Message-Id: <1468527505-22767-1-git-send-email-ricardo.ribalda@gmail.com>
Date:	Thu, 14 Jul 2016 22:18:25 +0200
From:	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
To:	David Woodhouse <dwmw2@...radead.org>,
	Brian Norris <computersforpeace@...il.com>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>,
	Stephen Warren <swarren@...dia.com>,
	Jagan Teki <jteki@...nedev.com>, Vignesh R <vigneshr@...com>,
	Marek Vasut <marex@...x.de>,
	Ezequiel García <ezequiel@...guardiasur.com.ar>,
	Rafał Miłecki <zajec5@...il.com>,
	Furquan Shaikh <furquan@...gle.com>,
	Cyrille Pitchen <cyrille.pitchen@...el.com>,
	linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
Subject: [PATCH v4] mtd: spi-nor: Add support for S3AN spi-nor devices

Xilinx Spartan-3AN FPGAs contain an In-System Flash where they keep
their configuration data and (optionally) some user data.

The protocol of this flash follows most of the spi-nor standard. With
the following differences:

- Page size might not be a power of two.
- The address calculation (default addressing mode).
- The spi nor commands used.

Protocol is described on Xilinx User Guide UG333

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
---
v4: 
-Rebase on top of l2-mtd/master

v3: 
-Rebase on top of mtd-next
-Rename ADDR_NATIVE to ADDR_DEFAULT to follow UG333 naming
-Fix bug on probe

v2: Suggested by Brian Norris <computersforpeace@...il.com>

-Remove inline qualifier
-Improve documentation of Default Addressing Mode
-Convert function callbacks into SNOR_F_
-Fix missmatch braces
-Improve documentation of SPI_S3AN flag

 drivers/mtd/devices/m25p80.c  |   3 ++
 drivers/mtd/spi-nor/spi-nor.c | 110 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/mtd/spi-nor.h   |  26 ++++++++++
 3 files changed, 136 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 9cf7fcd28034..a44465f2b73d 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -49,6 +49,9 @@ static int m25p80_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
 
 static void m25p_addr2cmd(struct spi_nor *nor, unsigned int addr, u8 *cmd)
 {
+	if (nor->flags & SNOR_F_S3AN_ADDR_DEFAULT)
+		addr = spi_nor_s3an_addr_convert(nor, addr);
+
 	/* opcode is in cmd[0] */
 	cmd[1] = addr >> (nor->addr_width * 8 -  8);
 	cmd[2] = addr >> (nor->addr_width * 8 - 16);
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d0fc165d7d66..dce0a2f156e1 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -75,6 +75,12 @@ struct flash_info {
 					 * bit. Must be used with
 					 * SPI_NOR_HAS_LOCK.
 					 */
+#define	SPI_S3AN		BIT(10)	/*
+					 * Xilinx Spartan 3AN In-System Flash
+					 * (MFR cannot be used for probing
+					 * because it has the same value as
+					 * ATMEL flashes)
+					*/
 };
 
 #define JEDEC_MFR(info)	((info)->id[0])
@@ -217,6 +223,21 @@ static inline int set_4byte(struct spi_nor *nor, const struct flash_info *info,
 		return nor->write_reg(nor, SPINOR_OP_BRWR, nor->cmd_buf, 1);
 	}
 }
+
+static int s3an_sr_ready(struct spi_nor *nor)
+{
+	int ret;
+	u8 val;
+
+	ret = nor->read_reg(nor, SPINOR_OP_XRDSR, &val, 1);
+	if (ret < 0) {
+		pr_err("error %d reading XRDSR\n", (int) ret);
+		return ret;
+	}
+
+	return !!(val & XSR_RDY);
+}
+
 static inline int spi_nor_sr_ready(struct spi_nor *nor)
 {
 	int sr = read_sr(nor);
@@ -238,7 +259,9 @@ static inline int spi_nor_fsr_ready(struct spi_nor *nor)
 static int spi_nor_ready(struct spi_nor *nor)
 {
 	int sr, fsr;
-	sr = spi_nor_sr_ready(nor);
+
+	sr = nor->flags & SNOR_F_READY_XSR_RDY ? s3an_sr_ready(nor) :
+						 spi_nor_sr_ready(nor);
 	if (sr < 0)
 		return sr;
 	fsr = nor->flags & SNOR_F_USE_FSR ? spi_nor_fsr_ready(nor) : 1;
@@ -320,6 +343,23 @@ static void spi_nor_unlock_and_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
 }
 
