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Subject[PATCH v3 6/6] hid: add experimental access to PicoLCD device's EEPROM and FLASH
The PicoLCD device has a small amount of EEPROM and also provides access
to its FLASH where firmware and splash image are saved.
In flasher mode FLASH access is the only active feature.

Give read/write access to both via debugfs files.

NOTE: EEPROM and FLASH access should be switched to better suited API,
until then they will reside in debugfs

Changes since v2:
- Drop inline keyword on non-stub functions
- Prevent interleaved flash writes via mutex
- Add description of flash/eeprom access schematics

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
---
drivers/hid/Kconfig | 2 +-
drivers/hid/hid-picolcd.c | 439 +++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 423 insertions(+), 18 deletions(-)
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 34f6593..a2ecd83 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -281,9 +281,9 @@ config HID_PICOLCD
- Backlight control (needs CONFIG_BACKLIGHT_CLASS_DEVICE)
- Contrast control (needs CONFIG_LCD_CLASS_DEVICE)
- General purpose outputs (needs CONFIG_LEDS_CLASS)
+ - EEProm / Flash access (via debugfs)
Features that are not (yet) supported:
- IR
- - EEProm / Flash access

config HID_QUANTA
tristate "Quanta Optical Touch"
diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index ff70aa2..6a88a72 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -169,6 +169,10 @@ struct picolcd_pending {
struct picolcd_data {
struct hid_device *hdev;
#ifdef CONFIG_DEBUG_FS
+ struct dentry *debug_reset;
+ struct dentry *debug_eeprom;
+ struct dentry *debug_flash;
+ struct mutex mutex_flash;
int addr_sz;
#endif
u8 version[2];
@@ -1301,6 +1305,357 @@ static DEVICE_ATTR(operation_mode, 0644, picolcd_operation_mode_show,

