[PATCH] firmware_loader: Add debug message with checksum for FW file

[Amadeusz Sławiński]

Enable dynamic-debug logging of firmware filenames and SHA256 checksums
to clearly identify the firmware files that are loaded by the system.

Example output:
[   34.944619] firmware_class:_request_firmware: i915 0000:00:02.0: Loaded FW: i915/kbl_dmc_ver1_04.bin, sha256: 2cde41c3e5ad181423bcc3e98ff9c49f743c88f18646af4d0b3c3a9664b831a1
[   48.155884] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/cnl/dsp_basefw.bin, sha256: 43f6ac1b066e9bd0423d914960fbbdccb391af27d2b1da1085eee3ea8df0f357
[   49.579540] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/rt274-tplg.bin, sha256: 4b3580da96dc3d2c443ba20c6728d8b665fceb3ed57223c3a57582bbad8e2413
[   49.798196] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/hda-8086280c-tplg.bin, sha256: 5653172579b2be1b51fd69f5cf46e2bac8d63f2a1327924311c13b2f1fe6e601
[   49.859627] firmware_class:_request_firmware: snd_soc_avs 0000:00:1f.3: Loaded FW: intel/avs/dmic-tplg.bin, sha256: 00fb7fbdb74683333400d7e46925dae60db448b88638efcca0b30215db9df63f

Reviewed-by: Russ Weight <russell.h.weight@xxxxxxxxx>
Reviewed-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@xxxxxxxxxxxxxxx>
---
 drivers/base/firmware_loader/main.c | 45 ++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 017c4cdb219e..a6e1fb10763d 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -791,6 +791,47 @@ static void fw_abort_batch_reqs(struct firmware *fw)
 	mutex_unlock(&fw_lock);
 }
 
+#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
+#include <crypto/hash.h>
+#include <crypto/sha2.h>
+#define SHA256_STRING_SIZE (SHA256_DIGEST_SIZE * 2)
+static void fw_log_firmware_info(const struct firmware *fw, const char *name, struct device *device)
+{
+	char outbuf[SHA256_STRING_SIZE + 1];
+	u8 sha256buf[SHA256_DIGEST_SIZE];
+	struct shash_desc *shash;
+	struct crypto_shash *alg;
+
+	alg = crypto_alloc_shash("sha256", 0, 0);
+	if (!alg)
+		return;
+
+	shash = kmalloc(sizeof(*shash) + crypto_shash_descsize(alg), GFP_KERNEL);
+	if (!shash)
+		goto out_alg;
+
+	shash->tfm = alg;
+
+	if (crypto_shash_digest(shash, fw->data, fw->size, sha256buf) < 0)
+		goto out_shash;
+
+	for (int i = 0; i < SHA256_DIGEST_SIZE; i++)
+		sprintf(&outbuf[i * 2], "%02x", sha256buf[i]);
+	outbuf[SHA256_STRING_SIZE] = 0;
+	dev_dbg(device, "Loaded FW: %s, sha256: %s\n", name, outbuf);
+
+out_shash:
+	kfree(shash);
+out_alg:
+	crypto_free_shash(alg);
+
+}
+#else
+static void fw_log_firmware_info(const struct firmware *fw, const char *name,
+				 struct device *device)
+{}
+#endif
+
 /* called from request_firmware() and request_firmware_work_func() */
 static int
 _request_firmware(const struct firmware **firmware_p, const char *name,
@@ -861,11 +902,13 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
 	revert_creds(old_cred);
 	put_cred(kern_cred);
 
- out:
+out:
 	if (ret < 0) {
 		fw_abort_batch_reqs(fw);
 		release_firmware(fw);
 		fw = NULL;
+	} else {
+		fw_log_firmware_info(fw, name, device);
 	}
 
 	*firmware_p = fw;
-- 
2.34.1