drm/i915/guc: Add GuC css header parser

The size / offset information of all firmware ingredients are
now caculated from header. Driver will validate the header and
rsa key size. If any component is out of boundary, driver will
reject the loading too.

v6: Clean up warnings from make docs

v5: Tidy up GuC titles in kernel/Doc

v4: Now using 'size_dw' for those defined in css_header

v3: 1) Move DOC to intel_guc_fwif.h right before css_header
definition. Add more comments.
    2) Change 'size' to 'len' or 'length' to avoid confusion.
    3) Add UOS_RSA_SCRATCH_MAX_COUNT according to BSpec. And
driver validate size of RSA key now.
    4) Add fw component size/offset info to intel_guc_fw.

v2: Add indent into DOC to make fixed-width format rather than
change the tmpl.

v1: 1) guc_css_header is defined as __packed now
    2) Add and correct GuC related topics in kernel/Doc

Signed-off-by: Alex Dai <yu.dai@intel.com>
Reviewed-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 59 insertions, 36 deletions

diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index ac31696012df..c0281df52702 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -31,7 +31,7 @@
 #include "intel_guc.h"
 
 /**
- * DOC: GuC
+ * DOC: GuC-specific firmware loader
  *
  * intel_guc:
  * Top level structure of guc. It handles firmware loading and manages client
@@ -208,16 +208,6 @@ static inline bool guc_ucode_response(struct drm_i915_private *dev_priv,
 /*
  * Transfer the firmware image to RAM for execution by the microcontroller.
  *
- * GuC Firmware layout:
- * +-------------------------------+  ----
- * |          CSS header           |  128B
- * | contains major/minor version  |
- * +-------------------------------+  ----
- * |             uCode             |
- * +-------------------------------+  ----
- * |         RSA signature         |  256B
- * +-------------------------------+  ----
- *
  * Architecturally, the DMA engine is bidirectional, and can potentially even
  * transfer between GTT locations. This functionality is left out of the API
  * for now as there is no need for it.
@@ -225,33 +215,29 @@ static inline bool guc_ucode_response(struct drm_i915_private *dev_priv,
  * Note that GuC needs the CSS header plus uKernel code to be copied by the
  * DMA engine in one operation, whereas the RSA signature is loaded via MMIO.
  */
-
-#define UOS_CSS_HEADER_OFFSET		0
-#define UOS_VER_MINOR_OFFSET		0x44
-#define UOS_VER_MAJOR_OFFSET		0x46
-#define UOS_CSS_HEADER_SIZE		0x80
-#define UOS_RSA_SIG_SIZE		0x100
-
 static int guc_ucode_xfer_dma(struct drm_i915_private *dev_priv)
 {
 	struct intel_guc_fw *guc_fw = &dev_priv->guc.guc_fw;
 	struct drm_i915_gem_object *fw_obj = guc_fw->guc_fw_obj;
 	unsigned long offset;
 	struct sg_table *sg = fw_obj->pages;
-	u32 status, ucode_size, rsa[UOS_RSA_SIG_SIZE / sizeof(u32)];
+	u32 status, rsa[UOS_RSA_SCRATCH_MAX_COUNT];
 	int i, ret = 0;
 
-	/* uCode size, also is where RSA signature starts */
-	offset = ucode_size = guc_fw->guc_fw_size - UOS_RSA_SIG_SIZE;
-	I915_WRITE(DMA_COPY_SIZE, ucode_size);
+	/* where RSA signature starts */
+	offset = guc_fw->rsa_offset;
 
 	/* Copy RSA signature from the fw image to HW for verification */
-	sg_pcopy_to_buffer(sg->sgl, sg->nents, rsa, UOS_RSA_SIG_SIZE, offset);
-	for (i = 0; i < UOS_RSA_SIG_SIZE / sizeof(u32); i++)
+	sg_pcopy_to_buffer(sg->sgl, sg->nents, rsa, sizeof(rsa), offset);
+	for (i = 0; i < UOS_RSA_SCRATCH_MAX_COUNT; i++)
 		I915_WRITE(UOS_RSA_SCRATCH(i), rsa[i]);
 
+	/* The header plus uCode will be copied to WOPCM via DMA, excluding any
+	 * other components */
+	I915_WRITE(DMA_COPY_SIZE, guc_fw->header_size + guc_fw->ucode_size);
+
 	/* Set the source address for the new blob */
-	offset = i915_gem_obj_ggtt_offset(fw_obj);
+	offset = i915_gem_obj_ggtt_offset(fw_obj) + guc_fw->header_offset;
 	I915_WRITE(DMA_ADDR_0_LOW, lower_32_bits(offset));
 	I915_WRITE(DMA_ADDR_0_HIGH, upper_32_bits(offset) & 0xFFFF);
 
