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core_t2.c

/*
 *    linux/arch/alpha/kernel/core_t2.c
 *
 * Written by Jay A Estabrook (jestabro@amt.tay1.dec.com).
 * December 1996.
 *
 * based on CIA code by David A Rusling (david.rusling@reo.mts.dec.com)
 *
 * Code common to all T2 core logic chips.
 */

#define __EXTERN_INLINE
#include <asm/io.h>
#include <asm/core_t2.h>
#undef __EXTERN_INLINE

#include <linux/types.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/init.h>

#include <asm/ptrace.h>
#include <asm/delay.h>

#include "proto.h"
#include "pci_impl.h"

/* For dumping initial DMA window settings. */
#define DEBUG_PRINT_INITIAL_SETTINGS 0

/* For dumping final DMA window settings. */
#define DEBUG_PRINT_FINAL_SETTINGS 0

/*
 * By default, we direct-map starting at 2GB, in order to allow the
 * maximum size direct-map window (2GB) to match the maximum amount of
 * memory (2GB) that can be present on SABLEs. But that limits the
 * floppy to DMA only via the scatter/gather window set up for 8MB
 * ISA DMA, since the maximum ISA DMA address is 2GB-1.
 *
 * For now, this seems a reasonable trade-off: even though most SABLEs
 * have less than 1GB of memory, floppy usage/performance will not
 * really be affected by forcing it to go via scatter/gather...
 */
#define T2_DIRECTMAP_2G 1

#if T2_DIRECTMAP_2G
# define T2_DIRECTMAP_START   0x80000000UL
# define T2_DIRECTMAP_LENGTH  0x80000000UL
#else
# define T2_DIRECTMAP_START   0x40000000UL
# define T2_DIRECTMAP_LENGTH  0x40000000UL
#endif

/* The ISA scatter/gather window settings. */
#define T2_ISA_SG_START       0x00800000UL
#define T2_ISA_SG_LENGTH      0x00800000UL

/*
 * NOTE: Herein lie back-to-back mb instructions.  They are magic. 
 * One plausible explanation is that the i/o controller does not properly
 * handle the system transaction.  Another involves timing.  Ho hum.
 */

/*
 * BIOS32-style PCI interface:
 */

#define DEBUG_CONFIG 0

#if DEBUG_CONFIG
# define DBG(args)      printk args
#else
# define DBG(args)
#endif

static volatile unsigned int t2_mcheck_any_expected;
static volatile unsigned int t2_mcheck_last_taken;

/* Place to save the DMA Window registers as set up by SRM
   for restoration during shutdown. */
static struct
{
      struct {
            unsigned long wbase;
            unsigned long wmask;
            unsigned long tbase;
      } window[2];
      unsigned long hae_1;
      unsigned long hae_2;
      unsigned long hae_3;
      unsigned long hae_4;
      unsigned long hbase;
} t2_saved_config __attribute((common));

/*
 * Given a bus, device, and function number, compute resulting
 * configuration space address and setup the T2_HAXR2 register
 * accordingly.  It is therefore not safe to have concurrent
 * invocations to configuration space access routines, but there
 * really shouldn't be any need for this.
 *
 * Type 0:
 *
 *  3 3|3 3 2 2|2 2 2 2|2 2 2 2|1 1 1 1|1 1 1 1|1 1 
 *  3 2|1 0 9 8|7 6 5 4|3 2 1 0|9 8 7 6|5 4 3 2|1 0 9 8|7 6 5 4|3 2 1 0
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * | | |D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|D|F|F|F|R|R|R|R|R|R|0|0|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 *    31:11 Device select bit.
 *    10:8  Function number
 *     7:2  Register number
 *
 * Type 1:
 *
 *  3 3|3 3 2 2|2 2 2 2|2 2 2 2|1 1 1 1|1 1 1 1|1 1 
 *  3 2|1 0 9 8|7 6 5 4|3 2 1 0|9 8 7 6|5 4 3 2|1 0 9 8|7 6 5 4|3 2 1 0
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * | | | | | | | | | | |B|B|B|B|B|B|B|B|D|D|D|D|D|F|F|F|R|R|R|R|R|R|0|1|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 *    31:24 reserved
 *    23:16 bus number (8 bits = 128 possible buses)
 *    15:11 Device number (5 bits)
 *    10:8  function number
 *     7:2  register number
 *  
 * Notes:
 *    The function number selects which function of a multi-function device 
 *    (e.g., SCSI and Ethernet).
 * 
 *    The register selects a DWORD (32 bit) register offset.  Hence it
 *    doesn't get shifted by 2 bits as we want to "drop" the bottom two
 *    bits.
 */

static int
mk_conf_addr(struct pci_bus *pbus, unsigned int device_fn, int where,
           unsigned long *pci_addr, unsigned char *type1)
{
      unsigned long addr;
      u8 bus = pbus->number;

