ACPI / nouveau: replace open-coded _DSM code with helper functions

Use helper functions to simplify _DSM related code in nouveau driver.
After analyzing the ACPI _DSM related code, I changed nouveau_optimus_dsm()
to expect a buffer and nouveau_dsm() to expect an integer only.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 54 insertions, 130 deletions

diff --git a/drivers/gpu/drm/nouveau/core/subdev/mxm/base.c b/drivers/gpu/drm/nouveau/core/subdev/mxm/base.c
index 129120473f6c..13c5af88a601 100644
--- a/drivers/gpu/drm/nouveau/core/subdev/mxm/base.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/mxm/base.c
@@ -87,55 +87,39 @@ mxm_shadow_dsm(struct nouveau_mxm *mxm, u8 version)
                 0xB8, 0x9C, 0x79, 0xB6, 0x2F, 0xD5, 0x56, 0x65
         };
         u32 mxms_args[] = { 0x00000000 };
-        union acpi_object args[4] = {
-                /* _DSM MUID */
-                { .buffer.type = 3,
-                  .buffer.length = sizeof(muid),
-                  .buffer.pointer = muid,
-                },
-                /* spec says this can be zero to mean "highest revision", but
-                 * of course there's at least one bios out there which fails
-                 * unless you pass in exactly the version it supports..
-                 */
-                { .integer.type = ACPI_TYPE_INTEGER,
-                  .integer.value = (version & 0xf0) << 4 | (version & 0x0f),
-                },
-                /* MXMS function */
-                { .integer.type = ACPI_TYPE_INTEGER,
-                  .integer.value = 0x00000010,
-                },
-                /* Pointer to MXMS arguments */
-                { .buffer.type = ACPI_TYPE_BUFFER,
-                  .buffer.length = sizeof(mxms_args),
-                  .buffer.pointer = (char *)mxms_args,
-                },
+        union acpi_object argv4 = {
+                .buffer.type = ACPI_TYPE_BUFFER,
+                .buffer.length = sizeof(mxms_args),
+                .buffer.pointer = (char *)mxms_args,
         };
-        struct acpi_object_list list = { ARRAY_SIZE(args), args };
-        struct acpi_buffer retn = { ACPI_ALLOCATE_BUFFER, NULL };
         union acpi_object *obj;
         acpi_handle handle;
-        int ret;
+        int rev;
 
         handle = ACPI_HANDLE(&device->pdev->dev);
         if (!handle)
                 return false;
 
-        ret = acpi_evaluate_object(handle, "_DSM", &list, &retn);
-        if (ret) {
-                nv_debug(mxm, "DSM MXMS failed: %d\n", ret);
+        /*
+         * spec says this can be zero to mean "highest revision", but
+         * of course there's at least one bios out there which fails
+         * unless you pass in exactly the version it supports..
+         */
+        rev = (version & 0xf0) << 4 | (version & 0x0f);
+        obj = acpi_evaluate_dsm(handle, muid, rev, 0x00000010, &argv4);
+        if (!obj) {
+                nv_debug(mxm, "DSM MXMS failed\n");
                 return false;
         }
 
-        obj = retn.pointer;
         if (obj->type == ACPI_TYPE_BUFFER) {
                 mxm->mxms = kmemdup(obj->buffer.pointer,
                                          obj->buffer.length, GFP_KERNEL);
-        } else
-        if (obj->type == ACPI_TYPE_INTEGER) {
+        } else if (obj->type == ACPI_TYPE_INTEGER) {
                 nv_debug(mxm, "DSM MXMS returned 0x%llx\n", obj->integer.value);
         }
 
-        kfree(obj);
+        ACPI_FREE(obj);
         return mxm->mxms != NULL;
 }
 #endif
diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 3f721e317fef..879a8b474bfe 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -78,127 +78,66 @@ static const char nouveau_op_dsm_muid[] = {
 
 static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t *result)
 {
-        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
-        struct acpi_object_list input;
-        union acpi_object params[4];
+        int i;
         union acpi_object *obj;
-        int i, err;
         char args_buff[4];
+        union acpi_object argv4 = {
+                .buffer.type = ACPI_TYPE_BUFFER,
+                .buffer.length = 4,
+                .buffer.pointer = args_buff
+        };
 
