arch/mips/pci/pci-sb1250.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2001,2002,2003 Broadcom Corporation
   4  * Copyright (C) 2004 by Ralf Baechle (ralf@linux-mips.org)
   5  */
   6
   7 /*
   8  * BCM1250-specific PCI support
   9  *
  10  * This module provides the glue between Linux's PCI subsystem
  11  * and the hardware.  We basically provide glue for accessing
  12  * configuration space, and set up the translation for I/O
  13  * space accesses.
  14  *
  15  * To access configuration space, we use ioremap.  In the 32-bit
  16  * kernel, this consumes either 4 or 8 page table pages, and 16MB of
  17  * kernel mapped memory.  Hopefully neither of these should be a huge
  18  * problem.
  19  */
  20 #include <linux/types.h>
  21 #include <linux/pci.h>
  22 #include <linux/kernel.h>
  23 #include <linux/init.h>
  24 #include <linux/mm.h>
  25 #include <linux/console.h>
  26 #include <linux/tty.h>
  27 #include <linux/vt.h>
  28
  29 #include <asm/io.h>
  30
  31 #include <asm/sibyte/sb1250_defs.h>
  32 #include <asm/sibyte/sb1250_regs.h>
  33 #include <asm/sibyte/sb1250_scd.h>
  34 #include <asm/sibyte/board.h>
  35
  36 /*
  37  * Macros for calculating offsets into config space given a device
  38  * structure or dev/fun/reg
  39  */
  40 #define CFGOFFSET(bus, devfn, where) (((bus)<<16) + ((devfn)<<8) + (where))
  41 #define CFGADDR(bus, devfn, where)   CFGOFFSET((bus)->number, (devfn), where)
  42
  43 static void *cfg_space;
  44
  45 #define PCI_BUS_ENABLED 1
  46 #define LDT_BUS_ENABLED 2
  47 #define PCI_DEVICE_MODE 4
  48
  49 static int sb1250_bus_status;
  50
  51 #define PCI_BRIDGE_DEVICE  0
  52 #define LDT_BRIDGE_DEVICE  1
  53
  54 #ifdef CONFIG_SIBYTE_HAS_LDT
  55 /*
  56  * HT's level-sensitive interrupts require EOI, which is generated
  57  * through a 4MB memory-mapped region
  58  */
  59 unsigned long ldt_eoi_space;
  60 #endif
  61
  62 /*
  63  * Read/write 32-bit values in config space.
  64  */
  65 static inline u32 READCFG32(u32 addr)
  66 {
  67         return *(u32 *) (cfg_space + (addr & ~3));
  68 }
  69
  70 static inline void WRITECFG32(u32 addr, u32 data)
  71 {
  72         *(u32 *) (cfg_space + (addr & ~3)) = data;
  73 }
  74
  75 int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
  76 {
  77         return dev->irq;
  78 }
  79
  80 /* Do platform specific device initialization at pci_enable_device() time */
  81 int pcibios_plat_dev_init(struct pci_dev *dev)
  82 {
  83         return 0;
  84 }
  85
  86 /*
  87  * Some checks before doing config cycles:
  88  * In PCI Device Mode, hide everything on bus 0 except the LDT host
  89  * bridge.  Otherwise, access is controlled by bridge MasterEn bits.
  90  */
  91 static int sb1250_pci_can_access(struct pci_bus *bus, int devfn)
  92 {
  93         u32 devno;
  94
  95         if (!(sb1250_bus_status & (PCI_BUS_ENABLED | PCI_DEVICE_MODE)))
  96                 return 0;
  97
  98         if (bus->number == 0) {
  99                 devno = PCI_SLOT(devfn);
 100                 if (devno == LDT_BRIDGE_DEVICE)
 101                         return (sb1250_bus_status & LDT_BUS_ENABLED) != 0;
 102                 else if (sb1250_bus_status & PCI_DEVICE_MODE)
 103                         return 0;
 104                 else
 105                         return 1;
 106         } else
 107                 return 1;
 108 }
 109
 110 /*
 111  * Read/write access functions for various sizes of values
 112  * in config space.  Return all 1's for disallowed accesses
 113  * for a kludgy but adequate simulation of master aborts.
