Hi,

-----Original Message-----
From: Boris Brezillon [mailto:boris.brezillon at bootlin.com]
Sent: Monday, October 22, 2018 3:57 PM
To: Yogesh Narayan Gaur <redacted>
Cc: Tudor Ambarus <redacted>; richard at nod.at; Mark
Brown [off-list ref]; linux-kernel at vger.kernel.org;
nicolas.ferre at microchip.com; marek.vasut at gmail.com;
cyrille.pitchen at microchip.com; linux-mtd at lists.infradead.org;
Cristian.Birsan at microchip.com; Cyrille Pitchen [off-list ref];
computersforpeace at gmail.com; dwmw2 at infradead.org; linux-arm-
kernel at lists.infradead.org
Subject: Re: [PATCH v3 1/2] mtd: spi-nor: add support to non-uniform SFDP SPI
NOR flash memories

On Mon, 22 Oct 2018 10:03:55 +0000
Yogesh Narayan Gaur [off-list ref] wrote:

quoted

--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c

@@ -2863,26 +2863,36 @@ static u8 spi_nor_smpt_read_dummy(const struct

spi_nor *nor, const u32 settings)

quoted

  * @nor:       pointer to a 'struct spi_nor'
  * @smpt:      pointer to the sector map parameter table
  */
-static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const
u32 *smpt)
+static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const
+u32 *smpt, u32 smpt_len)
 {
        const u32 *ret = NULL;
-       u32 i, addr;
+       u32 i, addr, nmaps;
        int err;
        u8 addr_width, read_opcode, read_dummy;
        u8 read_data_mask, data_byte, map_id;
+       bool map_id_is_valid = false;

        addr_width = nor->addr_width;
        read_dummy = nor->read_dummy;
        read_opcode = nor->read_opcode;

+       pr_info("Start [addr_width:%08x, read_dumy:%0x8,
+ read_opcode:%08x]\n", nor->addr_width, nor->read_dummy,
+ nor->read_opcode);
+
+       for (i = 0; i<smpt_len; i++)
+               pr_info("%s:%i smpt[%d]=%08x\n", __func__, __LINE__,
+ i, smpt[i]);
+
        map_id = 0;
-       i = 0;
        /* Determine if there are any optional Detection Command Descriptors */
-       while (!(smpt[i] & SMPT_DESC_TYPE_MAP)) {
+       for (i = 0; i< smpt_len; i++) {

				   ^ i += 2) {

quoted

+               if ((smpt[i] & SMPT_DESC_TYPE_MAP))
+                       break;
+
                read_data_mask = SMPT_CMD_READ_DATA(smpt[i]);
                nor->addr_width = spi_nor_smpt_addr_width(nor, smpt[i]);
                nor->read_dummy = spi_nor_smpt_read_dummy(nor, smpt[i]);
                nor->read_opcode = SMPT_CMD_OPCODE(smpt[i]);
+               pr_info("smpt[%d]=[addr_width:%08x, read_dumy:%0x8,
+ read_opcode:%08x]\n", i, nor->addr_width, nor->read_dummy,
+ nor->read_opcode);
+
                addr = smpt[i + 1];

                err = spi_nor_read_raw(nor, addr, 1, &data_byte); @@
-2894,18 +2904,36 @@ static const u32 *spi_nor_get_map_in_use(struct

spi_nor *nor, const u32 *smpt)

quoted

                 * Configuration that is currently in use.
                 */
                map_id = map_id << 1 | !!(data_byte & read_data_mask);
+               map_id_is_valid = true;
                i = i + 2;

Drop the above line (i = i + 2).

[    1.632190] Start [addr_width:00000000, read_dumy:08, read_opcode:00000000]                                                   
[    1.639148] spi_nor_get_map_in_use:2882 smpt[0]=08ff65fc                                                                      
[    1.644451] spi_nor_get_map_in_use:2882 smpt[1]=00000004                                                                      
[    1.649755] spi_nor_get_map_in_use:2882 smpt[2]=04ff65fc                                                                      
[    1.655057] spi_nor_get_map_in_use:2882 smpt[3]=00000002                                                                      
[    1.660360] spi_nor_get_map_in_use:2882 smpt[4]=02ff65fd                                                                      
[    1.665662] spi_nor_get_map_in_use:2882 smpt[5]=00000004                                                                      
[    1.670965] spi_nor_get_map_in_use:2882 smpt[6]=ff0201fe                                                                      
[    1.676267] spi_nor_get_map_in_use:2882 smpt[7]=00007ff1                                                                      
[    1.681571] spi_nor_get_map_in_use:2882 smpt[8]=00037ff4                                                                      
[    1.686874] spi_nor_get_map_in_use:2882 smpt[9]=03fbfff4                                                                      
[    1.692176] spi_nor_get_map_in_use:2882 smpt[10]=ff0203fe                                                                     
[    1.697566] spi_nor_get_map_in_use:2882 smpt[11]=03fbfff4                                                                     
[    1.702954] spi_nor_get_map_in_use:2882 smpt[12]=00037ff4                                                                     
[    1.708343] spi_nor_get_map_in_use:2882 smpt[13]=00007ff1                                                                     
[    1.713732] spi_nor_get_map_in_use:2882 smpt[14]=ff0005ff                                                                     
[    1.719120] spi_nor_get_map_in_use:2882 smpt[15]=03fffff4                                                                     
[    1.724509] smpt[0]=[addr_width:00000000, read_dumy:08, read_opcode:00000065]                                                 
[    1.731650] smpt[1]=[addr_width:00000000, read_dumy:08, read_opcode:00000000]                                                 
[    1.738791] smpt[2]=[addr_width:00000000, read_dumy:08, read_opcode:00000065]                                                 
[    1.745932] spi_nor_get_map_in_use:2911 map_id=0 smpt_len:16 i=:3                                                             
[    1.752018] End [addr_width:00000000, read_dumy:08, read_opcode:00000065]         

Also, one more thing when we are returning from the function, we are over-writing the values of addr_widthm read_dummy and read_opcode.
Is this correct?

out:
        nor->addr_width = addr_width;
        nor->read_dummy = read_dummy;
        nor->read_opcode = read_opcode;
        return ret;
}

--
Regards
Yogesh Gaur

quoted

        }

-       /* Find the matching configuration map */
-       while (SMPT_MAP_ID(smpt[i]) != map_id) {
-               if (smpt[i] & SMPT_DESC_END)
-                       goto out;
+       if (map_id_is_valid)
+               pr_info("%s:%i map_id=%d\n", __func__, __LINE__, map_id);
+       else
+               pr_info("%s:%i NO map_id\n", __func__, __LINE__);
+
+       for (nmaps = 0; i< smpt_len; nmaps++) {
+               if((smpt[i] & SMPT_DESC_TYPE_MAP))
+                       continue;
+
+               if(!map_id_is_valid) {
+                       if (nmaps) {
+                               ret = NULL;
+                               break;
+                       }
+
+                       ret = smpt+i;
+               } else if (map_id == SMPT_MAP_ID(smpt[i])) {
+                       ret = smpt+i;
+                       break;
+               }
+
                /* increment the table index to the next map */
                i += SMPT_MAP_REGION_COUNT(smpt[i]) + 1;
        }

-       ret = smpt + i;
+       pr_info("End [addr_width:%08x, read_dumy:%0x8,
+ read_opcode:%08x]\n", nor->addr_width, nor->read_dummy,
+ nor->read_opcode);
        /* fall through */
 out:
        nor->addr_width = addr_width;