From: Han Xu <han.xu@nxp.com>
To: Yunhui Cui <B56489@freescale.com>,
        "computersforpeace@gmail.com" <computersforpeace@gmail.com>,
        "han.xu@freescale.com" <han.xu@freescale.com>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        Yao Yuan <yao.yuan@nxp.com>, "Yunhui Cui" <yunhui.cui@nxp.com>,
        "dwmw2@infradead.org" <dwmw2@infradead.org>
Subject: Re: [PATCH 6/9] mtd: spi-nor: Support R/W for S25FS-S family flash
Thread-Topic: [PATCH 6/9] mtd: spi-nor: Support R/W for S25FS-S family flash
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Date: Wed, 20 Apr 2016 22:34:27 +0000
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________________________________________
From: Yunhui Cui <B56489@freescale.com>
Sent: Wednesday, April 13, 2016 9:50 PM
To: dwmw2@infradead.org; computersforpeace@gmail.com; han.xu@freescale.com
Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
Subject: [PATCH 6/9] mtd: spi-nor: Support R/W for S25FS-S family flash

From: Yunhui Cui <yunhui.cui@nxp.com>

With the physical sectors combination, S25FS-S family flash
requires some special operations for read/write functions.

Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 59 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 157841d..91ee920 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -39,6 +39,10 @@

 #define SPI_NOR_MAX_ID_LEN     6
 #define SPI_NOR_MAX_ADDR_WIDTH 4
+/* Added for S25FS-S family flash */
+#define SPINOR_CONFIG_REG3_OFFSET      0x800004
+#define CR3V_4KB_ERASE_UNABLE  0x8
+#define SPINOR_S25FS_FAMILY_ID 0x81

 struct flash_info {
        char            *name;
@@ -78,6 +82,7 @@ struct flash_info {
 };

 #define JEDEC_MFR(info)        ((info)->id[0])
+#define EXT_ID(info)   ((info)->id[5])

 static const struct flash_info *spi_nor_match_id(const char *name);

@@ -881,6 +886,7 @@ static const struct flash_info spi_nor_ids[] = {
         */
        { "s25sl032p",  INFO(0x010215, 0x4d00,  64 * 1024,  64, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25sl064p",  INFO(0x010216, 0x4d00,  64 * 1024, 128, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
+       { "s25fs256s1", INFO6(0x010219, 0x4d0181, 64 * 1024, 512, 0)},
        { "s25fl256s0", INFO(0x010219, 0x4d00, 256 * 1024, 128, 0) },
        { "s25fl256s1", INFO(0x010219, 0x4d01,  64 * 1024, 512, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "s25fl512s",  INFO(0x010220, 0x4d00, 256 * 1024, 256, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
@@ -1018,6 +1024,53 @@ static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
        return ERR_PTR(-ENODEV);
 }

+/*
+ * The S25FS-S family physical sectors may be configured as a
+ * hybrid combination of eight 4-kB parameter sectors
+ * at the top or bottom of the address space with all
+ * but one of the remaining sectors being uniform size.
+ * The Parameter Sector Erase commands (20h or 21h) must
+ * be used to erase the 4-kB parameter sectors individually.
+ * The Sector (uniform sector) Erase commands (D8h or DCh)
+ * must be used to erase any of the remaining
+ * sectors, including the portion of highest or lowest address
+ * sector that is not overlaid by the parameter sectors.
+ * The uniform sector erase command has no effect on parameter sectors.
+ */
+static int spansion_s25fs_disable_4kb_erase(struct spi_nor *nor)
+{
+       struct fsl_qspi *q;
+       u32 cr3v_addr  = SPINOR_CONFIG_REG3_OFFSET;
+       u8 cr3v = 0x0;
+       int ret = 0x0;
+
+       q = nor->priv;
+
+       nor->cmd_buf[2] = cr3v_addr >> 16;
+       nor->cmd_buf[1] = cr3v_addr >> 8;
+       nor->cmd_buf[0] = cr3v_addr >> 0;

I feel it's hacking code.

Hi Brian, do we have any plan to support this special case? The RDAR(
Read Any Register) needs an extra address parameter.

+
+       ret = nor->read_reg(nor, SPINOR_OP_SPANSION_RDAR, &cr3v, 1);
+       if (ret)
+               return ret;
+       if (cr3v & CR3V_4KB_ERASE_UNABLE)
+               return 0;
+       ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0);
+       if (ret)
+               return ret;
+       cr3v = CR3V_4KB_ERASE_UNABLE;
+       nor->program_opcode = SPINOR_OP_SPANSION_WRAR;
+       nor->write(nor, cr3v_addr, 1, NULL, &cr3v);
+
+       ret = nor->read_reg(nor, SPINOR_OP_SPANSION_RDAR, &cr3v, 1);
+       if (ret)
+               return ret;
+       if (!(cr3v & CR3V_4KB_ERASE_UNABLE))
+               return -EPERM;
+
+       return 0;
+}
+
 static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
                        size_t *retlen, u_char *buf)
 {
@@ -1311,6 +1364,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
                spi_nor_wait_till_ready(nor);
        }

+       if (EXT_ID(info) == SPINOR_S25FS_FAMILY_ID) {
+               ret = spansion_s25fs_disable_4kb_erase(nor);
+               if (ret)
+                       return ret;
+       }
+
        if (!mtd->name)
                mtd->name = dev_name(dev);
        mtd->priv = nor;
--
2.1.0.27.g96db324