[PATCH v2] axs_nand - add driver for NAND controller used on Synopsys AXS dev boards
From: Alexey Brodkin
Date: Fri Apr 04 2014 - 03:38:39 EST
Signed-off-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
Reviewed-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx>
Cc: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
cc: Brian Norris <computersforpeace@xxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Francois Bedard <fbedard@xxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: devicetree@xxxxxxxxxxxxxxx
---
In this re-spin I addressed Ezequiel comments.
Changes compared to v1:
* Minor code clean-up
* Fixed typos
* axs_flag_is_set() replaced with axs_flag_wait_and_reset()
* axs_flag_wait_and_reset() has built-in check for timeout instead of endless
while() loop initially used
Documentation/devicetree/bindings/mtd/axs-nand.txt | 17 +
drivers/mtd/nand/Kconfig | 6 +
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/axs_nand.c | 411 +++++++++++++++++++++
4 files changed, 435 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mtd/axs-nand.txt
create mode 100644 drivers/mtd/nand/axs_nand.c
diff --git a/Documentation/devicetree/bindings/mtd/axs-nand.txt b/Documentation/devicetree/bindings/mtd/axs-nand.txt
new file mode 100644
index 0000000..c522b7f
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/axs-nand.txt
@@ -0,0 +1,17 @@
+* Synopsys AXS NAND controller
+
+Required properties:
+ - compatible: must be "snps,axs-nand"
+ - reg: physical base address and size of the registers map
+
+The device tree may optionally contain sub-nodes describing partitions of the
+address space. See partition.txt for more detail.
+
+Examples:
+
+flash@0x16000 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ compatible = "snps,axs-nand";
+ reg = < 0x16000 0x200 >;
+};
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 93ae6a6..3661822 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -510,4 +510,10 @@ config MTD_NAND_XWAY
Enables support for NAND Flash chips on Lantiq XWAY SoCs. NAND is attached
to the External Bus Unit (EBU).
+config MTD_NAND_AXS
+ tristate "Support for NAND on Synopsys AXS development board"
+ help
+ Enables support for NAND Flash chips on Synopsys AXS development
+ boards.
+
endif # MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index 542b568..635a918 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -49,5 +49,6 @@ obj-$(CONFIG_MTD_NAND_JZ4740) += jz4740_nand.o
obj-$(CONFIG_MTD_NAND_GPMI_NAND) += gpmi-nand/
obj-$(CONFIG_MTD_NAND_XWAY) += xway_nand.o
obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH) += bcm47xxnflash/
+obj-$(CONFIG_MTD_NAND_AXS) += axs_nand.o
nand-objs := nand_base.o nand_bbt.o
diff --git a/drivers/mtd/nand/axs_nand.c b/drivers/mtd/nand/axs_nand.c
new file mode 100644
index 0000000..9ee21b6
--- /dev/null
+++ b/drivers/mtd/nand/axs_nand.c
@@ -0,0 +1,411 @@
+/*
+ * Copyright (C) 2014 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Driver for NAND controller on Synopsys AXS development board.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License v2. See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+
+/*
+ * There's an issue with DMA'd data if data buffer is cached.
+ * So to make NAND storage available for now we'll map data buffer in
+ * uncached memory.
+ *
+ * As soon as issue with cached buffer is resolved following define to be
+ * removed as well as sources it enables.