#ifdef CONFIG_DEBUG_FS
/*
+ * The "reset" file
+ */
+static int picolcd_debug_reset_show(struct seq_file *f, void *p)
+{
+ if (picolcd_fbinfo((struct picolcd_data *)f->private))
+ seq_printf(f, "all fb\n");
+ else
+ seq_printf(f, "all\n");
+ return 0;
+}
+
+static ssize_t picolcd_debug_reset_open(struct inode *inode, struct file *f)
+{
+ return single_open(f, picolcd_debug_reset_show, inode->i_private);
+}
+
+static ssize_t picolcd_debug_reset_write(struct file *f, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct picolcd_data *data = ((struct seq_file *)f->private_data)->private;
+ char buf[32];
+ size_t cnt = min(count, sizeof(buf)-1);
+ if (copy_from_user(buf, user_buf, cnt))
+ return -EFAULT;
+
+ while (cnt > 0 && (buf[cnt-1] == ' ' || buf[cnt-1] == '\n'))
+ cnt--;
+ buf[cnt] = '\0';
+ if (strcmp(buf, "all") == 0) {
+ picolcd_reset(data->hdev);
+ picolcd_fb_reset(data, 1);
+ } else if (strcmp(buf, "fb") == 0) {
+ picolcd_fb_reset(data, 1);
+ } else {
+ return -EINVAL;
+ }
+ return count;
+}
+
+static const struct file_operations picolcd_debug_reset_fops = {
+ .owner = THIS_MODULE,
+ .open = picolcd_debug_reset_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .write = picolcd_debug_reset_write,
+ .release = single_release,
+};
+
+/*
+ * The "eeprom" file
+ */
+static int picolcd_debug_eeprom_open(struct inode *i, struct file *f)
+{
+ f->private_data = i->i_private;
+ return 0;
+}
+
+static ssize_t picolcd_debug_eeprom_read(struct file *f, char __user *u,
+ size_t s, loff_t *off)
+{
+ struct picolcd_data *data = f->private_data;
+ struct picolcd_pending *resp;
+ u8 raw_data[3];
+ ssize_t ret = -EIO;
+
+ if (s == 0)
+ return -EINVAL;
+ if (*off > 0x0ff)
+ return 0;
+
+ /* prepare buffer with info about what we want to read (addr & len) */
+ raw_data[0] = *off & 0xff;
+ raw_data[1] = (*off >> 8) && 0xff;
+ raw_data[2] = s < 20 ? s : 20;
+ if (*off + raw_data[2] > 0xff)
+ raw_data[2] = 0x100 - *off;
+ resp = picolcd_send_and_wait(data->hdev, REPORT_EE_READ, raw_data,
+ sizeof(raw_data));
+ if (!resp)
+ return -EIO;
+
+ if (resp->in_report && resp->in_report->id == REPORT_EE_DATA) {
+ /* successful read :) */
+ ret = resp->raw_data[2];
+ if (ret > s)
+ ret = s;
+ if (copy_to_user(u, resp->raw_data+3, ret))
+ ret = -EFAULT;
+ else
+ *off += ret;
+ } /* anything else is some kind of IO error */
+
+ kfree(resp);
+ return ret;
+}
+
+static ssize_t picolcd_debug_eeprom_write(struct file *f, const char __user *u,
+ size_t s, loff_t *off)
+{
+ struct picolcd_data *data = f->private_data;
+ struct picolcd_pending *resp;
+ ssize_t ret = -EIO;
+ u8 raw_data[23];
+
+ if (s == 0)
+ return -EINVAL;
+ if (*off > 0x0ff)
+ return -ENOSPC;
+
+ memset(raw_data, 0, sizeof(raw_data));
+ raw_data[0] = *off & 0xff;
+ raw_data[1] = (*off >> 8) && 0xff;
+ raw_data[2] = s < 20 ? s : 20;
+ if (*off + raw_data[2] > 0xff)
+ raw_data[2] = 0x100 - *off;
+
+ if (copy_from_user(raw_data+3, u, raw_data[2]))
+ return -EFAULT;
+ resp = picolcd_send_and_wait(data->hdev, REPORT_EE_WRITE, raw_data,
+ sizeof(raw_data));
+
+ if (!resp)
+ return -EIO;
+
+ if (resp->in_report && resp->in_report->id == REPORT_EE_DATA) {
+ /* check if written data matches */
+ if (memcmp(raw_data, resp->raw_data, 3+raw_data[2]) == 0) {
+ *off += raw_data[2];
+ ret = raw_data[2];
+ }
+ }
+ kfree(resp);
+ return ret;
+}
+
+/*
+ * Notes:
+ * - read/write happens in chunks of at most 20 bytes, it's up to userspace
+ * to loop in order to get more data.
+ * - on write errors on otherwise correct write request the bytes
+ * that should have been written are in undefined state.
+ */
+static const struct file_operations picolcd_debug_eeprom_fops = {
+ .owner = THIS_MODULE,
+ .open = picolcd_debug_eeprom_open,
