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>

Documentation/DocBook/drm.tmpl

@@ -4239,17 +4239,21 @@ int num_ioctls;</synopsis>
       </sect2>
     </sect1>
     <sect1>
-      <title>GuC-based Command Submission</title>
+      <title>GuC</title>
       <sect2>
-        <title>GuC</title>
+        <title>GuC-specific firmware loader</title>
 !Pdrivers/gpu/drm/i915/intel_guc_loader.c GuC-specific firmware loader
 !Idrivers/gpu/drm/i915/intel_guc_loader.c
       </sect2>
       <sect2>
-        <title>GuC Client</title>
-!Pdrivers/gpu/drm/i915/i915_guc_submission.c GuC-based command submissison
+        <title>GuC-based command submission</title>
+!Pdrivers/gpu/drm/i915/i915_guc_submission.c GuC-based command submission
 !Idrivers/gpu/drm/i915/i915_guc_submission.c
       </sect2>
+      <sect2>
+        <title>GuC Firmware Layout</title>
+!Pdrivers/gpu/drm/i915/intel_guc_fwif.h GuC Firmware Layout
+      </sect2>
     </sect1>
 
     <sect1>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2403,6 +2403,12 @@ static int i915_guc_load_status_info(struct seq_file *m, void *data)
 		guc_fw->guc_fw_major_wanted, guc_fw->guc_fw_minor_wanted);
 	seq_printf(m, "\tversion found: %d.%d\n",
 		guc_fw->guc_fw_major_found, guc_fw->guc_fw_minor_found);
+	seq_printf(m, "\theader: offset is %d; size = %d\n",
+		guc_fw->header_offset, guc_fw->header_size);
+	seq_printf(m, "\tuCode: offset is %d; size = %d\n",
+		guc_fw->ucode_offset, guc_fw->ucode_size);
+	seq_printf(m, "\tRSA: offset is %d; size = %d\n",
+		guc_fw->rsa_offset, guc_fw->rsa_size);
 
 	tmp = I915_READ(GUC_STATUS);
 

drivers/gpu/drm/i915/i915_guc_reg.h

@@ -42,6 +42,7 @@
 #define SOFT_SCRATCH(n)			(0xc180 + ((n) * 4))
 
 #define UOS_RSA_SCRATCH(i)		(0xc200 + (i) * 4)
+#define   UOS_RSA_SCRATCH_MAX_COUNT	  64
 #define DMA_ADDR_0_LOW			0xc300
 #define DMA_ADDR_0_HIGH			0xc304
 #define DMA_ADDR_1_LOW			0xc308

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -27,7 +27,7 @@
 #include "intel_guc.h"
 
 /**
- * DOC: GuC Client
+ * DOC: GuC-based command submission
  *
  * i915_guc_client:
  * We use the term client to avoid confusion with contexts. A i915_guc_client is
@@ -588,8 +588,7 @@ static void lr_context_update(struct drm_i915_gem_request *rq)
 /**
  * i915_guc_submit() - Submit commands through GuC
  * @client:	the guc client where commands will go through
- * @ctx:	LRC where commands come from
- * @ring:	HW engine that will excute the commands
+ * @rq:		request associated with the commands
  *
  * Return:	0 if succeed
  */
@@ -731,7 +730,8 @@ static void guc_client_free(struct drm_device *dev,
  * 		The kernel client to replace ExecList submission is created with
  * 		NORMAL priority. Priority of a client for scheduler can be HIGH,
  * 		while a preemption context can use CRITICAL.
- * @ctx		the context to own the client (we use the default render context)
+ * @ctx:	the context that owns the client (we use the default render
+ * 		context)
  *
  * Return:	An i915_guc_client object if success.
  */

drivers/gpu/drm/i915/intel_guc.h

@@ -76,11 +76,17 @@ struct intel_guc_fw {
 	uint16_t			guc_fw_minor_wanted;
 	uint16_t			guc_fw_major_found;
 	uint16_t			guc_fw_minor_found;
+
+	uint32_t header_size;
+	uint32_t header_offset;
+	uint32_t rsa_size;
+	uint32_t rsa_offset;
+	uint32_t ucode_size;
+	uint32_t ucode_offset;
 };
 
 struct intel_guc {
 	struct intel_guc_fw guc_fw;
-
 	uint32_t log_flags;
 	struct drm_i915_gem_object *log_obj;
 

drivers/gpu/drm/i915/intel_guc_fwif.h

@@ -122,6 +122,78 @@
 
 #define GUC_CTL_MAX_DWORDS		(GUC_CTL_RSRVD + 1)
 
+/**
+ * DOC: GuC Firmware Layout
+ *
+ * The GuC firmware layout looks like this:
+ *
+ *     +-------------------------------+
+ *     |        guc_css_header         |
+ *     | contains major/minor version  |
+ *     +-------------------------------+
+ *     |             uCode             |
+ *     +-------------------------------+
+ *     |         RSA signature         |
+ *     +-------------------------------+
+ *     |          modulus key          |
+ *     +-------------------------------+
+ *     |          exponent val         |
+ *     +-------------------------------+
+ *
+ * The firmware may or may not have modulus key and exponent data. The header,
+ * uCode and RSA signature are must-have components that will be used by driver.
+ * Length of each components, which is all in dwords, can be found in header.
+ * In the case that modulus and exponent are not present in fw, a.k.a truncated
+ * image, the length value still appears in header.
+ *
+ * Driver will do some basic fw size validation based on the following rules:
+ *
+ * 1. Header, uCode and RSA are must-have components.
+ * 2. All firmware components, if they present, are in the sequence illustrated
+ * in the layout table above.
+ * 3. Length info of each component can be found in header, in dwords.
+ * 4. Modulus and exponent key are not required by driver. They may not appear
+ * in fw. So driver will load a truncated firmware in this case.
+ */
+
+struct guc_css_header {
+	uint32_t module_type;
+	/* header_size includes all non-uCode bits, including css_header, rsa
+	 * key, modulus key and exponent data. */
+	uint32_t header_size_dw;
+	uint32_t header_version;
+	uint32_t module_id;
+	uint32_t module_vendor;
+	union {
+		struct {
+			uint8_t day;
+			uint8_t month;
+			uint16_t year;
+		};
+		uint32_t date;
+	};
+	uint32_t size_dw; /* uCode plus header_size_dw */
+	uint32_t key_size_dw;
+	uint32_t modulus_size_dw;
+	uint32_t exponent_size_dw;
+	union {
+		struct {
+			uint8_t hour;
+			uint8_t min;
+			uint16_t sec;
+		};
+		uint32_t time;
+	};
+
+	char username[8];
+	char buildnumber[12];
+	uint32_t device_id;
+	uint32_t guc_sw_version;
+	uint32_t prod_preprod_fw;
+	uint32_t reserved[12];
+	uint32_t header_info;
+} __packed;
+
 struct guc_doorbell_info {
 	u32 db_status;
 	u32 cookie;

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) {