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 <linux/acpi.h>
  27 #include <asm/sal.h>
  28
  29 MODULE_AUTHOR("Bjorn Helgaas <bjorn.helgaas@hp.com>");
  30 MODULE_LICENSE("GPL");
  31 MODULE_DESCRIPTION("ACPI opregion handler for native firmware calls");
  32
  33 static bool force_register;
  34 module_param_named(force, force_register, bool, 0);
  35 MODULE_PARM_DESC(force, "Install opregion handler even without HPQ5001 device");
  36
  37 #define AML_NFW_SPACE           0xA1
  38
  39 struct ia64_pdesc {
  40         void *ip;
  41         void *gp;
  42 };
  43
  44 /*
  45  * N.B.  The layout of this structure is defined in the HP SPPA FW EAS, and
  46  *       the member offsets are embedded in AML methods.
  47  */
  48 struct ia64_nfw_context {
  49         u64 arg[8];
  50         struct ia64_sal_retval ret;
  51         u64 ip;
  52         u64 gp;
  53         u64 pad[2];
  54 };
  55
  56 static void *virt_map(u64 address)
  57 {
  58         if (address & (1UL << 63))
  59                 return (void *) (__IA64_UNCACHED_OFFSET | address);
  60
  61         return __va(address);
  62 }
  63
  64 static void aml_nfw_execute(struct ia64_nfw_context *c)
  65 {
  66         struct ia64_pdesc virt_entry;
  67         ia64_sal_handler entry;
  68
  69         virt_entry.ip = virt_map(c->ip);
  70         virt_entry.gp = virt_map(c->gp);
  71
  72         entry = (ia64_sal_handler) &virt_entry;
  73
  74         IA64_FW_CALL(entry, c->ret,
  75                      c->arg[0], c->arg[1], c->arg[2], c->arg[3],
  76                      c->arg[4], c->arg[5], c->arg[6], c->arg[7]);
  77 }
  78
  79 static void aml_nfw_read_arg(u8 *offset, u32 bit_width, u64 *value)
  80 {
  81         switch (bit_width) {
  82         case 8:
  83                 *value = *(u8 *)offset;
  84                 break;
  85         case 16:
  86                 *value = *(u16 *)offset;
  87                 break;
  88         case 32:
  89                 *value = *(u32 *)offset;
  90                 break;
  91         case 64:
  92                 *value = *(u64 *)offset;
  93                 break;
  94         }
  95 }
  96
  97 static void aml_nfw_write_arg(u8 *offset, u32 bit_width, u64 *value)
  98 {
  99         switch (bit_width) {
 100         case 8:
 101                 *(u8 *) offset = *value;
 102                 break;
 103         case 16:
 104                 *(u16 *) offset = *value;
 105                 break;
 106         case 32:
 107                 *(u32 *) offset = *value;
 108                 break;
 109         case 64:
 110                 *(u64 *) offset = *value;
 111                 break;
 112         }
 113 }
 114
 115 static acpi_status aml_nfw_handler(u32 function, acpi_physical_address address,
 116         u32 bit_width, u64 *value, void *handler_context,
 117         void *region_context)
 118 {
 119         struct ia64_nfw_context *context = handler_context;
 120         u8 *offset = (u8 *) context + address;
 121
 122         if (bit_width !=  8 && bit_width != 16 &&
 123             bit_width != 32 && bit_width != 64)
 124                 return AE_BAD_PARAMETER;
 125
 126         if (address + (bit_width >> 3) > sizeof(struct ia64_nfw_context))
 127                 return AE_BAD_PARAMETER;
 128
 129         switch (function) {
 130         case ACPI_READ:
 131                 if (address == offsetof(struct ia64_nfw_context, ret))
 132                         aml_nfw_execute(context);
 133                 aml_nfw_read_arg(offset, bit_width, value);
 134                 break;
 135         case ACPI_WRITE:
 136                 aml_nfw_write_arg(offset, bit_width, value);
 137                 break;
 138         }
 139
 140         return AE_OK;
 141 }
 142
 143 static struct ia64_nfw_context global_context;
 144 static int global_handler_registered;
 145
 146 static int aml_nfw_add_global_handler(void)
 147 {
 148         acpi_status status;
 149
 150         if (global_handler_registered)
 151                 return 0;
 152
 153         status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
 154                 AML_NFW_SPACE, aml_nfw_handler, NULL, &global_context);
 155         if (ACPI_FAILURE(status))
 156                 return -ENODEV;
 157
 158         global_handler_registered = 1;
 159         printk(KERN_INFO "Global 0x%02X opregion handler registered\n",
 160                 AML_NFW_SPACE);
 161         return 0;
 162 }
 163
 164 static int aml_nfw_remove_global_handler(void)
 165 {
 166         acpi_status status;
 167
 168         if (!global_handler_registered)
 169                 return 0;
 170
 171         status = acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
 172                 AML_NFW_SPACE, aml_nfw_handler);
 173         if (ACPI_FAILURE(status))
 174                 return -ENODEV;
 175
 176         global_handler_registered = 0;
 177         printk(KERN_INFO "Global 0x%02X opregion handler removed\n",
 178                 AML_NFW_SPACE);
 179         return 0;
 180 }
 181
 182 static int aml_nfw_add(struct acpi_device *device)
 183 {
 184         /*
 185          * We would normally allocate a new context structure and install
 186          * the address space handler for the specific device we found.
 187          * But the HP-UX implementation shares a single global context
 188          * and always puts the handler at the root, so we'll do the same.
 189          */
 190         return aml_nfw_add_global_handler();
 191 }
 192
 193 static int aml_nfw_remove(struct acpi_device *device)
 194 {
 195         return aml_nfw_remove_global_handler();
 196 }
 197
 198 static const struct acpi_device_id aml_nfw_ids[] = {
 199         {"HPQ5001", 0},
 200         {"", 0}
 201 };
 202
 203 static struct acpi_driver acpi_aml_nfw_driver = {
 204         .name = "native firmware",
 205         .ids = aml_nfw_ids,
 206         .ops = {
 207                 .add = aml_nfw_add,
 208                 .remove = aml_nfw_remove,
 209                 },
 210 };
 211
 212 static int __init aml_nfw_init(void)
 213 {
 214         int result;
 215
 216         if (force_register)
 217                 aml_nfw_add_global_handler();
 218
 219         result = acpi_bus_register_driver(&acpi_aml_nfw_driver);
 220         if (result < 0) {
 221                 aml_nfw_remove_global_handler();
 222                 return result;
 223         }
 224
 225         return 0;
 226 }
 227
 228 static void __exit aml_nfw_exit(void)
 229 {
 230         acpi_bus_unregister_driver(&acpi_aml_nfw_driver);
 231         aml_nfw_remove_global_handler();
 232 }
 233
 234 module_init(aml_nfw_init);
 235 module_exit(aml_nfw_exit);