+ .read = picolcd_debug_eeprom_read,
+ .write = picolcd_debug_eeprom_write,
+ .llseek = generic_file_llseek,
+};
+
+/*
+ * The "flash" file
+ */
+static int picolcd_debug_flash_open(struct inode *i, struct file *f)
+{
+ f->private_data = i->i_private;
+ return 0;
+}
+
+/* record a flash address to buf (bounds check to be done by caller) */
+static int _picolcd_flash_setaddr(struct picolcd_data *data, u8 *buf, long off)
+{
+ buf[0] = off & 0xff;
+ buf[1] = (off >> 8) & 0xff;
+ if (data->addr_sz == 3)
+ buf[2] = (off >> 16) & 0xff;
+ return data->addr_sz == 2 ? 2 : 3;
+}
+
+/* read a given size of data (bounds check to be done by caller) */
+static ssize_t _picolcd_flash_read(struct picolcd_data *data, int report_id,
+ char __user *u, size_t s, loff_t *off)
+{
+ struct picolcd_pending *resp;
+ u8 raw_data[4];
+ ssize_t ret = 0;
+ int len_off, err = -EIO;
+
+ while (s > 0) {
+ err = -EIO;
+ len_off = _picolcd_flash_setaddr(data, raw_data, *off);
+ raw_data[len_off] = s > 32 ? 32 : s;
+ resp = picolcd_send_and_wait(data->hdev, report_id, raw_data, len_off+1);
+ if (!resp || !resp->in_report)
+ goto skip;
+ if (resp->in_report->id == REPORT_MEMORY ||
+ resp->in_report->id == REPORT_BL_READ_MEMORY) {
+ if (memcmp(raw_data, resp->raw_data, len_off+1) != 0)
+ goto skip;
+ if (copy_to_user(u+ret, resp->raw_data+len_off+1, raw_data[len_off])) {
+ err = -EFAULT;
+ goto skip;
+ }
+ *off += raw_data[len_off];
+ s -= raw_data[len_off];
+ ret += raw_data[len_off];
+ err = 0;
+ }
+skip:
+ kfree(resp);
+ if (err)
+ return ret > 0 ? ret : err;
+ }
+ return ret;
+}
+
+static ssize_t picolcd_debug_flash_read(struct file *f, char __user *u,
+ size_t s, loff_t *off)
+{
+ struct picolcd_data *data = f->private_data;
+
+ if (s == 0)
+ return -EINVAL;
+ if (*off > 0x05fff)
+ return 0;
+ if (*off + s > 0x05fff)
+ s = 0x06000 - *off;
+
+ if (data->status & PICOLCD_BOOTLOADER)
+ return _picolcd_flash_read(data, REPORT_BL_READ_MEMORY, u, s, off);
+ else
+ return _picolcd_flash_read(data, REPORT_READ_MEMORY, u, s, off);
+}
+
+/* erase block aligned to 64bytes boundary */
+static ssize_t _picolcd_flash_erase64(struct picolcd_data *data, int report_id,
+ loff_t *off)
+{
+ struct picolcd_pending *resp;
+ u8 raw_data[3];
+ int len_off;
+ ssize_t ret = -EIO;
+
+ if (*off & 0x3f)
+ return -EINVAL;
+
+ len_off = _picolcd_flash_setaddr(data, raw_data, *off);
+ resp = picolcd_send_and_wait(data->hdev, report_id, raw_data, len_off);
+ if (!resp || !resp->in_report)
+ goto skip;
+ if (resp->in_report->id == REPORT_MEMORY ||
+ resp->in_report->id == REPORT_BL_ERASE_MEMORY) {
+ if (memcmp(raw_data, resp->raw_data, len_off) != 0)
+ goto skip;
+ ret = 0;
+ }
+skip:
+ kfree(resp);
+ return ret;
+}
+
+/* write a given size of data (bounds check to be done by caller) */
+static ssize_t _picolcd_flash_write(struct picolcd_data *data, int report_id,
+ const char __user *u, size_t s, loff_t *off)
+{
+ struct picolcd_pending *resp;
+ u8 raw_data[36];
+ ssize_t ret = 0;
+ int len_off, err = -EIO;
+
+ while (s > 0) {
+ err = -EIO;
+ len_off = _picolcd_flash_setaddr(data, raw_data, *off);
+ raw_data[len_off] = s > 32 ? 32 : s;
+ if (copy_from_user(raw_data+len_off+1, u, raw_data[len_off])) {
+ err = -EFAULT;
+ goto skip;
+ }
+ resp = picolcd_send_and_wait(data->hdev, report_id, raw_data,
+ len_off+1+raw_data[len_off]);
+ if (!resp || !resp->in_report)
+ goto skip;
+ if (resp->in_report->id == REPORT_MEMORY ||
+ resp->in_report->id == REPORT_BL_WRITE_MEMORY) {
+ if (memcmp(raw_data, resp->raw_data, len_off+1+raw_data[len_off]) != 0)
+ goto skip;
+ *off += raw_data[len_off];
+ s -= raw_data[len_off];
+ ret += raw_data[len_off];
+ err = 0;
+ }
+skip:
+ kfree(resp);
+ if (err)
+ break;
+ }
+ return ret > 0 ? ret : err;
+}
+
