drivers/misc/sgi-xp/xp_sn2.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
   7  */
   8
   9 /*
  10  * Cross Partition (XP) sn2-based functions.
  11  *
  12  *      Architecture specific implementation of common functions.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <asm/sn/bte.h>
  18 #include <asm/sn/sn_sal.h>
  19 #include "xp.h"
  20
  21 /*
  22  * The export of xp_nofault_PIOR needs to happen here since it is defined
  23  * in drivers/misc/sgi-xp/xp_nofault.S. The target of the nofault read is
  24  * defined here.
  25  */
  26 EXPORT_SYMBOL_GPL(xp_nofault_PIOR);
  27
  28 u64 xp_nofault_PIOR_target;
  29 EXPORT_SYMBOL_GPL(xp_nofault_PIOR_target);
  30
  31 /*
  32  * Register a nofault code region which performs a cross-partition PIO read.
  33  * If the PIO read times out, the MCA handler will consume the error and
  34  * return to a kernel-provided instruction to indicate an error. This PIO read
  35  * exists because it is guaranteed to timeout if the destination is down
  36  * (amo operations do not timeout on at least some CPUs on Shubs <= v1.2,
  37  * which unfortunately we have to work around).
  38  */
  39 static enum xp_retval
  40 xp_register_nofault_code_sn2(void)
  41 {
  42         int ret;
  43         u64 func_addr;
  44         u64 err_func_addr;
  45
  46         func_addr = *(u64 *)xp_nofault_PIOR;
  47         err_func_addr = *(u64 *)xp_error_PIOR;
  48         ret = sn_register_nofault_code(func_addr, err_func_addr, err_func_addr,
  49                                        1, 1);
  50         if (ret != 0) {
  51                 dev_err(xp, "can't register nofault code, error=%d\n", ret);
  52                 return xpSalError;
  53         }
  54         /*
  55          * Setup the nofault PIO read target. (There is no special reason why
  56          * SH_IPI_ACCESS was selected.)
  57          */
  58         if (is_shub1())
  59                 xp_nofault_PIOR_target = SH1_IPI_ACCESS;
  60         else if (is_shub2())
  61                 xp_nofault_PIOR_target = SH2_IPI_ACCESS0;
  62
  63         return xpSuccess;
  64 }
  65
  66 static void
  67 xp_unregister_nofault_code_sn2(void)
  68 {
  69         u64 func_addr = *(u64 *)xp_nofault_PIOR;
  70         u64 err_func_addr = *(u64 *)xp_error_PIOR;
  71
  72         /* unregister the PIO read nofault code region */
  73         (void)sn_register_nofault_code(func_addr, err_func_addr,
  74                                        err_func_addr, 1, 0);
  75 }
  76
  77 /*
  78  * Convert a virtual memory address to a physical memory address.
  79  */
  80 static unsigned long
  81 xp_pa_sn2(void *addr)
  82 {
  83         return __pa(addr);
  84 }
  85
  86 /*
  87  * Wrapper for bte_copy().
  88  *
  89  *      dst_pa - physical address of the destination of the transfer.
  90  *      src_pa - physical address of the source of the transfer.
  91  *      len - number of bytes to transfer from source to destination.
  92  *
  93  * Note: xp_remote_memcpy_sn2() should never be called while holding a spinlock.
  94  */
  95 static enum xp_retval
  96 xp_remote_memcpy_sn2(unsigned long dst_pa, const unsigned long src_pa,
  97                      size_t len)
  98 {
  99         bte_result_t ret;
 100
 101         ret = bte_copy(src_pa, dst_pa, len, (BTE_NOTIFY | BTE_WACQUIRE), NULL);
 102         if (ret == BTE_SUCCESS)
 103                 return xpSuccess;
 104
 105         if (is_shub2()) {
 106                 dev_err(xp, "bte_copy() on shub2 failed, error=0x%x dst_pa="
 107                         "0x%016lx src_pa=0x%016lx len=%ld\\n", ret, dst_pa,
 108                         src_pa, len);
 109         } else {
 110                 dev_err(xp, "bte_copy() failed, error=%d dst_pa=0x%016lx "
 111                         "src_pa=0x%016lx len=%ld\\n", ret, dst_pa, src_pa, len);
 112         }
 113
 114         return xpBteCopyError;
 115 }
 116
 117 static int
 118 xp_cpu_to_nasid_sn2(int cpuid)
 119 {
 120         return cpuid_to_nasid(cpuid);
 121 }
 122
 123 enum xp_retval
 124 xp_init_sn2(void)
 125 {
 126         BUG_ON(!is_shub());
 127
 128         xp_max_npartitions = XP_MAX_NPARTITIONS_SN2;
 129         xp_partition_id = sn_partition_id;
 130         xp_region_size = sn_region_size;
 131
 132         xp_pa = xp_pa_sn2;
 133         xp_remote_memcpy = xp_remote_memcpy_sn2;
 134         xp_cpu_to_nasid = xp_cpu_to_nasid_sn2;
 135
 136         return xp_register_nofault_code_sn2();
 137 }
 138
 139 void
 140 xp_exit_sn2(void)
 141 {
 142         BUG_ON(!is_shub());
 143
 144         xp_unregister_nofault_code_sn2();
 145 }
 146