arch/powerpc/kernel/io-workarounds.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Support PCI IO workaround
   4  *
   5  *  Copyright (C) 2006 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   6  *                     IBM, Corp.
   7  *  (C) Copyright 2007-2008 TOSHIBA CORPORATION
   8  */
   9 #undef DEBUG
  10
  11 #include <linux/kernel.h>
  12 #include <linux/sched/mm.h>     /* for init_mm */
  13 #include <linux/pgtable.h>
  14
  15 #include <asm/io.h>
  16 #include <asm/machdep.h>
  17 #include <asm/ppc-pci.h>
  18 #include <asm/io-workarounds.h>
  19 #include <asm/pte-walk.h>
  20
  21
  22 #define IOWA_MAX_BUS    8
  23
  24 static struct iowa_bus iowa_busses[IOWA_MAX_BUS];
  25 static unsigned int iowa_bus_count;
  26
  27 static struct iowa_bus *iowa_pci_find(unsigned long vaddr, unsigned long paddr)
  28 {
  29         int i, j;
  30         struct resource *res;
  31         unsigned long vstart, vend;
  32
  33         for (i = 0; i < iowa_bus_count; i++) {
  34                 struct iowa_bus *bus = &iowa_busses[i];
  35                 struct pci_controller *phb = bus->phb;
  36
  37                 if (vaddr) {
  38                         vstart = (unsigned long)phb->io_base_virt;
  39                         vend = vstart + phb->pci_io_size - 1;
  40                         if ((vaddr >= vstart) && (vaddr <= vend))
  41                                 return bus;
  42                 }
  43
  44                 if (paddr)
  45                         for (j = 0; j < 3; j++) {
  46                                 res = &phb->mem_resources[j];
  47                                 if (paddr >= res->start && paddr <= res->end)
  48                                         return bus;
  49                         }
  50         }
  51
  52         return NULL;
  53 }
  54
  55 #ifdef CONFIG_PPC_INDIRECT_MMIO
  56 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
  57 {
  58         unsigned hugepage_shift;
  59         struct iowa_bus *bus;
  60         int token;
  61
  62         token = PCI_GET_ADDR_TOKEN(addr);
  63
  64         if (token && token <= iowa_bus_count)
  65                 bus = &iowa_busses[token - 1];
  66         else {
  67                 unsigned long vaddr, paddr;
  68                 pte_t *ptep;
  69
  70                 vaddr = (unsigned long)PCI_FIX_ADDR(addr);
  71                 if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
  72                         return NULL;
  73                 /*
  74                  * We won't find huge pages here (iomem). Also can't hit
  75                  * a page table free due to init_mm
  76                  */
  77                 ptep = find_init_mm_pte(vaddr, &hugepage_shift);
  78                 if (ptep == NULL)
  79                         paddr = 0;
  80                 else {
  81                         WARN_ON(hugepage_shift);
  82                         paddr = pte_pfn(*ptep) << PAGE_SHIFT;
  83                 }
  84                 bus = iowa_pci_find(vaddr, paddr);
  85
  86                 if (bus == NULL)
  87                         return NULL;
  88         }
  89
  90         return bus;
  91 }
  92 #else /* CONFIG_PPC_INDIRECT_MMIO */
  93 struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
  94 {
  95         return NULL;
  96 }
  97 #endif /* !CONFIG_PPC_INDIRECT_MMIO */
  98
  99 #ifdef CONFIG_PPC_INDIRECT_PIO
 100 struct iowa_bus *iowa_pio_find_bus(unsigned long port)
 101 {
 102         unsigned long vaddr = (unsigned long)pci_io_base + port;
 103         return iowa_pci_find(vaddr, 0);
 104 }
 105 #else
 106 struct iowa_bus *iowa_pio_find_bus(unsigned long port)
 107 {
 108         return NULL;
 109 }
 110 #endif
 111
 112 #define DEF_PCI_AC_RET(name, ret, at, al, space, aa)            \
 113 static ret iowa_##name at                                       \
 114 {                                                               \
 115         struct iowa_bus *bus;                                   \
 116         bus = iowa_##space##_find_bus(aa);                      \
 117         if (bus && bus->ops && bus->ops->name)                  \
 118                 return bus->ops->name al;                       \
 119         return __do_##name al;                                  \
 120 }
 121
 122 #define DEF_PCI_AC_NORET(name, at, al, space, aa)               \
 123 static void iowa_##name at                                      \
 124 {                                                               \
 125         struct iowa_bus *bus;                                   \
 126         bus = iowa_##space##_find_bus(aa);                      \
 127         if (bus && bus->ops && bus->ops->name) {                \
 128                 bus->ops->name al;                              \
 129                 return;                                         \
 130         }                                                       \
 131         __do_##name al;                                         \
 132 }
 133
 134 #include <asm/io-defs.h>
 135
 136 #undef DEF_PCI_AC_RET
 137 #undef DEF_PCI_AC_NORET
 138
 139 static const struct ppc_pci_io iowa_pci_io = {
 140
 141 #define DEF_PCI_AC_RET(name, ret, at, al, space, aa)    .name = iowa_##name,
 142 #define DEF_PCI_AC_NORET(name, at, al, space, aa)       .name = iowa_##name,
 143
 144 #include <asm/io-defs.h>
 145
 146 #undef DEF_PCI_AC_RET
 147 #undef DEF_PCI_AC_NORET
 148
 149 };
 150
 151 #ifdef CONFIG_PPC_INDIRECT_MMIO
 152 void __iomem *iowa_ioremap(phys_addr_t addr, unsigned long size,
 153                            pgprot_t prot, void *caller)
 154 {
 155         struct iowa_bus *bus;
 156         void __iomem *res = __ioremap_caller(addr, size, prot, caller);
 157         int busno;
 158
 159         bus = iowa_pci_find(0, (unsigned long)addr);
 160         if (bus != NULL) {
 161                 busno = bus - iowa_busses;
 162                 PCI_SET_ADDR_TOKEN(res, busno + 1);
 163         }
 164         return res;
 165 }
 166 #endif /* !CONFIG_PPC_INDIRECT_MMIO */
 167
 168 bool io_workaround_inited;
 169
 170 /* Enable IO workaround */
 171 static void io_workaround_init(void)
 172 {
 173         if (io_workaround_inited)
 174                 return;
 175         ppc_pci_io = iowa_pci_io;
 176         io_workaround_inited = true;
 177 }
 178
 179 /* Register new bus to support workaround */
 180 void iowa_register_bus(struct pci_controller *phb, struct ppc_pci_io *ops,
 181                        int (*initfunc)(struct iowa_bus *, void *), void *data)
 182 {
 183         struct iowa_bus *bus;
 184         struct device_node *np = phb->dn;
 185
 186         io_workaround_init();
 187
 188         if (iowa_bus_count >= IOWA_MAX_BUS) {
 189                 pr_err("IOWA:Too many pci bridges, "
 190                        "workarounds disabled for %pOF\n", np);
 191                 return;
 192         }
 193
 194         bus = &iowa_busses[iowa_bus_count];
 195         bus->phb = phb;
 196         bus->ops = ops;
 197         bus->private = data;
 198
 199         if (initfunc)
 200                 if ((*initfunc)(bus, data))
 201                         return;
 202
 203         iowa_bus_count++;
 204
 205         pr_debug("IOWA:[%d]Add bus, %pOF.\n", iowa_bus_count-1, np);
 206 }
 207