arch/ia64/hp/common/aml_nfw.c

   1 /*
   2  * OpRegion handler to allow AML to call native firmware
   3  *
   4  * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
   5  *      Bjorn Helgaas <bjorn.helgaas@hp.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This driver implements HP Open Source Review Board proposal 1842,
  12  * which was approved on 9/20/2006.
  13  *
  14  * For technical documentation, see the HP SPPA Firmware EAS, Appendix F.
  15  *
  16  * ACPI does not define a mechanism for AML methods to call native firmware
  17  * interfaces such as PAL or SAL.  This OpRegion handler adds such a mechanism.
  18  * After the handler is installed, an AML method can call native firmware by
  19  * storing the arguments and firmware entry point to specific offsets in the
  20  * OpRegion.  When AML reads the "return value" offset from the OpRegion, this
  21  * handler loads up the arguments, makes the firmware call, and returns the
  22  * result.
  23  */
  24
  25 #include <linux/module.h>
  26 #include <acpi/acpi_bus.h>
  27 #include <acpi/acpi_drivers.h>
  28 #include <asm/sal.h>
  29
  30 MODULE_AUTHOR("Bjorn Helgaas <bjorn.helgaas@hp.com>");
  31 MODULE_LICENSE("GPL");
  32 MODULE_DESCRIPTION("ACPI opregion handler for native firmware calls");
  33
  34 static bool force_register;
  35 module_param_named(force, force_register, bool, 0);
  36 MODULE_PARM_DESC(force, "Install opregion handler even without HPQ5001 device");
  37
  38 #define AML_NFW_SPACE           0xA1
  39
  40 struct ia64_pdesc {
  41         void *ip;
  42         void *gp;
  43 };
  44
  45 /*
  46  * N.B.  The layout of this structure is defined in the HP SPPA FW EAS, and
  47  *       the member offsets are embedded in AML methods.
  48  */
  49 struct ia64_nfw_context {
  50         u64 arg[8];
  51         struct ia64_sal_retval ret;
  52         u64 ip;
  53         u64 gp;
  54         u64 pad[2];
  55 };
  56
  57 static void *virt_map(u64 address)
  58 {
  59         if (address & (1UL << 63))
  60                 return (void *) (__IA64_UNCACHED_OFFSET | address);
  61
  62         return __va(address);
  63 }
  64
  65 static void aml_nfw_execute(struct ia64_nfw_context *c)
  66 {
  67         struct ia64_pdesc virt_entry;
  68         ia64_sal_handler entry;
  69
  70         virt_entry.ip = virt_map(c->ip);
  71         virt_entry.gp = virt_map(c->gp);
  72
  73         entry = (ia64_sal_handler) &virt_entry;
  74
  75         IA64_FW_CALL(entry, c->ret,
  76                      c->arg[0], c->arg[1], c->arg[2], c->arg[3],
  77                      c->arg[4], c->arg[5], c->arg[6], c->arg[7]);
  78 }
  79
  80 static void aml_nfw_read_arg(u8 *offset, u32 bit_width, u64 *value)
  81 {
  82         switch (bit_width) {
  83         case 8:
  84                 *value = *(u8 *)offset;
  85                 break;
  86         case 16:
  87                 *value = *(u16 *)offset;
  88                 break;
  89         case 32:
  90                 *value = *(u32 *)offset;
  91                 break;
  92         case 64:
  93                 *value = *(u64 *)offset;
  94                 break;
  95         }
  96 }
  97
  98 static void aml_nfw_write_arg(u8 *offset, u32 bit_width, u64 *value)
  99 {
 100         switch (bit_width) {
 101         case 8:
 102                 *(u8 *) offset = *value;
 103                 break;
 104         case 16:
 105                 *(u16 *) offset = *value;
 106                 break;
 107         case 32:
 108                 *(u32 *) offset = *value;
 109                 break;
 110         case 64:
 111                 *(u64 *) offset = *value;
 112                 break;
 113         }
 114 }
 115
 116 static acpi_status aml_nfw_handler(u32 function, acpi_physical_address address,
 117         u32 bit_width, u64 *value, void *handler_context,
