ALSA: scarlett2: Retrieve useful flash segment numbers

Call SCARLETT2_USB_INFO_FLASH and SCARLETT2_USB_INFO_SEGMENT to find
the App_Settings and App_Upgrade flash segment numbers, and store them
in the scarlett2_data struct. These will be used later to implement
reset to factory defaults and firmware upgrade functions.
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/70f0108a9cf99b69f7aa920c4bcdb0cf4bf3da98.1703001053.git.g@b4.vuSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_scarlett2.c

@@ -190,6 +190,11 @@ static const u16 scarlett2_mixer_values[SCARLETT2_MIXER_VALUE_COUNT] = {
 	16345
 };
 
+/* Flash segments that we may manipulate */
+#define SCARLETT2_SEGMENT_ID_SETTINGS 0
+#define SCARLETT2_SEGMENT_ID_FIRMWARE 1
+#define SCARLETT2_SEGMENT_ID_COUNT 2
+
 /* Maximum number of analogue outputs */
 #define SCARLETT2_ANALOGUE_MAX 10
 
@@ -429,6 +434,8 @@ struct scarlett2_data {
 	int num_mux_srcs;
 	int num_mux_dsts;
 	u32 firmware_version;
+	u8 flash_segment_nums[SCARLETT2_SEGMENT_ID_COUNT];
+	u8 flash_segment_blocks[SCARLETT2_SEGMENT_ID_COUNT];
 	u16 scarlett2_seq;
 	u8 sync_updated;
 	u8 vol_updated;
@@ -1160,6 +1167,13 @@ static int scarlett2_get_port_start_num(
 #define SCARLETT2_USB_VOLUME_STATUS_OFFSET 0x31
 #define SCARLETT2_USB_METER_LEVELS_GET_MAGIC 1
 
+#define SCARLETT2_FLASH_BLOCK_SIZE 4096
+#define SCARLETT2_SEGMENT_NUM_MIN 1
+#define SCARLETT2_SEGMENT_NUM_MAX 4
+
+#define SCARLETT2_SEGMENT_SETTINGS_NAME "App_Settings"
+#define SCARLETT2_SEGMENT_FIRMWARE_NAME "App_Upgrade"
+
 /* volume status is read together (matches scarlett2_config_items[1]) */
 struct scarlett2_usb_volume_status {
 	/* dim/mute buttons */
@@ -4202,6 +4216,90 @@ static int scarlett2_usb_init(struct usb_mixer_interface *mixer)
 	return 0;
 }
 
+/* Get the flash segment numbers for the App_Settings and App_Upgrade
+ * segments and put them in the private data
+ */
+static int scarlett2_get_flash_segment_nums(struct usb_mixer_interface *mixer)
+{
+	struct scarlett2_data *private = mixer->private_data;
+	int err, count, i;
+
+	struct {
+		__le32 size;
+		__le32 count;
+		u8 unknown[8];
+	} __packed flash_info;
+
+	struct {
+		__le32 size;
+		__le32 flags;
+		char name[16];
+	} __packed segment_info;
+
+	err = scarlett2_usb(mixer, SCARLETT2_USB_INFO_FLASH,
+			    NULL, 0,
+			    &flash_info, sizeof(flash_info));
+	if (err < 0)
+		return err;
+
+	count = le32_to_cpu(flash_info.count);
+
+	/* sanity check count */
+	if (count < SCARLETT2_SEGMENT_NUM_MIN ||
+	    count > SCARLETT2_SEGMENT_NUM_MAX + 1) {
+		usb_audio_err(mixer->chip,
+			      "invalid flash segment count: %d\n", count);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < count; i++) {
+		__le32 segment_num_req = cpu_to_le32(i);
+		int flash_segment_id;
+
+		err = scarlett2_usb(mixer, SCARLETT2_USB_INFO_SEGMENT,
+				    &segment_num_req, sizeof(segment_num_req),
+				    &segment_info, sizeof(segment_info));
+		if (err < 0) {
+			usb_audio_err(mixer->chip,
+				"failed to get flash segment info %d: %d\n",
+				i, err);
+			return err;
+		}
+
+		if (!strncmp(segment_info.name,
+			     SCARLETT2_SEGMENT_SETTINGS_NAME, 16))
+			flash_segment_id = SCARLETT2_SEGMENT_ID_SETTINGS;
+		else if (!strncmp(segment_info.name,
+				  SCARLETT2_SEGMENT_FIRMWARE_NAME, 16))
+			flash_segment_id = SCARLETT2_SEGMENT_ID_FIRMWARE;
+		else
+			continue;
+
+		private->flash_segment_nums[flash_segment_id] = i;
+		private->flash_segment_blocks[flash_segment_id] =
+			le32_to_cpu(segment_info.size) /
+				SCARLETT2_FLASH_BLOCK_SIZE;
+	}
+
+	/* segment 0 is App_Gold and we never want to touch that, so
+	 * use 0 as the "not-found" value
+	 */
+	if (!private->flash_segment_nums[SCARLETT2_SEGMENT_ID_SETTINGS]) {
+		usb_audio_err(mixer->chip,
+			      "failed to find flash segment %s\n",
+			      SCARLETT2_SEGMENT_SETTINGS_NAME);
+		return -EINVAL;
+	}
+	if (!private->flash_segment_nums[SCARLETT2_SEGMENT_ID_FIRMWARE]) {
+		usb_audio_err(mixer->chip,
+			      "failed to find flash segment %s\n",
+			      SCARLETT2_SEGMENT_FIRMWARE_NAME);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /* Read configuration from the interface on start */
 static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
 {
@@ -4517,6 +4615,11 @@ static int snd_scarlett2_controls_create(
 	if (err < 0)
 		return err;
 
+	/* Get the upgrade & settings flash segment numbers */
+	err = scarlett2_get_flash_segment_nums(mixer);
+	if (err < 0)
+		return err;
+
 	/* Add firmware version control */
 	err = scarlett2_add_firmware_version_ctl(mixer);
 	if (err < 0)