ALSA: scarlett2: Add support for reading from flash

Add hwdep read op so flash segments can be read.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Message-ID: <800d20a801e8c59c2905c82ecae5676cd4f31429.1710264833.git.g@b4.vu>

diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
index 02c488c80b7ec783355c5183c4e3447189876076..981ec48a811a81becc3e880be8ada79ca2bbde43 100644 (file)
--- a/sound/usb/mixer_scarlett2.c
+++ b/sound/usb/mixer_scarlett2.c
@@ -1859,6 +1859,7 @@ static int scarlett2_get_port_start_num(
 #define SCARLETT2_USB_ERASE_SEGMENT 0x00004002
 #define SCARLETT2_USB_GET_ERASE     0x00004003
 #define SCARLETT2_USB_WRITE_SEGMENT 0x00004004
+#define SCARLETT2_USB_READ_SEGMENT  0x00004005
 #define SCARLETT2_USB_GET_SYNC      0x00006004
 #define SCARLETT2_USB_GET_DATA      0x00800000
 #define SCARLETT2_USB_SET_DATA      0x00800001
@@ -1869,7 +1870,7 @@ static int scarlett2_get_port_start_num(
 #define SCARLETT2_USB_METER_LEVELS_GET_MAGIC 1
 
 #define SCARLETT2_FLASH_BLOCK_SIZE 4096
-#define SCARLETT2_FLASH_WRITE_MAX 1024
+#define SCARLETT2_FLASH_RW_MAX 1024
 #define SCARLETT2_SEGMENT_NUM_MIN 1
 #define SCARLETT2_SEGMENT_NUM_MAX 4
 
@@ -7452,7 +7453,7 @@ static int scarlett2_reboot(struct usb_mixer_interface *mixer)
        return scarlett2_usb(mixer, SCARLETT2_USB_REBOOT, NULL, 0, NULL, 0);
 }
 
-/* Select a flash segment for erasing (and possibly writing to) */
+/* Select a flash segment for reading/erasing/writing */
 static int scarlett2_ioctl_select_flash_segment(
        struct usb_mixer_interface *mixer,
        unsigned long arg)
@@ -7633,6 +7634,84 @@ static int scarlett2_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
        }
 }
 
+static long scarlett2_hwdep_read(struct snd_hwdep *hw,
+                                char __user *buf,
+                                long count, loff_t *offset)
+{
+       struct usb_mixer_interface *mixer = hw->private_data;
+       struct scarlett2_data *private = mixer->private_data;
+       int segment_id, segment_num, err;
+       int flash_size;
+
+       /* SCARLETT2_USB_READ_SEGMENT request data */
+       struct {
+               __le32 segment_num;
+               __le32 offset;
+               __le32 len;
+       } __packed req;
+
+       u8 *resp;
+
+       /* Flash segment must first be selected */
+       if (private->flash_write_state != SCARLETT2_FLASH_WRITE_STATE_SELECTED)
+               return -EINVAL;
+
+       /* Get the selected flash segment number */
+       segment_id = private->selected_flash_segment_id;
+       if (segment_id < 0 || segment_id >= SCARLETT2_SEGMENT_ID_COUNT)
+               return -EINVAL;
+
+       segment_num = private->flash_segment_nums[segment_id];
+       if (segment_num < 0 ||
+           segment_num > SCARLETT2_SEGMENT_NUM_MAX)
+               return -EFAULT;
+
+       /* Validate the offset and count */
+       if (count < 0 || *offset < 0)
+               return -EINVAL;
+
+       /* Reached EOF? */
+       flash_size = private->flash_segment_blocks[segment_id] *
+                    SCARLETT2_FLASH_BLOCK_SIZE;
+       if (!count || *offset >= flash_size)
+               return 0;
+
+       /* Limit the numbers of bytes read to SCARLETT2_FLASH_RW_MAX */
+       if (count > SCARLETT2_FLASH_RW_MAX)
+               count = SCARLETT2_FLASH_RW_MAX;
+
+       /* Limit read to EOF */
+       if (*offset + count >= flash_size)
+               count = flash_size - *offset;
+
+       /* Create and send the request */
+       req.segment_num = cpu_to_le32(segment_num);
+       req.offset = cpu_to_le32(*offset);
+       req.len = cpu_to_le32(count);
+
+       resp = kzalloc(count, GFP_KERNEL);
+       if (!resp)
+               return -ENOMEM;
+
+       err = scarlett2_usb(mixer, SCARLETT2_USB_READ_SEGMENT,
+                           &req, sizeof(req), resp, count);
+       if (err < 0)
+               goto error;
+
+       /* Copy the response to userspace */
+       if (copy_to_user(buf, resp, count)) {
+               err = -EFAULT;
+               goto error;
+       }
+
+       *offset += count;
+       err = count;
+
+error:
+       kfree(resp);
+       return err;
+}
+
 static long scarlett2_hwdep_write(struct snd_hwdep *hw,
                                  const char __user *buf,
                                  long count, loff_t *offset)
@@ -7651,7 +7730,7 @@ static long scarlett2_hwdep_write(struct snd_hwdep *hw,
        } __packed *req;
 
        /* Calculate the maximum permitted in data[] */
-       const size_t max_data_size = SCARLETT2_FLASH_WRITE_MAX -
+       const size_t max_data_size = SCARLETT2_FLASH_RW_MAX -
                                     offsetof(typeof(*req), data);
 
        /* If erasing, wait for it to complete */
@@ -7688,7 +7767,7 @@ static long scarlett2_hwdep_write(struct snd_hwdep *hw,
        if (!count)
                return 0;
 
-       /* Limit the *req size to SCARLETT2_FLASH_WRITE_MAX */
+       /* Limit the *req size to SCARLETT2_FLASH_RW_MAX */
        if (count > max_data_size)
                count = max_data_size;
 
@@ -7749,6 +7828,7 @@ static int scarlett2_hwdep_init(struct usb_mixer_interface *mixer)
        hw->exclusive = 1;
        hw->ops.open = scarlett2_hwdep_open;
        hw->ops.ioctl = scarlett2_hwdep_ioctl;
+       hw->ops.read = scarlett2_hwdep_read;
        hw->ops.write = scarlett2_hwdep_write;
        hw->ops.release = scarlett2_hwdep_release;