffff)),
Au1500_PCI_STATCMD);
au_sync_udelay(1);
/*
* We can't ioremap the entire pci config space because it's
* too large. Nor can we call ioremap dynamically because some
* device drivers use the pci config routines from within
* interrupt handlers and that becomes a problem in get_vm_area().
* We use one wired tlb to handle all config accesses for all
* busses. To improve performance, if the current device
* is the same as the last device accessed, we don't touch the
* tlb.
*/
if (first_cfg) {
/* reserve a wired entry for pci config accesses */
first_cfg = 0;
pci_cfg_vm = get_vm_area(0x2000, VM_IOREMAP);
if (!pci_cfg_vm)
panic (KERN_ERR "PCI unable to get vm area\n");
pci_cfg_wired_entry = read_c0_wired();
add_wired_entry(0, 0, (unsigned long)pci_cfg_vm->addr, PM_4K);
last_entryLo0 = last_entryLo1 = 0xffffffff;
}
/* Allow board vendors to implement their own off-chip idsel.
* If it doesn't succeed, may as well bail out at this point.
*/
if (board_pci_idsel) {
if (board_pci_idsel(device, 1) == 0) {
*data = 0xffffffff;
local_irq_restore(flags);
return -1;
}
}
/* setup the config window */
if (bus->number == 0) {
cfg_base = ((1<<device)<<11);
} else {
cfg_base = 0x80000000 | (bus->number<<16) | (device<<11);
}
/* setup the lower bits of the 36 bit address */
offset = (function << 8) | (where & ~0x3);
/* pick up any address that falls below the page mask */
offset |= cfg_base & ~PAGE_MASK;
/* page boundary */
cfg_base = cfg_base & PAGE_MASK;
entryLo0 = (6 << 26) | (cfg_base >> 6) | (2 << 3) | 7;
entryLo1 = (6 << 26) | (cfg_base >> 6) | (0x1000 >> 6) | (2 << 3) | 7;
if ((entryLo0 != last_entryLo0) || (entryLo1 != last_entryLo1)) {
mod_wired_entry(pci_cfg_wired_entry, entryLo0, entryLo1,
(unsigned long)pci_cfg_vm->addr, PM_4K);
last_entryLo0 = entryLo0;
last_entryLo1 = entryLo1;
}
if (access_type == PCI_ACCESS_WRITE) {
au_writel(*data, (int)(pci_cfg_vm->addr + offset));
} else {
*data = au_readl((int)(pci_cfg_vm->addr + offset));
}
au_sync_udelay(2);
DBG("cfg_access %d bus->number %d dev %d at %x *data %x conf %x\n",
access_type, bus->number, device, where, *data, offset);
/* check master abort */
status = au_readl(Au1500_PCI_STATCMD);
if (status & (1<<29)) {
*data = 0xffffffff;
error = -1;
DBG("Au1x Master Abort\n");
} else if ((status >> 28) & 0xf) {
DBG("PCI ERR detected: status %x\n", status);
*data = 0xffffffff;
error = -1;
}
/* Take away the idsel.
*/
if (board_pci_idsel) {
(void)board_pci_idsel(device, 0);
}
local_irq_restore(flags);
return error;
#endif
}
static int read_config_byte(struct pci_bus *bus, unsigned int devfn,
int where, u8 * val)
{
u32 data;
int ret;
ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);
if (where & 1)
data >>= 8;
if (where & 2)
data >>= 16;
*val = data & 0xff;
return ret;
}
static int read_config_word(struct pci_bus *bus, unsigned int devfn,
int where, u16 * val)
{
u32 data;
int ret;
ret = config_access(PCI_ACCESS_READ, bus, devfn, where, &data);
if (where & 2)
data >>= 16;
*val = data & 0xffff;
return ret;
}
static int read_config_dword(struct pci_bus *bus, unsigned int devfn,
int where, u32 * val)
{
int ret;
ret = config_access(PCI_ACCESS_READ, bus, devfn, where, val);
return ret;
}
static int
write_config_byte(struct pci_bus *bus, unsigned int devfn, int where,
u8 val)
{
u32 data = 0;
if (config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
return -1;
data = (data & ~(0xff << ((where & 3) << 3))) |
(val << ((where & 3) << 3));
if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
return -1;
return PCIBIOS_SUCCESSFUL;
}
static int
write_config_word(struct pci_bus *bus, unsigned int devfn, int where,
u16 val)
{
u32 data = 0;
if (config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
return -1;
data = (data & ~(0xffff << ((where & 3) << 3))) |
(val << ((where & 3) << 3));
if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
return -1;
return PCIBIOS_SUCCESSFUL;
}
static int
write_config_dword(struct pci_bus *bus, unsigned int devfn, int where,
u32 val)
{
if (config_access(PCI_ACCESS_WRITE, bus, devfn, where, &val))
return -1;
return PCIBIOS_SUCCESSFUL;
}
static int config_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 * val)
{
switch (size) {
case 1: {
u8 _val;
int rc = read_config_byte(bus, devfn, where, &_val);
*val = _val;
return rc;
}
case 2: {
u16 _val;
int rc = read_config_word(bus, devfn, where, &_val);
*val = _val;
return rc;
}
default:
return read_config_dword(bus, devfn, where, val);
}
}
static int config_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
switch (size) {
case 1:
return write_config_byte(bus, devfn, where, (u8) val);
case 2:
return write_config_word(bus, devfn, where, (u16) val);
default:
return write_config_dword(bus, devfn, where, val);
}
}
struct pci_ops au1x_pci_ops = {
config_read,
config_write
};