diff options
| -rw-r--r-- | drivers/scsi/scsi.c | 104 | ||||
| -rw-r--r-- | include/scsi/scsi_device.h | 1 |
2 files changed, 105 insertions, 0 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index cbcd3f681b62..a2ef03243a2c 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -967,6 +967,110 @@ int scsi_track_queue_full(struct scsi_device *sdev, int depth) EXPORT_SYMBOL(scsi_track_queue_full); /** + * scsi_vpd_inquiry - Request a device provide us with a VPD page + * @sdev: The device to ask + * @buffer: Where to put the result + * @page: Which Vital Product Data to return + * @len: The length of the buffer + * + * This is an internal helper function. You probably want to use + * scsi_get_vpd_page instead. + * + * Returns 0 on success or a negative error number. + */ +static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, + u8 page, unsigned len) +{ + int result; + unsigned char cmd[16]; + + cmd[0] = INQUIRY; + cmd[1] = 1; /* EVPD */ + cmd[2] = page; + cmd[3] = len >> 8; + cmd[4] = len & 0xff; + cmd[5] = 0; /* Control byte */ + + /* + * I'm not convinced we need to try quite this hard to get VPD, but + * all the existing users tried this hard. + */ + result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, + len + 4, NULL, 30 * HZ, 3, NULL); + if (result) + return result; + + /* Sanity check that we got the page back that we asked for */ + if (buffer[1] != page) + return -EIO; + + return 0; +} + +/** + * scsi_get_vpd_page - Get Vital Product Data from a SCSI device + * @sdev: The device to ask + * @page: Which Vital Product Data to return + * + * SCSI devices may optionally supply Vital Product Data. Each 'page' + * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). + * If the device supports this VPD page, this routine returns a pointer + * to a buffer containing the data from that page. The caller is + * responsible for calling kfree() on this pointer when it is no longer + * needed. If we cannot retrieve the VPD page this routine returns %NULL. + */ +unsigned char *scsi_get_vpd_page(struct scsi_device *sdev, u8 page) +{ + int i, result; + unsigned int len; + unsigned char *buf = kmalloc(259, GFP_KERNEL); + + if (!buf) + return NULL; + + /* Ask for all the pages supported by this device */ + result = scsi_vpd_inquiry(sdev, buf, 0, 255); + if (result) + goto fail; + + /* If the user actually wanted this page, we can skip the rest */ + if (page == 0) + return buf; + + for (i = 0; i < buf[3]; i++) + if (buf[i + 4] == page) + goto found; + /* The device claims it doesn't support the requested page */ + goto fail; + + found: + result = scsi_vpd_inquiry(sdev, buf, page, 255); + if (result) + goto fail; + + /* + * Some pages are longer than 255 bytes. The actual length of + * the page is returned in the header. + */ + len = (buf[2] << 8) | buf[3]; + if (len <= 255) + return buf; + + kfree(buf); + buf = kmalloc(len + 4, GFP_KERNEL); + result = scsi_vpd_inquiry(sdev, buf, page, len); + if (result) + goto fail; + + return buf; + + fail: + kfree(buf); + return NULL; +} +EXPORT_SYMBOL_GPL(scsi_get_vpd_page); + +/** * scsi_device_get - get an additional reference to a scsi_device * @sdev: device to get a reference to * diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 01a4c58f8bad..9576690901dd 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -340,6 +340,7 @@ extern int scsi_mode_select(struct scsi_device *sdev, int pf, int sp, struct scsi_sense_hdr *); extern int scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, struct scsi_sense_hdr *sshdr); +extern unsigned char *scsi_get_vpd_page(struct scsi_device *, u8 page); extern int scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state); extern struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, |