LXR linux/arch/x86/pci/numachip.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Numascale NumaConnect-specific PCI code
   4 *
   5 * Copyright (C) 2012 Numascale AS. All rights reserved.
   6 *
   7 * Send feedback to <support@numascale.com>
   8 *
   9 * PCI accessor functions derived from mmconfig_64.c
  10 *
  11 */
  12
  13#include <linux/pci.h>
  14#include <asm/pci_x86.h>
  15#include <asm/numachip/numachip.h>
  16
  17static u8 limit __read_mostly;
  18
  19static inline char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
  20{
  21        struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
  22
  23        if (cfg && cfg->virt)
  24                return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
  25        return NULL;
  26}
  27
  28static int pci_mmcfg_read_numachip(unsigned int seg, unsigned int bus,
  29                          unsigned int devfn, int reg, int len, u32 *value)
  30{
  31        char __iomem *addr;
  32
  33        /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  34        if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  35err:            *value = -1;
  36                return -EINVAL;
  37        }
  38
  39        /* Ensure AMD Northbridges don't decode reads to other devices */
  40        if (unlikely(bus == 0 && devfn >= limit)) {
  41                *value = -1;
  42                return 0;
  43        }
  44
  45        rcu_read_lock();
  46        addr = pci_dev_base(seg, bus, devfn);
  47        if (!addr) {
  48                rcu_read_unlock();
  49                goto err;
  50        }
  51
  52        switch (len) {
  53        case 1:
  54                *value = mmio_config_readb(addr + reg);
  55                break;
  56        case 2:
  57                *value = mmio_config_readw(addr + reg);
  58                break;
  59        case 4:
  60                *value = mmio_config_readl(addr + reg);
  61                break;
  62        }
  63        rcu_read_unlock();
  64
  65        return 0;
  66}
  67
  68static int pci_mmcfg_write_numachip(unsigned int seg, unsigned int bus,
  69                           unsigned int devfn, int reg, int len, u32 value)
  70{
  71        char __iomem *addr;
  72
  73        /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  74        if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  75                return -EINVAL;
  76
  77        /* Ensure AMD Northbridges don't decode writes to other devices */
  78        if (unlikely(bus == 0 && devfn >= limit))
  79                return 0;
  80
  81        rcu_read_lock();
  82        addr = pci_dev_base(seg, bus, devfn);
  83        if (!addr) {
  84                rcu_read_unlock();
  85                return -EINVAL;
  86        }
  87
  88        switch (len) {
  89        case 1:
  90                mmio_config_writeb(addr + reg, value);
  91                break;
  92        case 2:
  93                mmio_config_writew(addr + reg, value);
  94                break;
  95        case 4:
  96                mmio_config_writel(addr + reg, value);
  97                break;
  98        }
  99        rcu_read_unlock();
 100
 101        return 0;
 102}
 103
 104static const struct pci_raw_ops pci_mmcfg_numachip = {
 105        .read = pci_mmcfg_read_numachip,
 106        .write = pci_mmcfg_write_numachip,
 107};
 108
 109int __init pci_numachip_init(void)
 110{
 111        int ret = 0;
 112        u32 val;
 113
 114        /* For remote I/O, restrict bus 0 access to the actual number of AMD
 115           Northbridges, which starts at device number 0x18 */
 116        ret = raw_pci_read(0, 0, PCI_DEVFN(0x18, 0), 0x60, sizeof(val), &val);
 117        if (ret)
 118                goto out;
 119
 120        /* HyperTransport fabric size in bits 6:4 */
 121        limit = PCI_DEVFN(0x18 + ((val >> 4) & 7) + 1, 0);
 122
 123        /* Use NumaChip PCI accessors for non-extended and extended access */
 124        raw_pci_ops = raw_pci_ext_ops = &pci_mmcfg_numachip;
 125out:
 126        return ret;
 127}
 128