 /*
+ * This code converts an address to the Default Address Mode, that has non
+ * power of two page sizes. We must support this mode because it is the default
+ * mode supported by Xilinx tools, it can access the whole flash area and
+ * changing over to the Power-of-two mode is irreversible and corrupts the
+ * original data.
+ */
+unsigned int spi_nor_s3an_addr_convert(struct spi_nor *nor, unsigned int addr)
+{
+	unsigned int offset;
+
+	offset = (nor->page_size == 264) ? (addr % 264) : (addr % 528);
+
+	return ((addr - offset) << 1) | offset;
+}
+EXPORT_SYMBOL_GPL(spi_nor_s3an_addr_convert);
+
+/*
  * Initiate the erasure of a single sector
  */
 static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
@@ -330,6 +370,9 @@ static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
 	if (nor->erase)
 		return nor->erase(nor, addr);
 
+	if (nor->flags & SNOR_F_S3AN_ADDR_DEFAULT)
+		addr = spi_nor_s3an_addr_convert(nor, addr);
+
 	/*
 	 * Default implementation, if driver doesn't have a specialized HW
 	 * control
@@ -368,7 +411,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 		return ret;
 
 	/* whole-chip erase? */
-	if (len == mtd->size) {
+	if (len == mtd->size && !(nor->flags & SNOR_F_NO_OP_CHIP_ERASE)) {
 		unsigned long timeout;
 
 		write_enable(nor);
@@ -782,6 +825,19 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 		.addr_width = (_addr_width),				\
 		.flags = (_flags),
 
+#define S3AN_INFO(_jedec_id, _n_sectors, _page_size)			\
+		.id = {							\
+			((_jedec_id) >> 16) & 0xff,			\
+			((_jedec_id) >> 8) & 0xff,			\
+			(_jedec_id) & 0xff				\
+			},						\
+		.id_len = 3,						\
+		.sector_size = (8*_page_size),				\
+		.n_sectors = (_n_sectors),				\
+		.page_size = _page_size,				\
+		.addr_width = 3,					\
+		.flags = SPI_NOR_NO_FR | SPI_S3AN,
+
 /* NOTE: double check command sets and memory organization when you add
  * more nor chips.  This current list focusses on newer chips, which
  * have been converging on command sets which including JEDEC ID.
@@ -1009,6 +1065,13 @@ static const struct flash_info spi_nor_ids[] = {
 	{ "cat25c09", CAT25_INFO( 128, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
 	{ "cat25c17", CAT25_INFO( 256, 8, 32, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
 	{ "cat25128", CAT25_INFO(2048, 8, 64, 2, SPI_NOR_NO_ERASE | SPI_NOR_NO_FR) },
+
+	/* Xilinx S3AN Internal Flash */
+	{ "3S50AN", S3AN_INFO(0x1f2200, 64, 264) },
+	{ "3S200AN", S3AN_INFO(0x1f2400, 256, 264) },
+	{ "3S400AN", S3AN_INFO(0x1f2400, 256, 264) },
+	{ "3S700AN", S3AN_INFO(0x1f2500, 512, 264) },
+	{ "3S1400AN", S3AN_INFO(0x1f2600, 512, 528) },
 	{ },
 };
 
@@ -1171,7 +1234,13 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
 	for (i = 0; i < len; ) {
 		ssize_t written;
 
-		page_offset = (to + i) & (nor->page_size - 1);
+		if (hweight32(nor->page_size) == 1)
+			page_offset = to & (nor->page_size - 1);
+		else {
+			uint64_t aux = to;
+
+			page_offset = do_div(aux, nor->page_size);
+		}
 		WARN_ONCE(page_offset,
 			  "Writing at offset %zu into a NOR page. Writing partial pages may decrease reliability and increase wear of NOR flash.",
 			  page_offset);
@@ -1300,6 +1369,35 @@ static int spi_nor_check(struct spi_nor *nor)
 	return 0;
 }
 