      DBG(("mk_conf_addr(bus=%d, dfn=0x%x, where=0x%x,"
           " addr=0x%lx, type1=0x%x)\n",
           bus, device_fn, where, pci_addr, type1));

      if (bus == 0) {
            int device = device_fn >> 3;

            /* Type 0 configuration cycle.  */

            if (device > 8) {
                  DBG(("mk_conf_addr: device (%d)>20, returning -1\n",
                       device));
                  return -1;
            }

            *type1 = 0;
            addr = (0x0800L << device) | ((device_fn & 7) << 8) | (where);
      } else {
            /* Type 1 configuration cycle.  */
            *type1 = 1;
            addr = (bus << 16) | (device_fn << 8) | (where);
      }
      *pci_addr = addr;
      DBG(("mk_conf_addr: returning pci_addr 0x%lx\n", addr));
      return 0;
}

/*
 * NOTE: both conf_read() and conf_write() may set HAE_3 when needing
 *       to do type1 access. This is protected by the use of spinlock IRQ
 *       primitives in the wrapper functions pci_{read,write}_config_*()
 *       defined in drivers/pci/pci.c.
 */
static unsigned int
conf_read(unsigned long addr, unsigned char type1)
{
      unsigned int value, cpu, taken;
      unsigned long t2_cfg = 0;

      cpu = smp_processor_id();

      DBG(("conf_read(addr=0x%lx, type1=%d)\n", addr, type1));

      /* If Type1 access, must set T2 CFG.  */
      if (type1) {
            t2_cfg = *(vulp)T2_HAE_3 & ~0xc0000000UL;
            *(vulp)T2_HAE_3 = 0x40000000UL | t2_cfg;
            mb();
      }
      mb();
      draina();

      mcheck_expected(cpu) = 1;
      mcheck_taken(cpu) = 0;
      t2_mcheck_any_expected |= (1 << cpu);
      mb();

      /* Access configuration space. */
      value = *(vuip)addr;
      mb();
      mb();  /* magic */

      /* Wait for possible mcheck. Also, this lets other CPUs clear
         their mchecks as well, as they can reliably tell when
         another CPU is in the midst of handling a real mcheck via
         the "taken" function. */
      udelay(100);

      if ((taken = mcheck_taken(cpu))) {
            mcheck_taken(cpu) = 0;
            t2_mcheck_last_taken |= (1 << cpu);
            value = 0xffffffffU;
            mb();
      }
      mcheck_expected(cpu) = 0;
      t2_mcheck_any_expected = 0;
      mb();

      /* If Type1 access, must reset T2 CFG so normal IO space ops work.  */
      if (type1) {
            *(vulp)T2_HAE_3 = t2_cfg;
            mb();
      }

      return value;
}

static void
conf_write(unsigned long addr, unsigned int value, unsigned char type1)
{
      unsigned int cpu, taken;
      unsigned long t2_cfg = 0;

      cpu = smp_processor_id();

      /* If Type1 access, must set T2 CFG.  */
      if (type1) {
            t2_cfg = *(vulp)T2_HAE_3 & ~0xc0000000UL;
            *(vulp)T2_HAE_3 = t2_cfg | 0x40000000UL;
            mb();
      }
      mb();
      draina();

      mcheck_expected(cpu) = 1;
      mcheck_taken(cpu) = 0;
      t2_mcheck_any_expected |= (1 << cpu);
      mb();

      /* Access configuration space.  */
      *(vuip)addr = value;
      mb();
      mb();  /* magic */

      /* Wait for possible mcheck. Also, this lets other CPUs clear
         their mchecks as well, as they can reliably tell when
         this CPU is in the midst of handling a real mcheck via
         the "taken" function. */
      udelay(100);

      if ((taken = mcheck_taken(cpu))) {
            mcheck_taken(cpu) = 0;
            t2_mcheck_last_taken |= (1 << cpu);
            mb();
      }
      mcheck_expected(cpu) = 0;
      t2_mcheck_any_expected = 0;
      mb();