 114  */
 115
 116 static int sb1250_pcibios_read(struct pci_bus *bus, unsigned int devfn,
 117                                int where, int size, u32 * val)
 118 {
 119         u32 data = 0;
 120
 121         if ((size == 2) && (where & 1))
 122                 return PCIBIOS_BAD_REGISTER_NUMBER;
 123         else if ((size == 4) && (where & 3))
 124                 return PCIBIOS_BAD_REGISTER_NUMBER;
 125
 126         if (sb1250_pci_can_access(bus, devfn))
 127                 data = READCFG32(CFGADDR(bus, devfn, where));
 128         else
 129                 data = 0xFFFFFFFF;
 130
 131         if (size == 1)
 132                 *val = (data >> ((where & 3) << 3)) & 0xff;
 133         else if (size == 2)
 134                 *val = (data >> ((where & 3) << 3)) & 0xffff;
 135         else
 136                 *val = data;
 137
 138         return PCIBIOS_SUCCESSFUL;
 139 }
 140
 141 static int sb1250_pcibios_write(struct pci_bus *bus, unsigned int devfn,
 142                                 int where, int size, u32 val)
 143 {
 144         u32 cfgaddr = CFGADDR(bus, devfn, where);
 145         u32 data = 0;
 146
 147         if ((size == 2) && (where & 1))
 148                 return PCIBIOS_BAD_REGISTER_NUMBER;
 149         else if ((size == 4) && (where & 3))
 150                 return PCIBIOS_BAD_REGISTER_NUMBER;
 151
 152         if (!sb1250_pci_can_access(bus, devfn))
 153                 return PCIBIOS_BAD_REGISTER_NUMBER;
 154
 155         data = READCFG32(cfgaddr);
 156
 157         if (size == 1)
 158                 data = (data & ~(0xff << ((where & 3) << 3))) |
 159                     (val << ((where & 3) << 3));
 160         else if (size == 2)
 161                 data = (data & ~(0xffff << ((where & 3) << 3))) |
 162                     (val << ((where & 3) << 3));
 163         else
 164                 data = val;
 165
 166         WRITECFG32(cfgaddr, data);
 167
 168         return PCIBIOS_SUCCESSFUL;
 169 }
 170
 171 struct pci_ops sb1250_pci_ops = {
 172         .read   = sb1250_pcibios_read,
 173         .write  = sb1250_pcibios_write,
 174 };
 175
 176 static struct resource sb1250_mem_resource = {
 177         .name   = "SB1250 PCI MEM",
 178         .start  = 0x40000000UL,
 179         .end    = 0x5fffffffUL,
 180         .flags  = IORESOURCE_MEM,
 181 };
 182
 183 static struct resource sb1250_io_resource = {
 184         .name   = "SB1250 PCI I/O",
 185         .start  = 0x00000000UL,
 186         .end    = 0x01ffffffUL,
 187         .flags  = IORESOURCE_IO,
 188 };
 189
 190 struct pci_controller sb1250_controller = {
 191         .pci_ops        = &sb1250_pci_ops,
 192         .mem_resource   = &sb1250_mem_resource,
 193         .io_resource    = &sb1250_io_resource,
 194 };
 195
 196 static int __init sb1250_pcibios_init(void)
 197 {
 198         void __iomem *io_map_base;
 199         uint32_t cmdreg;
 200         uint64_t reg;
 201
 202         /* CFE will assign PCI resources */
 203         pci_set_flags(PCI_PROBE_ONLY);
 204
 205         /* Avoid ISA compat ranges.  */
 206         PCIBIOS_MIN_IO = 0x00008000UL;
 207         PCIBIOS_MIN_MEM = 0x01000000UL;
 208
 209         /* Set I/O resource limits.  */
 210         ioport_resource.end = 0x01ffffffUL;     /* 32MB accessible by sb1250 */
 211         iomem_resource.end = 0xffffffffUL;      /* no HT support yet */
 212
 213         cfg_space =
 214             ioremap(A_PHYS_LDTPCI_CFG_MATCH_BITS, 16 * 1024 * 1024);
 215
 216         /*
 217          * See if the PCI bus has been configured by the firmware.
 218          */
 219         reg = __raw_readq(IOADDR(A_SCD_SYSTEM_CFG));
 220         if (!(reg & M_SYS_PCI_HOST)) {
 221                 sb1250_bus_status |= PCI_DEVICE_MODE;
 222         } else {
 223                 cmdreg =
 224                     READCFG32(CFGOFFSET
 225                               (0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0),
 226                                PCI_COMMAND));
 227                 if (!(cmdreg & PCI_COMMAND_MASTER)) {
 228                         printk
 229                             ("PCI: Skipping PCI probe.  Bus is not initialized.\n");
 230                         iounmap(cfg_space);
 231                         return 0;
 232                 }
 233                 sb1250_bus_status |= PCI_BUS_ENABLED;
 234         }
 235
 236         /*
 237          * Establish mappings in KSEG2 (kernel virtual) to PCI I/O
 238          * space.  Use "match bytes" policy to make everything look
 239          * little-endian.  So, you need to also set
 240          * CONFIG_SWAP_IO_SPACE, but this is the combination that
 241          * works correctly with most of Linux's drivers.
 242          * XXX ehs: Should this happen in PCI Device mode?
 243          */
 244         io_map_base = ioremap(A_PHYS_LDTPCI_IO_MATCH_BYTES, 1024 * 1024);
 245         sb1250_controller.io_map_base = (unsigned long)io_map_base;
 246         set_io_port_base((unsigned long)io_map_base);
 247
 248 #ifdef CONFIG_SIBYTE_HAS_LDT
 249         /*
 250          * Also check the LDT bridge's enable, just in case we didn't
 251          * initialize that one.
 252          */
 253
 254         cmdreg = READCFG32(CFGOFFSET(0, PCI_DEVFN(LDT_BRIDGE_DEVICE, 0),
 255                                      PCI_COMMAND));
 256         if (cmdreg & PCI_COMMAND_MASTER) {
 257                 sb1250_bus_status |= LDT_BUS_ENABLED;
 258
 259                 /*
 260                  * Need bits 23:16 to convey vector number.  Note that
 261                  * this consumes 4MB of kernel-mapped memory
 262                  * (Kseg2/Kseg3) for 32-bit kernel.
 263                  */
 264                 ldt_eoi_space = (unsigned long)
 265                     ioremap(A_PHYS_LDT_SPECIAL_MATCH_BYTES,
 266                             4 * 1024 * 1024);
 267         }
 268 #endif
 269
 270         register_pci_controller(&sb1250_controller);
 271
 272 #ifdef CONFIG_VGA_CONSOLE
 273         console_lock();
 274         do_take_over_console(&vga_con, 0, MAX_NR_CONSOLES - 1, 1);
 275         console_unlock();
 276 #endif
 277         return 0;
 278 }
 279 arch_initcall(sb1250_pcibios_init);