+static ssize_t picolcd_debug_flash_write(struct file *f, const char __user *u,
+ size_t s, loff_t *off)
+{
+ struct picolcd_data *data = f->private_data;
+ ssize_t err, ret = 0;
+ int report_erase, report_write;
+
+ if (s == 0)
+ return -EINVAL;
+ if (*off > 0x5fff)
+ return -ENOSPC;
+ if (s & 0x3f)
+ return -EINVAL;
+ if (*off & 0x3f)
+ return -EINVAL;
+
+ if (data->status & PICOLCD_BOOTLOADER) {
+ report_erase = REPORT_BL_ERASE_MEMORY;
+ report_write = REPORT_BL_WRITE_MEMORY;
+ } else {
+ report_erase = REPORT_ERASE_MEMORY;
+ report_write = REPORT_WRITE_MEMORY;
+ }
+ mutex_lock(&data->mutex_flash);
+ while (s > 0) {
+ err = _picolcd_flash_erase64(data, report_erase, off);
+ if (err)
+ break;
+ err = _picolcd_flash_write(data, report_write, u, 64, off);
+ if (err < 0)
+ break;
+ ret += err;
+ *off += err;
+ s -= err;
+ if (err != 64)
+ break;
+ }
+ mutex_unlock(&data->mutex_flash);
+ return ret > 0 ? ret : err;
+}
+
+/*
+ * Notes:
+ * - concurrent writing is prevented by mutex and all writes must be
+ * n*64 bytes and 64-byte aligned, each write being preceeded by an
+ * ERASE which erases a 64byte block.
+ * If less than requested was written or an error is returned for an
+ * otherwise correct write request the next 64-byte block which should
+ * have been written is in undefined state (mostly: original, erased,
+ * (half-)written with write error)
+ * - reading can happend without special restriction
+ */
+static const struct file_operations picolcd_debug_flash_fops = {
+ .owner = THIS_MODULE,
+ .open = picolcd_debug_flash_open,
+ .read = picolcd_debug_flash_read,
+ .write = picolcd_debug_flash_write,
+ .llseek = generic_file_llseek,
+};
+
+
+/*
* Helper code for HID report level dumping/debugging
*/
static const char *error_codes[] = {
@@ -1775,9 +2130,66 @@ static void picolcd_debug_raw_event(struct picolcd_data *data,
wake_up_interruptible(&hdev->debug_wait);
kfree(buff);
}
+
+static void picolcd_init_devfs(struct picolcd_data *data,
+ struct hid_report *eeprom_r, struct hid_report *eeprom_w,
+ struct hid_report *flash_r, struct hid_report *flash_w,
+ struct hid_report *reset)
+{
+ struct hid_device *hdev = data->hdev;
+
+ mutex_init(&data->mutex_flash);
+
+ /* reset */
+ if (reset)
+ data->debug_reset = debugfs_create_file("reset", 0600,
+ hdev->debug_dir, data, &picolcd_debug_reset_fops);
+
+ /* eeprom */
+ if (eeprom_r || eeprom_w)
+ data->debug_eeprom = debugfs_create_file("eeprom",
+ (eeprom_w ? S_IWUSR : 0) | (eeprom_r ? S_IRUSR : 0),
+ hdev->debug_dir, data, &picolcd_debug_eeprom_fops);
+
+ /* flash */
+ if (flash_r && flash_r->maxfield == 1 && flash_r->field[0]->report_size == 8)
+ data->addr_sz = flash_r->field[0]->report_count - 1;
+ else
+ data->addr_sz = -1;
+ if (data->addr_sz == 2 || data->addr_sz == 3) {
+ data->debug_flash = debugfs_create_file("flash",
+ (flash_w ? S_IWUSR : 0) | (flash_r ? S_IRUSR : 0),
+ hdev->debug_dir, data, &picolcd_debug_flash_fops);
+ } else if (flash_r || flash_w)
+ dev_warn(&hdev->dev, "Unexpected FLASH access reports, "
+ "please submit rdesc for review\n");
+}
+
+static void picolcd_exit_devfs(struct picolcd_data *data)
+{
+ struct dentry *dent;
+
+ dent = data->debug_reset;
+ data->debug_reset = NULL;
+ if (dent)
+ debugfs_remove(dent);
+ dent = data->debug_eeprom;
+ data->debug_eeprom = NULL;
+ if (dent)
+ debugfs_remove(dent);
+ dent = data->debug_flash;
+ data->debug_flash = NULL;
+ if (dent)
+ debugfs_remove(dent);
+ mutex_destroy(&data->mutex_flash);
+}
#else
#define picolcd_debug_raw_event(data, hdev, report, raw_data, size)
-#endif
+#define picolcd_init_devfs(data, eeprom_r, eeprom_w, flash_r, flash_w, reset)
+static void picolcd_exit_devfs(struct picolcd_data *data)
+{
+}
+#endif /* CONFIG_DEBUG_FS */