-        input.count = 4;
-        input.pointer = params;
-        params[0].type = ACPI_TYPE_BUFFER;
-        params[0].buffer.length = sizeof(nouveau_op_dsm_muid);
-        params[0].buffer.pointer = (char *)nouveau_op_dsm_muid;
-        params[1].type = ACPI_TYPE_INTEGER;
-        params[1].integer.value = 0x00000100;
-        params[2].type = ACPI_TYPE_INTEGER;
-        params[2].integer.value = func;
-        params[3].type = ACPI_TYPE_BUFFER;
-        params[3].buffer.length = 4;
         /* ACPI is little endian, AABBCCDD becomes {DD,CC,BB,AA} */
         for (i = 0; i < 4; i++)
                 args_buff[i] = (arg >> i * 8) & 0xFF;
-        params[3].buffer.pointer = args_buff;
 
-        err = acpi_evaluate_object(handle, "_DSM", &input, &output);
-        if (err) {
-                printk(KERN_INFO "failed to evaluate _DSM: %d\n", err);
-                return err;
-        }
-
-        obj = (union acpi_object *)output.pointer;
-
-        if (obj->type == ACPI_TYPE_INTEGER)
-                if (obj->integer.value == 0x80000002) {
-                        kfree(output.pointer);
-                        return -ENODEV;
-                }
-
-        if (obj->type == ACPI_TYPE_BUFFER) {
-                if (obj->buffer.length == 4 && result) {
-                        *result = 0;
+        *result = 0;
+        obj = acpi_evaluate_dsm_typed(handle, nouveau_op_dsm_muid, 0x00000100,
+                                      func, &argv4, ACPI_TYPE_BUFFER);
+        if (!obj) {
+                acpi_handle_info(handle, "failed to evaluate _DSM\n");
+                return AE_ERROR;
+        } else {
+                if (obj->buffer.length == 4) {
                         *result |= obj->buffer.pointer[0];
                         *result |= (obj->buffer.pointer[1] << 8);
                         *result |= (obj->buffer.pointer[2] << 16);
                         *result |= (obj->buffer.pointer[3] << 24);
                 }
+                ACPI_FREE(obj);
         }
 
-        kfree(output.pointer);
         return 0;
 }
 
-static int nouveau_dsm(acpi_handle handle, int func, int arg, uint32_t *result)
+static int nouveau_dsm(acpi_handle handle, int func, int arg)
 {
-        struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
-        struct acpi_object_list input;
-        union acpi_object params[4];
+        int ret = 0;
         union acpi_object *obj;
-        int err;
-
-        input.count = 4;
-        input.pointer = params;
-        params[0].type = ACPI_TYPE_BUFFER;
-        params[0].buffer.length = sizeof(nouveau_dsm_muid);
-        params[0].buffer.pointer = (char *)nouveau_dsm_muid;
-        params[1].type = ACPI_TYPE_INTEGER;
-        params[1].integer.value = 0x00000102;
-        params[2].type = ACPI_TYPE_INTEGER;
-        params[2].integer.value = func;
-        params[3].type = ACPI_TYPE_INTEGER;
-        params[3].integer.value = arg;
-
-        err = acpi_evaluate_object(handle, "_DSM", &input, &output);
-        if (err) {
-                printk(KERN_INFO "failed to evaluate _DSM: %d\n", err);
-                return err;
-        }
-
-        obj = (union acpi_object *)output.pointer;
-
-        if (obj->type == ACPI_TYPE_INTEGER)
-                if (obj->integer.value == 0x80000002) {
-                        kfree(output.pointer);
-                        return -ENODEV;
-                }
-
-        if (obj->type == ACPI_TYPE_BUFFER) {
-                if (obj->buffer.length == 4 && result) {
-                        *result = 0;
-                        *result |= obj->buffer.pointer[0];
-                        *result |= (obj->buffer.pointer[1] << 8);
-                        *result |= (obj->buffer.pointer[2] << 16);
-                        *result |= (obj->buffer.pointer[3] << 24);
-                }
+        union acpi_object argv4 = {
+                .integer.type = ACPI_TYPE_INTEGER,
+                .integer.value = arg,
+        };
+
+        obj = acpi_evaluate_dsm_typed(handle, nouveau_dsm_muid, 0x00000102,
+                                      func, &argv4, ACPI_TYPE_INTEGER);
+        if (!obj) {
+                acpi_handle_info(handle, "failed to evaluate _DSM\n");
+                return AE_ERROR;
+        } else {
+                if (obj->integer.value == 0x80000002)
+                        ret = -ENODEV;
+                ACPI_FREE(obj);
         }
 