      /* If Type1 access, must reset T2 CFG so normal IO space ops work.  */
      if (type1) {
            *(vulp)T2_HAE_3 = t2_cfg;
            mb();
      }
}

static int
t2_read_config(struct pci_bus *bus, unsigned int devfn, int where,
             int size, u32 *value)
{
      unsigned long addr, pci_addr;
      unsigned char type1;
      int shift;
      long mask;

      if (mk_conf_addr(bus, devfn, where, &pci_addr, &type1))
            return PCIBIOS_DEVICE_NOT_FOUND;

      mask = (size - 1) * 8;
      shift = (where & 3) * 8;
      addr = (pci_addr << 5) + mask + T2_CONF;
      *value = conf_read(addr, type1) >> (shift);
      return PCIBIOS_SUCCESSFUL;
}

static int 
t2_write_config(struct pci_bus *bus, unsigned int devfn, int where, int size,
            u32 value)
{
      unsigned long addr, pci_addr;
      unsigned char type1;
      long mask;

      if (mk_conf_addr(bus, devfn, where, &pci_addr, &type1))
            return PCIBIOS_DEVICE_NOT_FOUND;

      mask = (size - 1) * 8;
      addr = (pci_addr << 5) + mask + T2_CONF;
      conf_write(addr, value << ((where & 3) * 8), type1);
      return PCIBIOS_SUCCESSFUL;
}

struct pci_ops t2_pci_ops = 
{
      .read =           t2_read_config,
      .write =    t2_write_config,
};

static void __init
t2_direct_map_window1(unsigned long base, unsigned long length)
{
      unsigned long temp;

      __direct_map_base = base;
      __direct_map_size = length;

      temp = (base & 0xfff00000UL) | ((base + length - 1) >> 20);
      *(vulp)T2_WBASE1 = temp | 0x80000UL; /* OR in ENABLE bit */
      temp = (length - 1) & 0xfff00000UL;
      *(vulp)T2_WMASK1 = temp;
      *(vulp)T2_TBASE1 = 0;

#if DEBUG_PRINT_FINAL_SETTINGS
      printk("%s: setting WBASE1=0x%lx WMASK1=0x%lx TBASE1=0x%lx\n",
             __func__, *(vulp)T2_WBASE1, *(vulp)T2_WMASK1, *(vulp)T2_TBASE1);
#endif
}

static void __init
t2_sg_map_window2(struct pci_controller *hose,
              unsigned long base,
              unsigned long length)
{
      unsigned long temp;

      /* Note we can only do 1 SG window, as the other is for direct, so
         do an ISA SG area, especially for the floppy. */
      hose->sg_isa = iommu_arena_new(hose, base, length, 0);
      hose->sg_pci = NULL;

      temp = (base & 0xfff00000UL) | ((base + length - 1) >> 20);
      *(vulp)T2_WBASE2 = temp | 0xc0000UL; /* OR in ENABLE/SG bits */
      temp = (length - 1) & 0xfff00000UL;
      *(vulp)T2_WMASK2 = temp;
      *(vulp)T2_TBASE2 = virt_to_phys(hose->sg_isa->ptes) >> 1;
      mb();

      t2_pci_tbi(hose, 0, -1); /* flush TLB all */

#if DEBUG_PRINT_FINAL_SETTINGS
      printk("%s: setting WBASE2=0x%lx WMASK2=0x%lx TBASE2=0x%lx\n",
             __func__, *(vulp)T2_WBASE2, *(vulp)T2_WMASK2, *(vulp)T2_TBASE2);
#endif
}

static void __init
t2_save_configuration(void)
{
#if DEBUG_PRINT_INITIAL_SETTINGS
      printk("%s: HAE_1 was 0x%lx\n", __func__, srm_hae); /* HW is 0 */
      printk("%s: HAE_2 was 0x%lx\n", __func__, *(vulp)T2_HAE_2);
      printk("%s: HAE_3 was 0x%lx\n", __func__, *(vulp)T2_HAE_3);
      printk("%s: HAE_4 was 0x%lx\n", __func__, *(vulp)T2_HAE_4);
      printk("%s: HBASE was 0x%lx\n", __func__, *(vulp)T2_HBASE);

      printk("%s: WBASE1=0x%lx WMASK1=0x%lx TBASE1=0x%lx\n", __func__,
             *(vulp)T2_WBASE1, *(vulp)T2_WMASK1, *(vulp)T2_TBASE1);
      printk("%s: WBASE2=0x%lx WMASK2=0x%lx TBASE2=0x%lx\n", __func__,
             *(vulp)T2_WBASE2, *(vulp)T2_WMASK2, *(vulp)T2_TBASE2);
#endif

