diff options
| -rw-r--r-- | drivers/fsi/fsi-occ.c | 54 |
1 files changed, 37 insertions, 17 deletions
diff --git a/drivers/fsi/fsi-occ.c b/drivers/fsi/fsi-occ.c index b223f0ef337b..ecf738411fe2 100644 --- a/drivers/fsi/fsi-occ.c +++ b/drivers/fsi/fsi-occ.c @@ -50,6 +50,7 @@ struct occ { struct device *sbefifo; char name[32]; int idx; + u8 sequence_number; enum versions version; struct miscdevice mdev; struct mutex occ_lock; @@ -141,8 +142,7 @@ static ssize_t occ_write(struct file *file, const char __user *buf, { struct occ_client *client = file->private_data; size_t rlen, data_length; - u16 checksum = 0; - ssize_t rc, i; + ssize_t rc; u8 *cmd; if (!client) @@ -156,9 +156,6 @@ static ssize_t occ_write(struct file *file, const char __user *buf, /* Construct the command */ cmd = client->buffer; - /* Sequence number (we could increment and compare with response) */ - cmd[0] = 1; - /* * Copy the user command (assume user data follows the occ command * format) @@ -178,14 +175,7 @@ static ssize_t occ_write(struct file *file, const char __user *buf, goto done; } - /* Calculate checksum */ - for (i = 0; i < data_length + 4; ++i) - checksum += cmd[i]; - - cmd[data_length + 4] = checksum >> 8; - cmd[data_length + 5] = checksum & 0xFF; - - /* Submit command */ + /* Submit command; 4 bytes before the data and 2 bytes after */ rlen = PAGE_SIZE; rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd, &rlen); @@ -314,11 +304,13 @@ free: return rc; } -static int occ_putsram(struct occ *occ, const void *data, ssize_t len) +static int occ_putsram(struct occ *occ, const void *data, ssize_t len, + u8 seq_no, u16 checksum) { size_t cmd_len, buf_len, resp_len, resp_data_len; u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */ __be32 *buf; + u8 *byte_buf; int idx = 0, rc; cmd_len = (occ->version == occ_p10) ? 6 : 5; @@ -358,6 +350,15 @@ static int occ_putsram(struct occ *occ, const void *data, ssize_t len) buf[4 + idx] = cpu_to_be32(data_len); memcpy(&buf[5 + idx], data, len); + byte_buf = (u8 *)&buf[5 + idx]; + /* + * Overwrite the first byte with our sequence number and the last two + * bytes with the checksum. + */ + byte_buf[0] = seq_no; + byte_buf[len - 2] = checksum >> 8; + byte_buf[len - 1] = checksum & 0xff; + rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len); if (rc) goto free; @@ -467,9 +468,12 @@ int fsi_occ_submit(struct device *dev, const void *request, size_t req_len, struct occ *occ = dev_get_drvdata(dev); struct occ_response *resp = response; u8 seq_no; + u16 checksum = 0; u16 resp_data_length; + const u8 *byte_request = (const u8 *)request; unsigned long start; int rc; + size_t i; if (!occ) return -ENODEV; @@ -479,11 +483,26 @@ int fsi_occ_submit(struct device *dev, const void *request, size_t req_len, return -EINVAL; } + /* Checksum the request, ignoring first byte (sequence number). */ + for (i = 1; i < req_len - 2; ++i) + checksum += byte_request[i]; + mutex_lock(&occ->occ_lock); - /* Extract the seq_no from the command (first byte) */ - seq_no = *(const u8 *)request; - rc = occ_putsram(occ, request, req_len); + /* + * Get a sequence number and update the counter. Avoid a sequence + * number of 0 which would pass the response check below even if the + * OCC response is uninitialized. Any sequence number the user is + * trying to send is overwritten since this function is the only common + * interface to the OCC and therefore the only place we can guarantee + * unique sequence numbers. + */ + seq_no = occ->sequence_number++; + if (!occ->sequence_number) + occ->sequence_number = 1; + checksum += seq_no; + + rc = occ_putsram(occ, request, req_len, seq_no, checksum); if (rc) goto done; @@ -574,6 +593,7 @@ static int occ_probe(struct platform_device *pdev) occ->version = (uintptr_t)of_device_get_match_data(dev); occ->dev = dev; occ->sbefifo = dev->parent; + occ->sequence_number = 1; mutex_init(&occ->occ_lock); if (dev->of_node) { |