+ */
+#define DATA_BUFFER_UNCACHED
+
+#define BUS_WIDTH 8 /* AXI data bus width in bytes */
+
+/* DMA buffer descriptor masks */
+#define BD_STAT_OWN (1 << 31)
+#define BD_STAT_BD_FIRST (1 << 3)
+#define BD_STAT_BD_LAST (1 << 2)
+#define BD_SIZES_BUFFER1_MASK 0xfff
+
+#define BD_STAT_BD_COMPLETE (BD_STAT_BD_FIRST | BD_STAT_BD_LAST)
+
+/* Controller command types */
+#define B_CT_ADDRESS (0x0 << 16) /* Address operation */
+#define B_CT_COMMAND (0x1 << 16) /* Command operation */
+#define B_CT_WRITE (0x2 << 16) /* Write operation */
+#define B_CT_READ (0x3 << 16) /* Read operation */
+
+/* Controller command options */
+#define B_WFR (1 << 19) /* 1b - Wait for ready */
+#define B_LC (1 << 18) /* 1b - Last cycle */
+#define B_IWC (1 << 13) /* 1b - Interrupt when complete */
+
+enum {
+ NAND_ISR_DATAREQUIRED = 0,
+ NAND_ISR_TXUNDERFLOW,
+ NAND_ISR_TXOVERFLOW,
+ NAND_ISR_DATAAVAILABLE,
+ NAND_ISR_RXUNDERFLOW,
+ NAND_ISR_RXOVERFLOW,
+ NAND_ISR_TXDMACOMPLETE,
+ NAND_ISR_RXDMACOMPLETE,
+ NAND_ISR_DESCRIPTORUNAVAILABLE,
+ NAND_ISR_CMDDONE,
+ NAND_ISR_CMDAVAILABLE,
+ NAND_ISR_CMDERROR,
+ NAND_ISR_DATATRANSFEROVER,
+ NAND_ISR_NONE
+};
+
+enum {
+ AC_FIFO = 0, /* Address and command fifo */
+ IDMAC_BDADDR = 0x18, /* IDMAC descriptor list base address */
+ INT_STATUS = 0x118, /* Interrupt status register */
+ INT_CLR_STATUS = 0x120 /* Interrupt clear status register */
+};
+
+#define AXS_BUF_SIZE (PAGE_ALIGN(NAND_MAX_PAGESIZE + NAND_MAX_OOBSIZE))
+
+struct asx_nand_bd {
+ __le32 status; /* DES0 */
+ __le32 sizes; /* DES1 */
+ dma_addr_t buffer_ptr0; /* DES2 */
+ dma_addr_t buffer_ptr1; /* DES3 */
+};
+
+struct axs_nand_host {
+ struct nand_chip nand_chip;
+ struct mtd_info mtd;
+ void __iomem *io_base;
+ struct device *dev;
+ struct asx_nand_bd *bd; /* Buffer descriptor */
+ dma_addr_t bd_dma; /* DMA handle for buffer descriptor */
+ uint8_t *db; /* Data buffer */
+ dma_addr_t db_dma; /* DMA handle for data buffer */
+};
+
+/**
+ * reg_set - Sets register with provided value.
+ * @host: Pointer to private data structure.
+ * @reg: Register offset from base address.
+ * @value: Value to set in register.
+ */
+static inline void reg_set(struct axs_nand_host *host, int reg, int value)
+{
+ iowrite32(value, host->io_base + reg);
+}
+
+/**
+ * reg_get - Gets value of specified register.
+ * @host: Pointer to private data structure.
+ * @reg: Register offset from base address.
+ *
+ * returns: Value of requested register.
+ */
+static inline unsigned int reg_get(struct axs_nand_host *host, int reg)
+{
+ return ioread32(host->io_base + reg);
+}
+
+/* Maximum number of milliseconds we wait for flag to appear */
+#define AXS_FLAG_WAIT_DELAY 1000
+
+/**
+ * axs_flag_wait_and_reset - Waits until requested flag in INT_STATUS register
+ * is set by HW and resets it by writing "1" in INT_CLR_STATUS.
+ * @host: Pointer to private data structure.
+ * @flag: Bit/flag offset in INT_STATUS register
+ */
+static void axs_flag_wait_and_reset(struct axs_nand_host *host, int flag)
+{
+ unsigned int i;
+
+ for (i = 0; i < AXS_FLAG_WAIT_DELAY * 100; i++) {
+ unsigned int status = reg_get(host, INT_STATUS);
+
+ if (status & (1 << flag)) {
+ reg_set(host, INT_CLR_STATUS, 1 << flag);
+ return;
+ }
+
+ udelay(10);
+ }
+
+ /*
+ * Since we cannot report this problem any further than
+ * axs_nand_{write|read}_buf() letting user know there's a problem.