 118         void *region_context)
 119 {
 120         struct ia64_nfw_context *context = handler_context;
 121         u8 *offset = (u8 *) context + address;
 122
 123         if (bit_width !=  8 && bit_width != 16 &&
 124             bit_width != 32 && bit_width != 64)
 125                 return AE_BAD_PARAMETER;
 126
 127         if (address + (bit_width >> 3) > sizeof(struct ia64_nfw_context))
 128                 return AE_BAD_PARAMETER;
 129
 130         switch (function) {
 131         case ACPI_READ:
 132                 if (address == offsetof(struct ia64_nfw_context, ret))
 133                         aml_nfw_execute(context);
 134                 aml_nfw_read_arg(offset, bit_width, value);
 135                 break;
 136         case ACPI_WRITE:
 137                 aml_nfw_write_arg(offset, bit_width, value);
 138                 break;
 139         }
 140
 141         return AE_OK;
 142 }
 143
 144 static struct ia64_nfw_context global_context;
 145 static int global_handler_registered;
 146
 147 static int aml_nfw_add_global_handler(void)
 148 {
 149         acpi_status status;
 150
 151         if (global_handler_registered)
 152                 return 0;
 153
 154         status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
 155                 AML_NFW_SPACE, aml_nfw_handler, NULL, &global_context);
 156         if (ACPI_FAILURE(status))
 157                 return -ENODEV;
 158
 159         global_handler_registered = 1;
 160         printk(KERN_INFO "Global 0x%02X opregion handler registered\n",
 161                 AML_NFW_SPACE);
 162         return 0;
 163 }
 164
 165 static int aml_nfw_remove_global_handler(void)
 166 {
 167         acpi_status status;
 168
 169         if (!global_handler_registered)
 170                 return 0;
 171
 172         status = acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
 173                 AML_NFW_SPACE, aml_nfw_handler);
 174         if (ACPI_FAILURE(status))
 175                 return -ENODEV;
 176
 177         global_handler_registered = 0;
 178         printk(KERN_INFO "Global 0x%02X opregion handler removed\n",
 179                 AML_NFW_SPACE);
 180         return 0;
 181 }
 182
 183 static int aml_nfw_add(struct acpi_device *device)
 184 {
 185         /*
 186          * We would normally allocate a new context structure and install
 187          * the address space handler for the specific device we found.
 188          * But the HP-UX implementation shares a single global context
 189          * and always puts the handler at the root, so we'll do the same.
 190          */
 191         return aml_nfw_add_global_handler();
 192 }
 193
 194 static int aml_nfw_remove(struct acpi_device *device)
 195 {
 196         return aml_nfw_remove_global_handler();
 197 }
 198
 199 static const struct acpi_device_id aml_nfw_ids[] = {
 200         {"HPQ5001", 0},
 201         {"", 0}
 202 };
 203
 204 static struct acpi_driver acpi_aml_nfw_driver = {
 205         .name = "native firmware",
 206         .ids = aml_nfw_ids,
 207         .ops = {
 208                 .add = aml_nfw_add,
 209                 .remove = aml_nfw_remove,
 210                 },
 211 };
 212
 213 static int __init aml_nfw_init(void)
 214 {
 215         int result;
 216
 217         if (force_register)
 218                 aml_nfw_add_global_handler();
 219
 220         result = acpi_bus_register_driver(&acpi_aml_nfw_driver);
 221         if (result < 0) {
 222                 aml_nfw_remove_global_handler();
 223                 return result;
 224         }
 225
 226         return 0;
 227 }
 228
 229 static void __exit aml_nfw_exit(void)
 230 {
 231         acpi_bus_unregister_driver(&acpi_aml_nfw_driver);
 232         aml_nfw_remove_global_handler();
 233 }
 234
 235 module_init(aml_nfw_init);
 236 module_exit(aml_nfw_exit);