[PATCH] drm/panthor: Display FW version information

[Steven Price]

The firmware binary has a git SHA embedded into it which can be used to
identify which firmware binary is being loaded. Output this as a
drm_info() so that it's obvious from a dmesg log which firmware binary
is being used.

Signed-off-by: Steven Price <steven.price at arm.com>
---
 drivers/gpu/drm/panthor/panthor_fw.c | 55 ++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index 857f3f11258a..ef007287575c 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -78,6 +78,12 @@ enum panthor_fw_binary_entry_type {
 
 	/** @CSF_FW_BINARY_ENTRY_TYPE_TIMELINE_METADATA: Timeline metadata interface. */
 	CSF_FW_BINARY_ENTRY_TYPE_TIMELINE_METADATA = 4,
+
+	/**
+	 * @CSF_FW_BINARY_ENTRY_TYPE_BUILD_INFO_METADATA: Metadata about how
+	 * the FW binary was built.
+	 */
+	CSF_FW_BINARY_ENTRY_TYPE_BUILD_INFO_METADATA = 6
 };
 
 #define CSF_FW_BINARY_ENTRY_TYPE(ehdr)					((ehdr) & 0xff)
@@ -132,6 +138,13 @@ struct panthor_fw_binary_section_entry_hdr {
 	} data;
 };
 
+struct panthor_fw_build_info_hdr {
+	/** @meta_start: Offset of the build info data in the FW binary */
+	u32 meta_start;
+	/** @meta_size: Size of the build info data in the FW binary */
+	u32 meta_size;
+};
+
 /**
  * struct panthor_fw_binary_iter - Firmware binary iterator
  *
@@ -628,6 +641,46 @@ static int panthor_fw_load_section_entry(struct panthor_device *ptdev,
 	return 0;
 }
 
+static int panthor_fw_read_build_info(struct panthor_device *ptdev,
+				      const struct firmware *fw,
+				      struct panthor_fw_binary_iter *iter,
+				      u32 ehdr)
+{
+	struct panthor_fw_build_info_hdr hdr;
+	char header[9];
+	const char git_sha_header[sizeof(header)] = "git_sha: ";
+	int ret;
+
+	ret = panthor_fw_binary_iter_read(ptdev, iter, &hdr, sizeof(hdr));
+	if (ret)
+		return ret;
+
+	if (hdr.meta_start > fw->size ||
+	    hdr.meta_start + hdr.meta_size > fw->size) {
+		drm_err(&ptdev->base, "Firmware build info corrupt\n");
+		/* We don't need the build info, so continue */
+		return 0;
+	}
+
+	if (memcmp(git_sha_header, fw->data + hdr.meta_start,
+	    sizeof(git_sha_header))) {
+		/* Not the expected header, this isn't metadata we understand */
+		return 0;
+	}
+
+	/* Check that the git SHA is NULL terminated as expected */
+	if (fw->data[hdr.meta_start + hdr.meta_size - 1] != '\0') {
+		drm_warn(&ptdev->base, "Firmware's git sha is not NULL terminated\n");
+		/* Don't treat as fatal */
+		return 0;
+	}
+
+	drm_info(&ptdev->base, "Firmware git sha: %s\n",
+		 fw->data + hdr.meta_start + sizeof(git_sha_header));
+
+	return 0;
+}
+
 static void
 panthor_reload_fw_sections(struct panthor_device *ptdev, bool full_reload)
 {
@@ -672,6 +725,8 @@ static int panthor_fw_load_entry(struct panthor_device *ptdev,
 	switch (CSF_FW_BINARY_ENTRY_TYPE(ehdr)) {
 	case CSF_FW_BINARY_ENTRY_TYPE_IFACE:
 		return panthor_fw_load_section_entry(ptdev, fw, &eiter, ehdr);
+	case CSF_FW_BINARY_ENTRY_TYPE_BUILD_INFO_METADATA:
+		return panthor_fw_read_build_info(ptdev, fw, &eiter, ehdr);
 
 	/* FIXME: handle those entry types? */
 	case CSF_FW_BINARY_ENTRY_TYPE_CONFIG:
-- 
2.39.2