+ */
+ dev_err(host->dev, "Waited too long (%d s.) for flag/bit %d\n",
+ AXS_FLAG_WAIT_DELAY, flag);
+}
+
+/**
+ * axs_nand_write_buf - write buffer to chip
+ * @mtd: MTD device structure
+ * @buf: Data buffer
+ * @len: Number of bytes to write
+ */
+static void axs_nand_write_buf(struct mtd_info *mtd,
+ const uint8_t *buf, int len)
+{
+ struct nand_chip *this = mtd->priv;
+ struct axs_nand_host *host = this->priv;
+
+ memcpy(host->db, buf, len);
+#ifndef DATA_BUFFER_UNCACHED
+ dma_sync_single_for_device(host->dev, host->db_dma, len, DMA_TO_DEVICE);
+#endif
+
+ /* Setup buffer descriptor */
+ host->bd->status = BD_STAT_OWN | BD_STAT_BD_COMPLETE;
+ host->bd->sizes = cpu_to_le32(ALIGN(len, BUS_WIDTH) &
+ BD_SIZES_BUFFER1_MASK);
+ host->bd->buffer_ptr0 = cpu_to_le32(host->db_dma);
+ host->bd->buffer_ptr1 = 0;
+
+ /* Issue "write" command */
+ reg_set(host, AC_FIFO, B_CT_WRITE | B_WFR | B_IWC | B_LC | (len - 1));
+
+ /* Wait for NAND command and DMA to complete */
+ axs_flag_wait_and_reset(host, NAND_ISR_CMDDONE);
+ axs_flag_wait_and_reset(host, NAND_ISR_TXDMACOMPLETE);
+}
+
+/**
+ * axs_nand_read_buf - read chip data into buffer
+ * @mtd: MTD device structure
+ * @buf: Buffer to store data
+ * @len: Number of bytes to read
+ */
+static void axs_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+ struct nand_chip *this = mtd->priv;
+ struct axs_nand_host *host = this->priv;
+
+ /* Setup buffer descriptor */
+ host->bd->status = BD_STAT_OWN | BD_STAT_BD_COMPLETE;
+ host->bd->sizes = cpu_to_le32(ALIGN(len, BUS_WIDTH) &
+ BD_SIZES_BUFFER1_MASK);
+ host->bd->buffer_ptr0 = cpu_to_le32(host->db_dma);
+ host->bd->buffer_ptr1 = 0;
+
+ /* Issue "read" command */
+ reg_set(host, AC_FIFO, B_CT_READ | B_WFR | B_IWC | B_LC | (len - 1));
+
+ /* Wait for NAND command and DMA to complete */
+ axs_flag_wait_and_reset(host, NAND_ISR_CMDDONE);
+ axs_flag_wait_and_reset(host, NAND_ISR_RXDMACOMPLETE);
+
+#ifndef DATA_BUFFER_UNCACHED
+ dma_sync_single_for_cpu(host->dev, host->db_dma, len, DMA_FROM_DEVICE);
+#endif
+ if (buf != host->db)
+ memcpy(buf, host->db, len);
+}
+
+/**
+ * axs_nand_read_byte - read one byte from the chip
+ * @mtd: MTD device structure
+ *
+ * returns: read data byte
+ */
+static uint8_t axs_nand_read_byte(struct mtd_info *mtd)
+{
+ struct nand_chip *this = mtd->priv;
+ struct axs_nand_host *host = this->priv;
+
+ axs_nand_read_buf(mtd, host->db, sizeof(uint8_t));
+ return (uint8_t)host->db[0];
+}
+
+/**
+ * axs_nand_read_word - read one word from the chip
+ * @mtd: MTD device structure
+ *
+ * returns: read data word
+ */
+static uint16_t axs_nand_read_word(struct mtd_info *mtd)
+{
+ struct nand_chip *this = mtd->priv;
+ struct axs_nand_host *host = this->priv;
+
+ axs_nand_read_buf(mtd, host->db, sizeof(uint16_t));
+ return (uint16_t)host->db[0];
+}
+
+/**
+ * axs_nand_cmd_ctrl - hardware specific access to control-lines
+ * @mtd: MTD device structure
+ * @cmd: NAND command
+ * @ctrl: NAND control options
+ */
+static void axs_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
+ unsigned int ctrl)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+ struct axs_nand_host *host = nand_chip->priv;
+
+ if (cmd == NAND_CMD_NONE)
+ return;
+
+ cmd = cmd & 0xff;
+
+ switch (ctrl & (NAND_ALE | NAND_CLE)) {
+ /* Address */
+ case NAND_ALE:
+ cmd |= B_CT_ADDRESS;
+ break;
+
+ /* Command */
+ case NAND_CLE:
+ cmd |= B_CT_COMMAND | B_WFR;
+
+ break;
+
+ default:
+ dev_err(host->dev, "Unknown ctrl %#x\n", ctrl);
