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>

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)))
 

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

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);