+static int s3an_nor_scan(const struct flash_info *info, struct spi_nor *nor)
+{
+	int ret;
+	u8 val;
+
+	ret = nor->read_reg(nor, SPINOR_OP_XRDSR, &val, 1);
+	if (ret < 0) {
+		pr_err("error %d reading XRDSR\n", (int) ret);
+		return ret;
+	}
+
+	nor->erase_opcode = SPINOR_OP_XSE;
+	nor->program_opcode = SPINOR_OP_XPP;
+	nor->read_opcode = SPINOR_OP_READ;
+	nor->flags |= SNOR_F_NO_OP_CHIP_ERASE | SNOR_F_READY_XSR_RDY;
+
+	/* Flash in Power of 2 mode */
+	if (val & XSR_PAGESIZE) {
+		nor->page_size = (nor->page_size == 264) ? 256 : 512;
+		nor->mtd.writebufsize = nor->page_size;
+		nor->mtd.size = 8 * nor->page_size * info->n_sectors;
+		nor->mtd.erasesize = 8 * nor->page_size;
+	} else {
+		nor->flags |= SNOR_F_S3AN_ADDR_DEFAULT;
+	}
+
+	return 0;
+}
+
 int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 {
 	const struct flash_info *info = NULL;
@@ -1505,6 +1603,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 
 	nor->read_dummy = spi_nor_read_dummy_cycles(nor);
 
+	if (info->flags & SPI_S3AN) {
+		ret = s3an_nor_scan(info, nor);
+		if (ret)
+			return ret;
+	}
+
 	dev_info(dev, "%s (%lld Kbytes)\n", info->name,
 			(long long)mtd->size >> 10);
 
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index c425c7b4c2a0..6378de414bca 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -68,6 +68,15 @@
 #define SPINOR_OP_WRDI		0x04	/* Write disable */
 #define SPINOR_OP_AAI_WP	0xad	/* Auto address increment word program */
 
+/* Used for S3AN flashes only */
+#define SPINOR_OP_XSE		0x50	/* Sector erase */
+#define SPINOR_OP_XPP		0x82	/* Page program */
+#define SPINOR_OP_XRDSR		0xd7	/* Read status register */
+
+#define XSR_PAGESIZE		BIT(0)	/* Page size in Po2 or Linear */
+#define XSR_RDY			BIT(7)	/* Ready */
+
+
 /* Used for Macronix and Winbond flashes. */
 #define SPINOR_OP_EN4B		0xb7	/* Enter 4-byte mode */
 #define SPINOR_OP_EX4B		0xe9	/* Exit 4-byte mode */
@@ -119,6 +128,9 @@ enum spi_nor_ops {
 enum spi_nor_option_flags {
 	SNOR_F_USE_FSR		= BIT(0),
 	SNOR_F_HAS_SR_TB	= BIT(1),
+	SNOR_F_NO_OP_CHIP_ERASE	= BIT(2),
+	SNOR_F_S3AN_ADDR_DEFAULT = BIT(3),
+	SNOR_F_READY_XSR_RDY	= BIT(4),
 };
 
 /**
@@ -197,6 +209,20 @@ static inline struct device_node *spi_nor_get_flash_node(struct spi_nor *nor)
 	return mtd_get_of_node(&nor->mtd);
 }
 
+
+/**
+ * spi_nor_s3an_addr_convert() - convert an address to Default Address Mode
+ * @nor:	the spi_nor structure
+ * @addr:	the contiguous address value
+ *
+ * Spartan-3AN In-System Flash requires an special address mode to access its
+ * whole Flash area. This address mode, named Default Address Mode by Xilinx,
+ * has non power of two page sizes.
+ *
+ * Return: Address in Default Address Mode
+ */
+unsigned int spi_nor_s3an_addr_convert(struct spi_nor *nor, unsigned int addr);
+
 /**
  * spi_nor_scan() - scan the SPI NOR
  * @nor:	the spi_nor structure
-- 
2.8.1

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