+ return;
+ }
+
+ reg_set(host, AC_FIFO, cmd | B_LC);
+ axs_flag_wait_and_reset(host, NAND_ISR_CMDDONE);
+}
+
+static int axs_nand_probe(struct platform_device *pdev)
+{
+ struct mtd_part_parser_data ppdata;
+ struct nand_chip *nand_chip;
+ struct axs_nand_host *host;
+ struct resource res_regs;
+ struct mtd_info *mtd;
+ int err;
+
+ if (!pdev->dev.of_node)
+ return -ENODEV;
+
+ /* Get registers base address from device tree */
+ err = of_address_to_resource(pdev->dev.of_node, 0, &res_regs);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to retrieve registers base from device tree\n");
+ return -ENODEV;
+ }
+
+ /* Allocate memory for the device structure (and zero it) */
+ host = kzalloc(sizeof(struct axs_nand_host), GFP_KERNEL);
+ if (!host)
+ return -ENOMEM;
+
+ host->io_base = devm_ioremap_resource(&pdev->dev, &res_regs);
+ if (IS_ERR(host->io_base)) {
+ err = PTR_ERR(host->io_base);
+ goto out;
+ }
+ dev_dbg(&pdev->dev, "Registers base address is 0x%p\n", host->io_base);
+
+ host->bd = dmam_alloc_coherent(&pdev->dev, sizeof(struct asx_nand_bd),
+ &host->bd_dma, GFP_KERNEL);
+ if (!host->bd) {
+ dev_err(&pdev->dev, "Failed to allocate buffer descriptor\n");
+ err = -ENOMEM;
+ goto out;
+ }
+
+ memset(host->bd, 0, sizeof(struct asx_nand_bd));
+
+#ifdef DATA_BUFFER_UNCACHED
+ host->db = dmam_alloc_coherent(&pdev->dev, AXS_BUF_SIZE,
+#else
+ host->db = dmam_alloc_noncoherent(&pdev->dev, AXS_BUF_SIZE,
+#endif
+ &host->db_dma, GFP_KERNEL);
+ if (!host->db) {
+ dev_err(&pdev->dev, "Failed to allocate data buffer\n");
+ err = -ENOMEM;
+ goto out;
+ }
+ dev_dbg(&pdev->dev, "Data buffer mapped @ %p, DMA @ %x\n", host->db,
+ host->db_dma);
+
+ mtd = &host->mtd;
+ nand_chip = &host->nand_chip;
+ host->dev = &pdev->dev;
+
+ nand_chip->priv = host;
+ mtd->priv = nand_chip;
+ mtd->name = "axs_nand";
+ mtd->owner = THIS_MODULE;
+ mtd->dev.parent = &pdev->dev;
+ ppdata.of_node = pdev->dev.of_node;
+
+ nand_chip->cmd_ctrl = axs_nand_cmd_ctrl;
+ nand_chip->read_byte = axs_nand_read_byte;
+ nand_chip->read_word = axs_nand_read_word;
+ nand_chip->write_buf = axs_nand_write_buf;
+ nand_chip->read_buf = axs_nand_read_buf;
+ nand_chip->ecc.mode = NAND_ECC_SOFT;
+
+ dev_set_drvdata(&pdev->dev, host);
+
+ reg_set(host, IDMAC_BDADDR, host->bd_dma);
+
+ err = nand_scan(mtd, 1);
+ if (err)
+ goto out1;
+
+ err = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
+ if (!err)
+ return err;
+
+ nand_release(mtd);
+
+out1:
+ dev_set_drvdata(&pdev->dev, NULL);
+out:
+ kfree(host);
+ return err;
+}
+
+static int axs_nand_remove(struct platform_device *ofdev)
+{
+ struct axs_nand_host *host = dev_get_drvdata(&ofdev->dev);
+ struct mtd_info *mtd = &host->mtd;
+
+ nand_release(mtd);
+ dev_set_drvdata(&ofdev->dev, NULL);
+ kfree(host);
+
+ return 0;
+}
+
+static const struct of_device_id axs_nand_dt_ids[] = {
+ { .compatible = "snps,axs-nand", },
+ { /* Sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, axs_nand_match);
+
+static struct platform_driver axs_nand_driver = {
+ .probe = axs_nand_probe,
+ .remove = axs_nand_remove,
+ .driver = {
+ .name = "asx-nand",
+ .owner = THIS_MODULE,
+ .of_match_table = axs_nand_dt_ids,
+ },
+};
+
+module_platform_driver(axs_nand_driver);
+
+MODULE_AUTHOR("Alexey Brodkin <abrodkin@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("NAND driver for Synopsys AXS development board");
+MODULE_LICENSE("GPL");
--
1.9.0
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