scsi: ufs: add support to read device and string descriptors

This change adds support to read device descriptor and string descriptor
from a UFS device

Reviewed-by: Gilad Broner <gbroner@codeaurora.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Raviv Shvili <rshvili@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 95 insertions, 1 deletions

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 54a16cef0367..aacb23521ef0 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -43,6 +43,7 @@
 #define GENERAL_UPIU_REQUEST_SIZE 32
 #define QUERY_DESC_MAX_SIZE       255
 #define QUERY_DESC_MIN_SIZE       2
+#define QUERY_DESC_HDR_SIZE       2
 #define QUERY_OSF_SIZE            (GENERAL_UPIU_REQUEST_SIZE - \
                                         (sizeof(struct utp_upiu_header)))
 
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 80031e6a63f5..e2ed41587f56 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -39,7 +39,7 @@
 
 #include <linux/async.h>
 #include <linux/devfreq.h>
-
+#include <linux/nls.h>
 #include <linux/of.h>
 #include "ufshcd.h"
 #include "unipro.h"
@@ -232,6 +232,16 @@ static inline void ufshcd_disable_irq(struct ufs_hba *hba)
         }
 }
 
+/* replace non-printable or non-ASCII characters with spaces */
+static inline void ufshcd_remove_non_printable(char *val)
+{
+        if (!val)
+                return;
+
+        if (*val < 0x20 || *val > 0x7e)
+                *val = ' ';
+}
+
 /*
  * ufshcd_wait_for_register - wait for register value to change
  * @hba - per-adapter interface
@@ -2021,6 +2031,82 @@ static inline int ufshcd_read_power_desc(struct ufs_hba *hba,
         return ufshcd_read_desc(hba, QUERY_DESC_IDN_POWER, 0, buf, size);
 }
 
+int ufshcd_read_device_desc(struct ufs_hba *hba, u8 *buf, u32 size)
+{
+        return ufshcd_read_desc(hba, QUERY_DESC_IDN_DEVICE, 0, buf, size);
+}
+EXPORT_SYMBOL(ufshcd_read_device_desc);
+
+/**
+ * ufshcd_read_string_desc - read string descriptor
+ * @hba: pointer to adapter instance
+ * @desc_index: descriptor index
+ * @buf: pointer to buffer where descriptor would be read
+ * @size: size of buf
+ * @ascii: if true convert from unicode to ascii characters
+ *
+ * Return 0 in case of success, non-zero otherwise
+ */
+int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index, u8 *buf,
+                                u32 size, bool ascii)
+{
+        int err = 0;
+
+        err = ufshcd_read_desc(hba,
+                                QUERY_DESC_IDN_STRING, desc_index, buf, size);
+
+        if (err) {
+                dev_err(hba->dev, "%s: reading String Desc failed after %d retries. err = %d\n",
+                        __func__, QUERY_REQ_RETRIES, err);
+                goto out;
+        }
+
+        if (ascii) {
+                int desc_len;
+                int ascii_len;
+                int i;
+                char *buff_ascii;
+
+                desc_len = buf[0];
+                /* remove header and divide by 2 to move from UTF16 to UTF8 */
+                ascii_len = (desc_len - QUERY_DESC_HDR_SIZE) / 2 + 1;
+                if (size < ascii_len + QUERY_DESC_HDR_SIZE) {
+                        dev_err(hba->dev, "%s: buffer allocated size is too small\n",
+                                        __func__);
+                        err = -ENOMEM;
+                        goto out;
+                }
+
+                buff_ascii = kmalloc(ascii_len, GFP_KERNEL);
+                if (!buff_ascii) {
+                        err = -ENOMEM;
+                        goto out_free_buff;
+                }
+
+                /*
+                 * the descriptor contains string in UTF16 format
+                 * we need to convert to utf-8 so it can be displayed
+                 */
+                utf16s_to_utf8s((wchar_t *)&buf[QUERY_DESC_HDR_SIZE],
+                                desc_len - QUERY_DESC_HDR_SIZE,
+                                UTF16_BIG_ENDIAN, buff_ascii, ascii_len);
+
+                /* replace non-printable or non-ASCII characters with spaces */
+                for (i = 0; i < ascii_len; i++)
+                        ufshcd_remove_non_printable(&buff_ascii[i]);
+
+                memset(buf + QUERY_DESC_HDR_SIZE, 0,
+                                size - QUERY_DESC_HDR_SIZE);
+                memcpy(buf + QUERY_DESC_HDR_SIZE, buff_ascii, ascii_len);
+                buf[QUERY_DESC_LENGTH_OFFSET] = ascii_len + QUERY_DESC_HDR_SIZE;
+out_free_buff:
+                kfree(buff_ascii);
+        }
+out:
+        return err;
+}
+EXPORT_SYMBOL(ufshcd_read_string_desc);
+
 /**
  * ufshcd_read_unit_desc_param - read the specified unit descriptor parameter
  * @hba: Pointer to adapter instance
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index a6d35724ccdc..54e13ccb5754 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -678,6 +678,13 @@ static inline int ufshcd_dme_peer_get(struct ufs_hba *hba,
         return ufshcd_dme_get_attr(hba, attr_sel, mib_val, DME_PEER);
 }
 
+int ufshcd_read_device_desc(struct ufs_hba *hba, u8 *buf, u32 size);
+
+#define ASCII_STD true
+
+int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index, u8 *buf,
+                                u32 size, bool ascii);
+
 /* Expose Query-Request API */
 int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
         enum flag_idn idn, bool *flag_res);