nand: lpc32xx: add SLC NAND controller support

The change adds support of LPC32xx SLC NAND controller.

LPC32xx SoC has two different mutually exclusive NAND controllers to
communicate with single and multiple layer chips.

This simple driver allows to specify NAND chip timings and defines
custom read_buf()/write_buf() operations, because access to 8-bit data
register must be 32-bit aligned.

Support of hardware ECC calculation is not implemented (data
correction is always done by software), since it requires a working
DMA engine.

The driver can be included to an SPL image.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Scott Wood <scottwood@freescale.com>
Tested-by: Sylvain Lemieux <slemieux@tycoint.com>

5 files changed, 186 insertions, 0 deletions

diff --git a/arch/arm/cpu/arm926ejs/lpc32xx/devices.c b/arch/arm/cpu/arm926ejs/lpc32xx/devices.c
index 5a453e3..b0287be 100644
--- a/arch/arm/cpu/arm926ejs/lpc32xx/devices.c
+++ b/arch/arm/cpu/arm926ejs/lpc32xx/devices.c
@@ -54,6 +54,12 @@ void lpc32xx_mlc_nand_init(void)
 	writel(CLK_NAND_MLC | CLK_NAND_MLC_INT, &clk->flashclk_ctrl);
 }
 
+void lpc32xx_slc_nand_init(void)
+{
+	/* Enable SLC NAND interface */
+	writel(CLK_NAND_SLC | CLK_NAND_SLC_SELECT, &clk->flashclk_ctrl);
+}
+
 void lpc32xx_i2c_init(unsigned int devnum)
 {
 	/* Enable I2C interface */
diff --git a/arch/arm/include/asm/arch-lpc32xx/clk.h b/arch/arm/include/asm/arch-lpc32xx/clk.h
index 9449869..010211a 100644
--- a/arch/arm/include/asm/arch-lpc32xx/clk.h
+++ b/arch/arm/include/asm/arch-lpc32xx/clk.h
@@ -153,7 +153,9 @@ struct clk_pm_regs {
 #define CLK_DMA_ENABLE			(1 << 0)
 
 /* NAND Clock Control Register bits */
+#define CLK_NAND_SLC			(1 << 0)
 #define CLK_NAND_MLC			(1 << 1)
+#define CLK_NAND_SLC_SELECT		(1 << 2)
 #define CLK_NAND_MLC_INT		(1 << 5)
 