@@ -457,10 +443,8 @@ static void guc_fw_fetch(struct drm_device *dev, struct intel_guc_fw *guc_fw)
 {
 	struct drm_i915_gem_object *obj;
 	const struct firmware *fw;
-	const u8 *css_header;
-	const size_t minsize = UOS_CSS_HEADER_SIZE + UOS_RSA_SIG_SIZE;
-	const size_t maxsize = GUC_WOPCM_SIZE_VALUE + UOS_RSA_SIG_SIZE
-			- 0x8000; /* 32k reserved (8K stack + 24k context) */
+	struct guc_css_header *css;
+	size_t size;
 	int err;
 
 	DRM_DEBUG_DRIVER("before requesting firmware: GuC fw fetch status %s\n",
@@ -474,12 +458,52 @@ static void guc_fw_fetch(struct drm_device *dev, struct intel_guc_fw *guc_fw)
 
 	DRM_DEBUG_DRIVER("fetch GuC fw from %s succeeded, fw %p\n",
 		guc_fw->guc_fw_path, fw);
-	DRM_DEBUG_DRIVER("firmware file size %zu (minimum %zu, maximum %zu)\n",
-		fw->size, minsize, maxsize);
 
-	/* Check the size of the blob befoe examining buffer contents */
-	if (fw->size < minsize || fw->size > maxsize)
+	/* Check the size of the blob before examining buffer contents */
+	if (fw->size < sizeof(struct guc_css_header)) {
+		DRM_ERROR("Firmware header is missing\n");
 		goto fail;
+	}
+
+	css = (struct guc_css_header *)fw->data;
+
+	/* Firmware bits always start from header */
+	guc_fw->header_offset = 0;
+	guc_fw->header_size = (css->header_size_dw - css->modulus_size_dw -
+		css->key_size_dw - css->exponent_size_dw) * sizeof(u32);
+
+	if (guc_fw->header_size != sizeof(struct guc_css_header)) {
+		DRM_ERROR("CSS header definition mismatch\n");
+		goto fail;
+	}
+
+	/* then, uCode */
+	guc_fw->ucode_offset = guc_fw->header_offset + guc_fw->header_size;
+	guc_fw->ucode_size = (css->size_dw - css->header_size_dw) * sizeof(u32);
+
+	/* now RSA */
+	if (css->key_size_dw != UOS_RSA_SCRATCH_MAX_COUNT) {
+		DRM_ERROR("RSA key size is bad\n");
+		goto fail;
+	}
+	guc_fw->rsa_offset = guc_fw->ucode_offset + guc_fw->ucode_size;
+	guc_fw->rsa_size = css->key_size_dw * sizeof(u32);
+
+	/* At least, it should have header, uCode and RSA. Size of all three. */
+	size = guc_fw->header_size + guc_fw->ucode_size + guc_fw->rsa_size;
+	if (fw->size < size) {
+		DRM_ERROR("Missing firmware components\n");
+		goto fail;
+	}
+
+	/* Header and uCode will be loaded to WOPCM. Size of the two. */
+	size = guc_fw->header_size + guc_fw->ucode_size;
+
+	/* Top 32k of WOPCM is reserved (8K stack + 24k RC6 context). */
+	if (size > GUC_WOPCM_SIZE_VALUE - 0x8000) {
+		DRM_ERROR("Firmware is too large to fit in WOPCM\n");
+		goto fail;
+	}
 
 	/*
 	 * The GuC firmware image has the version number embedded at a well-known
@@ -487,9 +511,8 @@ static void guc_fw_fetch(struct drm_device *dev, struct intel_guc_fw *guc_fw)
 	 * TWO bytes each (i.e. u16), although all pointers and offsets are defined
 	 * in terms of bytes (u8).
 	 */
-	css_header = fw->data + UOS_CSS_HEADER_OFFSET;
-	guc_fw->guc_fw_major_found = *(u16 *)(css_header + UOS_VER_MAJOR_OFFSET);
-	guc_fw->guc_fw_minor_found = *(u16 *)(css_header + UOS_VER_MINOR_OFFSET);
+	guc_fw->guc_fw_major_found = css->guc_sw_version >> 16;
+	guc_fw->guc_fw_minor_found = css->guc_sw_version & 0xFFFF;
 
 	if (guc_fw->guc_fw_major_found != guc_fw->guc_fw_major_wanted ||
 	    guc_fw->guc_fw_minor_found < guc_fw->guc_fw_minor_wanted) {