numachip.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.
*
* Numascale NumaConnect-specific PCI code
*
* Copyright (C) 2012 Numascale AS. All rights reserved.
*
* Send feedback to <support@numascale.com>
*
* PCI accessor functions derived from mmconfig_64.c
*
*/
#include <linux/pci.h>
#include <asm/pci_x86.h>
static u8 limit __read_mostly;
static inline char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
{
struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
if (cfg && cfg->virt)
return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
return NULL;
}
static int pci_mmcfg_read_numachip(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 *value)
{
char __iomem *addr;
/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
err: *value = -1;
return -EINVAL;
}
/* Ensure AMD Northbridges don't decode reads to other devices */
if (unlikely(bus == 0 && devfn >= limit)) {
*value = -1;
return 0;
}
rcu_read_lock();
addr = pci_dev_base(seg, bus, devfn);
if (!addr) {
rcu_read_unlock();
goto err;
}
switch (len) {
case 1:
*value = mmio_config_readb(addr + reg);
break;
case 2:
*value = mmio_config_readw(addr + reg);
break;
case 4:
*value = mmio_config_readl(addr + reg);
break;
}
rcu_read_unlock();
return 0;
}
static int pci_mmcfg_write_numachip(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 value)
{
char __iomem *addr;
/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
return -EINVAL;
/* Ensure AMD Northbridges don't decode writes to other devices */
if (unlikely(bus == 0 && devfn >= limit))
return 0;
rcu_read_lock();
addr = pci_dev_base(seg, bus, devfn);
if (!addr) {
rcu_read_unlock();
return -EINVAL;
}
switch (len) {
case 1:
mmio_config_writeb(addr + reg, value);
break;
case 2:
mmio_config_writew(addr + reg, value);
break;
case 4:
mmio_config_writel(addr + reg, value);
break;
}
rcu_read_unlock();
return 0;
}
const struct pci_raw_ops pci_mmcfg_numachip = {
.read = pci_mmcfg_read_numachip,
.write = pci_mmcfg_write_numachip,
};
int __init pci_numachip_init(void)
{
int ret = 0;
u32 val;
/* For remote I/O, restrict bus 0 access to the actual number of AMD
Northbridges, which starts at device number 0x18 */
ret = raw_pci_read(0, 0, PCI_DEVFN(0x18, 0), 0x60, sizeof(val), &val);
if (ret)
goto out;
/* HyperTransport fabric size in bits 6:4 */
limit = PCI_DEVFN(0x18 + ((val >> 4) & 7) + 1, 0);
/* Use NumaChip PCI accessors for non-extended and extended access */
raw_pci_ops = raw_pci_ext_ops = &pci_mmcfg_numachip;
out:
return ret;
}