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Date:   Wed, 17 Oct 2018 11:52:37 +0200
From:   Boris Brezillon <boris.brezillon@bootlin.com>
To:     Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>
Cc:     Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        "marek.vasut@gmail.com" <marek.vasut@gmail.com>,
        "dwmw2@infradead.org" <dwmw2@infradead.org>,
        "computersforpeace@gmail.com" <computersforpeace@gmail.com>,
        "richard@nod.at" <richard@nod.at>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "nicolas.ferre@microchip.com" <nicolas.ferre@microchip.com>,
        "cyrille.pitchen@microchip.com" <cyrille.pitchen@microchip.com>,
        "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "Cristian.Birsan@microchip.com" <Cristian.Birsan@microchip.com>
Subject: Re: [PATCH v3 1/2] mtd: spi-nor: add support to non-uniform SFDP
 SPI NOR flash memories
Message-ID: <20181017115237.07310b74@bbrezillon>
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On Wed, 17 Oct 2018 07:46:30 +0000
Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com> wrote:

> Hi Boris,
> 
> > -----Original Message-----
> > From: Boris Brezillon [mailto:boris.brezillon@bootlin.com]
> > Sent: Wednesday, October 17, 2018 1:00 PM
> > To: Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com>
> > Cc: Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>; Tudor Ambarus
> > <tudor.ambarus@microchip.com>; marek.vasut@gmail.com;
> > dwmw2@infradead.org; computersforpeace@gmail.com; richard@nod.at;
> > linux-kernel@vger.kernel.org; nicolas.ferre@microchip.com;
> > cyrille.pitchen@microchip.com; linux-mtd@lists.infradead.org; linux-arm-
> > kernel@lists.infradead.org; Cristian.Birsan@microchip.com
> > Subject: Re: [PATCH v3 1/2] mtd: spi-nor: add support to non-uniform SFDP SPI
> > NOR flash memories
> > 
> > On Wed, 17 Oct 2018 09:10:45 +0200
> > Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> >   
> > > On Wed, 17 Oct 2018 09:07:24 +0200
> > > Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> > >  
> > > > On Wed, 17 Oct 2018 02:07:43 +0000
> > > > Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com> wrote:
> > > >  
> > > > > >  
> > > > > Actually there is no entry of s25fs512s in current spi-nor.c file.
> > > > > For my connected flash part, jedec ID read points to s25fl512s. I
> > > > > have asked my board team to confirm the name of exact connected
> > > > > flash part. When I check the data sheet of s25fs512s, it also
> > > > > points to the same Jedec ID information. { "s25fl512s",
> > > > > INFO(0x010220, 0x4d00, 256
> > > > > * 1024, 256, ....}
> > > > >
> > > > > But as stated earlier, if I skip reading SFDP or read using 1-1-1
> > > > > protocol then read are always correct. For 1-4-4 protocol read are
> > > > > wrong and on further debugging found that Read code of 0x6C is
> > > > > being send as opcode instead of 0xEC.
> > > > >
> > > > > If I revert this patch, reads are working fine.  
> > > >
> > > > Can you try with the following patch?
> > > >  
> > >
> > > Hm, nevermind. The problem is actually not related to 4B vs non-4B
> > > mode but 1-1-4 vs 1-4-4 modes.  
> Yes, that's only I have stated in my first mail that instead of 1-4-4 mode read opcode is being sent for 1-1-4 mode.
> > >  
> > 
> > Can you try with this patch applied?
> >   
> With suggested patch, read for protocol 1-4-4 working correctly.
> 
> 	[    1.625360] m25p80 spi0.0: found s25fl512s, expected m25p80                                                                   
> 	[    1.631094] m25p80 spi0.0: failed to parse SMPT (err = -22)                                                                   
> 	[    1.636661] 261 8c4c780 opcode(read:eb, pp:2, erase:d8)                                                                       
> 	[    1.641878] 266 8c4c780 opcode(read:ec, pp:12, erase:dc)                                                                      
> 	[    1.647200] m25p80 spi0.0: s25fl512s (65536 Kbytes)         
> 

Okay, let's try this one to see why the SMPT parsing fails.

--->8---
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 9407ca5f9443..564882c87641 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2855,23 +2855,31 @@ static u8 spi_nor_smpt_read_dummy(const struct spi_nor *nor, const u32 settings)
  * spi_nor_get_map_in_use() - get the configuration map in use
  * @nor:       pointer to a 'struct spi_nor'
  * @smpt:      pointer to the sector map parameter table
+ * @smpt_len:  number of entries in the smpt array
  */
-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;
 
+       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++) {
+               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]);
@@ -2887,18 +2895,40 @@ static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt)
                 * Configuration that is currently in use.
                 */
                map_id = map_id << 1 | !!(data_byte & read_data_mask);
+               map_id_is_valid = true;
                i = i + 2;
        }
 
+       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__);
+
        /* Find the matching configuration map */
-       while (SMPT_MAP_ID(smpt[i]) != map_id) {
-               if (smpt[i] & SMPT_DESC_END)
-                       goto out;
+       for (nmaps = 0; i < smpt_len; nmaps++) {
+               if (!(smpt[i] & SMPT_DESC_TYPE_MAP))
+                       continue;
+
+               if (!map_id_is_valid) {
+                       /*
+                        * Command descriptors are optional but if we didn't
+                        * find any, we should ensure we have only one map.
+                        */
+                       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;
        /* fall through */
 out:
        nor->addr_width = addr_width;
@@ -3020,7 +3050,7 @@ static int spi_nor_parse_smpt(struct spi_nor *nor,
        for (i = 0; i < smpt_header->length; i++)
                smpt[i] = le32_to_cpu(smpt[i]);
 
-       sector_map = spi_nor_get_map_in_use(nor, smpt);
+       sector_map = spi_nor_get_map_in_use(nor, smpt, smpt_header->length);
        if (!sector_map) {
                ret = -EINVAL;
                goto out;
@@ -3132,6 +3162,17 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
                switch (SFDP_PARAM_HEADER_ID(param_header)) {
                case SFDP_SECTOR_MAP_ID:
                        err = spi_nor_parse_smpt(nor, param_header);
+                       if (err) {
+                               dev_warn(dev,
+                                        "failed to parse SMPT (err = %d)\n",
+                                        err);
+                               /*
+                                * SMPT parsing is optional, let's not drop
+                                * all information we extracted so far just
+                                * because it failed.
+                                */
+                               err = 0;
+                       }
                        break;
 
                default: