drm/i915/dmc: extract fw_info and table walk from intel_package_header
Move fw_info out of struct intel_package_header to allow it to grow more
easily in future. To make a cleaner move, let's also extract a function to
search the header for the dmc_offset.
While reviewing this code I wondered why we continued the search even
after finding a suitable firmware. Add a comment to explain we will
continue to try to find a more specific firmware version, even if this
is not required by the spec.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190607091230.1489-3-lucas.demarchi@intel.com
diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
index 307ca79..3c1642e 100644
--- a/drivers/gpu/drm/i915/intel_csr.c
+++ b/drivers/gpu/drm/i915/intel_csr.c
@@ -70,6 +70,7 @@
MODULE_FIRMWARE(BXT_CSR_PATH);
#define CSR_DEFAULT_FW_OFFSET 0xFFFFFFFF
+#define PACKAGE_MAX_FW_INFO_ENTRIES 20
struct intel_css_header {
/* 0x09 for DMC */
@@ -139,8 +140,6 @@
/* Number of valid entries in the FWInfo array below */
u32 num_entries;
-
- struct intel_fw_info fw_info[20];
} __packed;
struct intel_dmc_header {
@@ -292,6 +291,46 @@
gen9_set_dc_state_debugmask(dev_priv);
}
+/*
+ * Search fw_info table for dmc_offset to find firmware binary: num_entries is
+ * already sanitized.
+ */
+static u32 find_dmc_fw_offset(const struct intel_fw_info *fw_info,
+ unsigned int num_entries,
+ const struct stepping_info *si)
+{
+ u32 dmc_offset = CSR_DEFAULT_FW_OFFSET;
+ unsigned int i;
+
+ for (i = 0; i < num_entries; i++) {
+ if (fw_info[i].substepping == '*' &&
+ si->stepping == fw_info[i].stepping) {
+ dmc_offset = fw_info[i].offset;
+ break;
+ }
+
+ if (si->stepping == fw_info[i].stepping &&
+ si->substepping == fw_info[i].substepping) {
+ dmc_offset = fw_info[i].offset;
+ break;
+ }
+
+ if (fw_info[i].stepping == '*' &&
+ fw_info[i].substepping == '*') {
+ /*
+ * In theory we should stop the search as generic
+ * entries should always come after the more specific
+ * ones, but let's continue to make sure to work even
+ * with "broken" firmwares. If we don't find a more
+ * specific one, then we use this entry
+ */
+ dmc_offset = fw_info[i].offset;
+ }
+ }
+
+ return dmc_offset;
+}
+
static u32 *parse_csr_fw(struct drm_i915_private *dev_priv,
const struct firmware *fw)
{
@@ -300,7 +339,7 @@
struct intel_dmc_header *dmc_header;
struct intel_csr *csr = &dev_priv->csr;
const struct stepping_info *si = intel_get_stepping_info(dev_priv);
- u32 dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
+ u32 dmc_offset, num_entries, readcount = 0, nbytes;
u32 i;
u32 *dmc_payload;
size_t fsize;
@@ -349,27 +388,26 @@
(package_header->header_len * 4));
return NULL;
}
- readcount += sizeof(struct intel_package_header);
- /* Search for dmc_offset to find firware binary. */
- for (i = 0; i < package_header->num_entries; i++) {
- if (package_header->fw_info[i].substepping == '*' &&
- si->stepping == package_header->fw_info[i].stepping) {
- dmc_offset = package_header->fw_info[i].offset;
- break;
- } else if (si->stepping == package_header->fw_info[i].stepping &&
- si->substepping == package_header->fw_info[i].substepping) {
- dmc_offset = package_header->fw_info[i].offset;
- break;
- } else if (package_header->fw_info[i].stepping == '*' &&
- package_header->fw_info[i].substepping == '*')
- dmc_offset = package_header->fw_info[i].offset;
- }
+ readcount += sizeof(struct intel_package_header);
+ num_entries = package_header->num_entries;
+ if (WARN_ON(package_header->num_entries > PACKAGE_MAX_FW_INFO_ENTRIES))
+ num_entries = PACKAGE_MAX_FW_INFO_ENTRIES;
+
+ fsize += PACKAGE_MAX_FW_INFO_ENTRIES * sizeof(struct intel_fw_info);
+ if (fsize > fw->size)
+ goto error_truncated;
+
+ dmc_offset = find_dmc_fw_offset((struct intel_fw_info *)
+ &fw->data[readcount], num_entries, si);
if (dmc_offset == CSR_DEFAULT_FW_OFFSET) {
DRM_ERROR("DMC firmware not supported for %c stepping\n",
si->stepping);
return NULL;
}
+ /* we always have space for PACKAGE_MAX_FW_INFO_ENTRIES */
+ readcount += PACKAGE_MAX_FW_INFO_ENTRIES * sizeof(struct intel_fw_info);
+
/* Convert dmc_offset into number of bytes. By default it is in dwords*/
dmc_offset *= 4;
readcount += dmc_offset;