/*
* Handle raw report as sent by device
@@ -1927,7 +2339,6 @@ static inline void picolcd_exit_cir(struct picolcd_data *data)

static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
{
- struct hid_report *report;
int error;

error = picolcd_check_version(hdev);
@@ -1969,13 +2380,11 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
if (error)
goto err;

-#ifdef CONFIG_DEBUG_FS
- report = picolcd_out_report(REPORT_READ_MEMORY, hdev);
- if (report && report->maxfield == 1 && report->field[0]->report_size == 8)
- data->addr_sz = report->field[0]->report_count - 1;
- else
- data->addr_sz = -1;
-#endif
+ picolcd_init_devfs(data, picolcd_out_report(REPORT_EE_READ, hdev),
+ picolcd_out_report(REPORT_EE_WRITE, hdev),
+ picolcd_out_report(REPORT_READ_MEMORY, hdev),
+ picolcd_out_report(REPORT_WRITE_MEMORY, hdev),
+ picolcd_out_report(REPORT_RESET, hdev));
return 0;
err:
picolcd_exit_leds(data);
@@ -1989,7 +2398,6 @@ err:

static int picolcd_probe_bootloader(struct hid_device *hdev, struct picolcd_data *data)
{
- struct hid_report *report;
int error;

error = picolcd_check_version(hdev);
@@ -2001,13 +2409,9 @@ static int picolcd_probe_bootloader(struct hid_device *hdev, struct picolcd_data
"please submit /sys/kernel/debug/hid/%s/rdesc for this device.\n",
dev_name(&hdev->dev));

-#ifdef CONFIG_DEBUG_FS
- report = picolcd_out_report(REPORT_BL_READ_MEMORY, hdev);
- if (report && report->maxfield == 1 && report->field[0]->report_size == 8)
- data->addr_sz = report->field[0]->report_count - 1;
- else
- data->addr_sz = -1;
-#endif
+ picolcd_init_devfs(data, NULL, NULL,
+ picolcd_out_report(REPORT_BL_READ_MEMORY, hdev),
+ picolcd_out_report(REPORT_BL_WRITE_MEMORY, hdev), NULL);
return 0;
}

@@ -2100,6 +2504,7 @@ static void picolcd_remove(struct hid_device *hdev)
data->status |= PICOLCD_FAILED;
spin_unlock_irqrestore(&data->lock, flags);

+ picolcd_exit_devfs(data);
device_remove_file(&hdev->dev, &dev_attr_operation_mode);
hdev->ll_driver->close(hdev);
hid_hw_stop(hdev);
--
1.6.4.4
--
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