      /*
       * Save the DMA Window registers.
       */
      t2_saved_config.window[0].wbase = *(vulp)T2_WBASE1;
      t2_saved_config.window[0].wmask = *(vulp)T2_WMASK1;
      t2_saved_config.window[0].tbase = *(vulp)T2_TBASE1;
      t2_saved_config.window[1].wbase = *(vulp)T2_WBASE2;
      t2_saved_config.window[1].wmask = *(vulp)T2_WMASK2;
      t2_saved_config.window[1].tbase = *(vulp)T2_TBASE2;

      t2_saved_config.hae_1 = srm_hae; /* HW is already set to 0 */
      t2_saved_config.hae_2 = *(vulp)T2_HAE_2;
      t2_saved_config.hae_3 = *(vulp)T2_HAE_3;
      t2_saved_config.hae_4 = *(vulp)T2_HAE_4;
      t2_saved_config.hbase = *(vulp)T2_HBASE;
}

void __init
t2_init_arch(void)
{
      struct pci_controller *hose;
      struct resource *hae_mem;
      unsigned long temp;
      unsigned int i;

      for (i = 0; i < NR_CPUS; i++) {
            mcheck_expected(i) = 0;
            mcheck_taken(i) = 0;
      }
      t2_mcheck_any_expected = 0;
      t2_mcheck_last_taken = 0;

      /* Enable scatter/gather TLB use.  */
      temp = *(vulp)T2_IOCSR;
      if (!(temp & (0x1UL << 26))) {
            printk("t2_init_arch: enabling SG TLB, IOCSR was 0x%lx\n",
                   temp);
            *(vulp)T2_IOCSR = temp | (0x1UL << 26);
            mb(); 
            *(vulp)T2_IOCSR; /* read it back to make sure */
      }

      t2_save_configuration();

      /*
       * Create our single hose.
       */
      pci_isa_hose = hose = alloc_pci_controller();
      hose->io_space = &ioport_resource;
      hae_mem = alloc_resource();
      hae_mem->start = 0;
      hae_mem->end = T2_MEM_R1_MASK;
      hae_mem->name = pci_hae0_name;
      if (request_resource(&iomem_resource, hae_mem) < 0)
            printk(KERN_ERR "Failed to request HAE_MEM\n");
      hose->mem_space = hae_mem;
      hose->index = 0;

      hose->sparse_mem_base = T2_SPARSE_MEM - IDENT_ADDR;
      hose->dense_mem_base = T2_DENSE_MEM - IDENT_ADDR;
      hose->sparse_io_base = T2_IO - IDENT_ADDR;
      hose->dense_io_base = 0;

      /*
       * Set up the PCI->physical memory translation windows.
       *
       * Window 1 is direct mapped.
       * Window 2 is scatter/gather (for ISA).
       */

      t2_direct_map_window1(T2_DIRECTMAP_START, T2_DIRECTMAP_LENGTH);

      /* Always make an ISA DMA window. */
      t2_sg_map_window2(hose, T2_ISA_SG_START, T2_ISA_SG_LENGTH);

      *(vulp)T2_HBASE = 0x0; /* Disable HOLES. */

      /* Zero HAE.  */
      *(vulp)T2_HAE_1 = 0; mb(); /* Sparse MEM HAE */
      *(vulp)T2_HAE_2 = 0; mb(); /* Sparse I/O HAE */
      *(vulp)T2_HAE_3 = 0; mb(); /* Config Space HAE */

      /*
       * We also now zero out HAE_4, the dense memory HAE, so that
       * we need not account for its "offset" when accessing dense
       * memory resources which we allocated in our normal way. This
       * HAE would need to stay untouched were we to keep the SRM
       * resource settings.
       *
       * Thus we can now run standard X servers on SABLE/LYNX. :-)
       */
      *(vulp)T2_HAE_4 = 0; mb();
}

void
t2_kill_arch(int mode)
{
      /*
       * Restore the DMA Window registers.
       */
      *(vulp)T2_WBASE1 = t2_saved_config.window[0].wbase;
      *(vulp)T2_WMASK1 = t2_saved_config.window[0].wmask;
      *(vulp)T2_TBASE1 = t2_saved_config.window[0].tbase;
      *(vulp)T2_WBASE2 = t2_saved_config.window[1].wbase;
      *(vulp)T2_WMASK2 = t2_saved_config.window[1].wmask;
      *(vulp)T2_TBASE2 = t2_saved_config.window[1].tbase;
      mb();

