ASoC: SOF: Introduce offset in firmware data

It makes possible to provide extra information to host
before downloading firmware. Extra data should be put
at the beginning of firmware binary.
Exchange is done without any effort on DSP side.
This mechanism will be used in extended manifest.
Signed-off-by: Karol Trzcinski <karolx.trzcinski@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200415202816.934-4-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/sound/sof.h

@@ -27,6 +27,9 @@ struct snd_sof_pdata {
 
 	struct device *dev;
 
+	/* indicate how many first bytes shouldn't be loaded into DSP memory. */
+	size_t fw_offset;
+
 	/*
 	 * notification callback used if the hardware initialization
 	 * can take time or is handled in a workqueue. This callback

sound/soc/sof/intel/hda-loader.c

@@ -293,8 +293,13 @@ int hda_dsp_cl_boot_firmware(struct snd_sof_dev *sdev)
 
 	chip_info = desc->chip_info;
 
-	stripped_firmware.data = plat_data->fw->data;
-	stripped_firmware.size = plat_data->fw->size;
+	if (plat_data->fw->size < plat_data->fw_offset) {
+		dev_err(sdev->dev, "error: firmware size must be greater than firmware offset\n");
+		return -EINVAL;
+	}
+
+	stripped_firmware.data = plat_data->fw->data + plat_data->fw_offset;
+	stripped_firmware.size = plat_data->fw->size - plat_data->fw_offset;
 
 	/* init for booting wait */
 	init_waitqueue_head(&sdev->boot_wait);

sound/soc/sof/loader.c

@@ -379,12 +379,19 @@ int snd_sof_parse_module_memcpy(struct snd_sof_dev *sdev,
 }
 EXPORT_SYMBOL(snd_sof_parse_module_memcpy);
 
-static int check_header(struct snd_sof_dev *sdev, const struct firmware *fw)
+static int check_header(struct snd_sof_dev *sdev, const struct firmware *fw,
+			size_t fw_offset)
 {
 	struct snd_sof_fw_header *header;
+	size_t fw_size = fw->size - fw_offset;
+
+	if (fw->size < fw_offset) {
+		dev_err(sdev->dev, "error: firmware size must be greater than firmware offset\n");
+		return -EINVAL;
+	}
 
 	/* Read the header information from the data pointer */
-	header = (struct snd_sof_fw_header *)fw->data;
+	header = (struct snd_sof_fw_header *)(fw->data + fw_offset);
 
 	/* verify FW sig */
 	if (strncmp(header->sig, SND_SOF_FW_SIG, SND_SOF_FW_SIG_SIZE) != 0) {
@@ -393,9 +400,9 @@ static int check_header(struct snd_sof_dev *sdev, const struct firmware *fw)
 	}
 
 	/* check size is valid */
-	if (fw->size != header->file_size + sizeof(*header)) {
+	if (fw_size != header->file_size + sizeof(*header)) {
 		dev_err(sdev->dev, "error: invalid filesize mismatch got 0x%zx expected 0x%zx\n",
-			fw->size, header->file_size + sizeof(*header));
+			fw_size, header->file_size + sizeof(*header));
 		return -EINVAL;
 	}
 
@@ -406,7 +413,8 @@ static int check_header(struct snd_sof_dev *sdev, const struct firmware *fw)
 	return 0;
 }
 
-static int load_modules(struct snd_sof_dev *sdev, const struct firmware *fw)
+static int load_modules(struct snd_sof_dev *sdev, const struct firmware *fw,
+			size_t fw_offset)
 {
 	struct snd_sof_fw_header *header;
 	struct snd_sof_mod_hdr *module;
@@ -415,14 +423,15 @@ static int load_modules(struct snd_sof_dev *sdev, const struct firmware *fw)
 	int ret, count;
 	size_t remaining;
 
-	header = (struct snd_sof_fw_header *)fw->data;
+	header = (struct snd_sof_fw_header *)(fw->data + fw_offset);
 	load_module = sof_ops(sdev)->load_module;
 	if (!load_module)
 		return -EINVAL;
 
 	/* parse each module */
-	module = (struct snd_sof_mod_hdr *)((u8 *)(fw->data) + sizeof(*header));
-	remaining = fw->size - sizeof(*header);
+	module = (struct snd_sof_mod_hdr *)(fw->data + fw_offset +
+					    sizeof(*header));
+	remaining = fw->size - sizeof(*header) - fw_offset;
 	/* check for wrap */
 	if (remaining > fw->size) {
 		dev_err(sdev->dev, "error: fw size smaller than header size\n");
@@ -502,7 +511,7 @@ int snd_sof_load_firmware_memcpy(struct snd_sof_dev *sdev)
 		return ret;
 
 	/* make sure the FW header and file is valid */
-	ret = check_header(sdev, plat_data->fw);
+	ret = check_header(sdev, plat_data->fw, plat_data->fw_offset);
 	if (ret < 0) {
 		dev_err(sdev->dev, "error: invalid FW header\n");
 		goto error;
@@ -516,7 +525,7 @@ int snd_sof_load_firmware_memcpy(struct snd_sof_dev *sdev)
 	}
 
 	/* parse and load firmware modules to DSP */
-	ret = load_modules(sdev, plat_data->fw);
+	ret = load_modules(sdev, plat_data->fw, plat_data->fw_offset);
 	if (ret < 0) {
 		dev_err(sdev->dev, "error: invalid FW modules\n");
 		goto error;