-        kfree(output.pointer);
-        return 0;
-}
-
-/* Returns 1 if a DSM function is usable and 0 otherwise */
-static int nouveau_test_dsm(acpi_handle test_handle,
-        int (*dsm_func)(acpi_handle, int, int, uint32_t *),
-        int sfnc)
-{
-        u32 result = 0;
-
-        /* Function 0 returns a Buffer containing available functions. The args
-         * parameter is ignored for function 0, so just put 0 in it */
-        if (dsm_func(test_handle, 0, 0, &result))
-                return 0;
-
-        /* ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported. If
-         * the n-th bit is enabled, function n is supported */
-        return result & 1 && result & (1 << sfnc);
+        return ret;
 }
 
 static int nouveau_dsm_switch_mux(acpi_handle handle, int mux_id)
 {
         mxm_wmi_call_mxmx(mux_id == NOUVEAU_DSM_LED_STAMINA ? MXM_MXDS_ADAPTER_IGD : MXM_MXDS_ADAPTER_0);
         mxm_wmi_call_mxds(mux_id == NOUVEAU_DSM_LED_STAMINA ? MXM_MXDS_ADAPTER_IGD : MXM_MXDS_ADAPTER_0);
-        return nouveau_dsm(handle, NOUVEAU_DSM_LED, mux_id, NULL);
+        return nouveau_dsm(handle, NOUVEAU_DSM_LED, mux_id);
 }
 
 static int nouveau_dsm_set_discrete_state(acpi_handle handle, enum vga_switcheroo_state state)
@@ -208,7 +147,7 @@ static int nouveau_dsm_set_discrete_state(acpi_handle handle, enum vga_switchero
                 arg = NOUVEAU_DSM_POWER_SPEED;
         else
                 arg = NOUVEAU_DSM_POWER_STAMINA;
-        nouveau_dsm(handle, NOUVEAU_DSM_POWER, arg, NULL);
+        nouveau_dsm(handle, NOUVEAU_DSM_POWER, arg);
         return 0;
 }
 
@@ -268,11 +207,12 @@ static int nouveau_dsm_pci_probe(struct pci_dev *pdev)
                 nouveau_dsm_priv.other_handle = dhandle;
                 return false;
         }
-        if (nouveau_test_dsm(dhandle, nouveau_dsm, NOUVEAU_DSM_POWER))
+        if (acpi_check_dsm(dhandle, nouveau_dsm_muid, 0x00000102,
+                           1 << NOUVEAU_DSM_POWER))
                 retval |= NOUVEAU_DSM_HAS_MUX;
 
-        if (nouveau_test_dsm(dhandle, nouveau_optimus_dsm,
-                NOUVEAU_DSM_OPTIMUS_CAPS))
+        if (acpi_check_dsm(dhandle, nouveau_op_dsm_muid, 0x00000100,
+                           1 << NOUVEAU_DSM_OPTIMUS_CAPS))
                 retval |= NOUVEAU_DSM_HAS_OPT;
 
         if (retval & NOUVEAU_DSM_HAS_OPT) {