      *(vulp)T2_HAE_1 = srm_hae;
      *(vulp)T2_HAE_2 = t2_saved_config.hae_2;
      *(vulp)T2_HAE_3 = t2_saved_config.hae_3;
      *(vulp)T2_HAE_4 = t2_saved_config.hae_4;
      *(vulp)T2_HBASE = t2_saved_config.hbase;
      mb();
      *(vulp)T2_HBASE; /* READ it back to ensure WRITE occurred. */
}

void
t2_pci_tbi(struct pci_controller *hose, dma_addr_t start, dma_addr_t end)
{
      unsigned long t2_iocsr;

      t2_iocsr = *(vulp)T2_IOCSR;

      /* set the TLB Clear bit */
      *(vulp)T2_IOCSR = t2_iocsr | (0x1UL << 28);
      mb();
      *(vulp)T2_IOCSR; /* read it back to make sure */

      /* clear the TLB Clear bit */
      *(vulp)T2_IOCSR = t2_iocsr & ~(0x1UL << 28);
      mb();
      *(vulp)T2_IOCSR; /* read it back to make sure */
}

#define SIC_SEIC (1UL << 33)    /* System Event Clear */

static void
t2_clear_errors(int cpu)
{
      struct sable_cpu_csr *cpu_regs;

      cpu_regs = (struct sable_cpu_csr *)T2_CPUn_BASE(cpu);
            
      cpu_regs->sic &= ~SIC_SEIC;

      /* Clear CPU errors.  */
      cpu_regs->bcce |= cpu_regs->bcce;
      cpu_regs->cbe  |= cpu_regs->cbe;
      cpu_regs->bcue |= cpu_regs->bcue;
      cpu_regs->dter |= cpu_regs->dter;

      *(vulp)T2_CERR1 |= *(vulp)T2_CERR1;
      *(vulp)T2_PERR1 |= *(vulp)T2_PERR1;

      mb();
      mb();  /* magic */
}

/*
 * SABLE seems to have a "broadcast" style machine check, in that all
 * CPUs receive it. And, the issuing CPU, in the case of PCI Config
 * space read/write faults, will also receive a second mcheck, upon
 * lowering IPL during completion processing in pci_read_config_byte()
 * et al.
 *
 * Hence all the taken/expected/any_expected/last_taken stuff...
 */
void
t2_machine_check(unsigned long vector, unsigned long la_ptr)
{
      int cpu = smp_processor_id();
#ifdef CONFIG_VERBOSE_MCHECK
      struct el_common *mchk_header = (struct el_common *)la_ptr;
#endif

      /* Clear the error before any reporting.  */
      mb();
      mb();  /* magic */
      draina();
      t2_clear_errors(cpu);

      /* This should not actually be done until the logout frame is
         examined, but, since we don't do that, go on and do this... */
      wrmces(0x7);
      mb();

      /* Now, do testing for the anomalous conditions. */
      if (!mcheck_expected(cpu) && t2_mcheck_any_expected) {
            /*
             * FUNKY: Received mcheck on a CPU and not
             * expecting it, but another CPU is expecting one.
             *
             * Just dismiss it for now on this CPU...
             */
#ifdef CONFIG_VERBOSE_MCHECK
            if (alpha_verbose_mcheck > 1) {
                  printk("t2_machine_check(cpu%d): any_expected 0x%x -"
                         " (assumed) spurious -"
                         " code 0x%x\n", cpu, t2_mcheck_any_expected,
                         (unsigned int)mchk_header->code);
            }
#endif
            return;
      }

      if (!mcheck_expected(cpu) && !t2_mcheck_any_expected) {
            if (t2_mcheck_last_taken & (1 << cpu)) {
#ifdef CONFIG_VERBOSE_MCHECK
                if (alpha_verbose_mcheck > 1) {
                  printk("t2_machine_check(cpu%d): last_taken 0x%x - "
                         "unexpected mcheck - code 0x%x\n",
                         cpu, t2_mcheck_last_taken,
                         (unsigned int)mchk_header->code);
                }
#endif
                t2_mcheck_last_taken = 0;
                mb();
                return;
            } else {
                  t2_mcheck_last_taken = 0;
                  mb();
            }
      }

#ifdef CONFIG_VERBOSE_MCHECK
      if (alpha_verbose_mcheck > 1) {
            printk("%s t2_mcheck(cpu%d): last_taken 0x%x - "
                   "any_expected 0x%x - code 0x%x\n",
                   (mcheck_expected(cpu) ? "EX" : "UN"), cpu,
                   t2_mcheck_last_taken, t2_mcheck_any_expected,
                   (unsigned int)mchk_header->code);
      }
#endif

      process_mcheck_info(vector, la_ptr, "T2", mcheck_expected(cpu));
}

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