 /* SSP Clock Control Register bits */
diff --git a/arch/arm/include/asm/arch-lpc32xx/sys_proto.h b/arch/arm/include/asm/arch-lpc32xx/sys_proto.h
index c3d890d..0845f83 100644
--- a/arch/arm/include/asm/arch-lpc32xx/sys_proto.h
+++ b/arch/arm/include/asm/arch-lpc32xx/sys_proto.h
@@ -12,6 +12,7 @@
 void lpc32xx_uart_init(unsigned int uart_id);
 void lpc32xx_mac_init(void);
 void lpc32xx_mlc_nand_init(void);
+void lpc32xx_slc_nand_init(void);
 void lpc32xx_i2c_init(unsigned int devnum);
 void lpc32xx_ssp_init(void);
 #if defined(CONFIG_SPL_BUILD)
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index b40dda8..46dce72 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_NAND_KB9202) += kb9202_nand.o
 obj-$(CONFIG_NAND_KIRKWOOD) += kirkwood_nand.o
 obj-$(CONFIG_NAND_KMETER1) += kmeter1_nand.o
 obj-$(CONFIG_NAND_LPC32XX_MLC) += lpc32xx_nand_mlc.o
+obj-$(CONFIG_NAND_LPC32XX_SLC) += lpc32xx_nand_slc.o
 obj-$(CONFIG_NAND_MPC5121_NFC) += mpc5121_nfc.o
 obj-$(CONFIG_NAND_VF610_NFC) += vf610_nfc.o
 obj-$(CONFIG_NAND_MXC) += mxc_nand.o
diff --git a/drivers/mtd/nand/lpc32xx_nand_slc.c b/drivers/mtd/nand/lpc32xx_nand_slc.c
new file mode 100644
index 0000000..719a74d
--- /dev/null
+++ b/drivers/mtd/nand/lpc32xx_nand_slc.c
@@ -0,0 +1,176 @@
+/*
+ * LPC32xx SLC NAND flash controller driver
+ *
+ * (C) Copyright 2015 Vladimir Zapolskiy <vz@mleia.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <nand.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clk.h>
+#include <asm/arch/sys_proto.h>
+
+struct lpc32xx_nand_slc_regs {
+	u32 data;
+	u32 addr;
+	u32 cmd;
+	u32 stop;
+	u32 ctrl;
+	u32 cfg;
+	u32 stat;
+	u32 int_stat;
+	u32 ien;
+	u32 isr;
+	u32 icr;
+	u32 tac;
+	u32 tc;
+	u32 ecc;
+	u32 dma_data;
+};
+
+/* CFG register */
+#define CFG_CE_LOW		(1 << 5)
+
+/* CTRL register */
+#define CTRL_SW_RESET		(1 << 2)
+
+/* STAT register */
+#define STAT_NAND_READY		(1 << 0)
+
+/* INT_STAT register */
+#define INT_STAT_TC		(1 << 1)
+#define INT_STAT_RDY		(1 << 0)
+
+/* TAC register bits, be aware of overflows */
+#define TAC_W_RDY(n)		(max_t(uint32_t, (n), 0xF) << 28)
+#define TAC_W_WIDTH(n)		(max_t(uint32_t, (n), 0xF) << 24)
+#define TAC_W_HOLD(n)		(max_t(uint32_t, (n), 0xF) << 20)
+#define TAC_W_SETUP(n)		(max_t(uint32_t, (n), 0xF) << 16)
+#define TAC_R_RDY(n)		(max_t(uint32_t, (n), 0xF) << 12)
+#define TAC_R_WIDTH(n)		(max_t(uint32_t, (n), 0xF) << 8)
+#define TAC_R_HOLD(n)		(max_t(uint32_t, (n), 0xF) << 4)
+#define TAC_R_SETUP(n)		(max_t(uint32_t, (n), 0xF) << 0)
+
+static struct lpc32xx_nand_slc_regs __iomem *lpc32xx_nand_slc_regs
+	= (struct lpc32xx_nand_slc_regs __iomem *)SLC_NAND_BASE;
+
+static void lpc32xx_nand_init(void)
+{
+	uint32_t hclk = get_hclk_clk_rate();
+
+	/* Reset SLC NAND controller */
+	writel(CTRL_SW_RESET, &lpc32xx_nand_slc_regs->ctrl);
+
+	/* 8-bit bus, no DMA, no ECC, ordinary CE signal */
+	writel(0, &lpc32xx_nand_slc_regs->cfg);
+
+	/* Interrupts disabled and cleared */
+	writel(0, &lpc32xx_nand_slc_regs->ien);
+	writel(INT_STAT_TC | INT_STAT_RDY,
+	       &lpc32xx_nand_slc_regs->icr);
+
+	/* Configure NAND flash timings */
+	writel(TAC_W_RDY(CONFIG_LPC32XX_NAND_SLC_WDR_CLKS) |
+	       TAC_W_WIDTH(hclk / CONFIG_LPC32XX_NAND_SLC_WWIDTH) |
+	       TAC_W_HOLD(hclk / CONFIG_LPC32XX_NAND_SLC_WHOLD) |
+	       TAC_W_SETUP(hclk / CONFIG_LPC32XX_NAND_SLC_WSETUP) |
+	       TAC_R_RDY(CONFIG_LPC32XX_NAND_SLC_RDR_CLKS) |
+	       TAC_R_WIDTH(hclk / CONFIG_LPC32XX_NAND_SLC_RWIDTH) |
+	       TAC_R_HOLD(hclk / CONFIG_LPC32XX_NAND_SLC_RHOLD) |
+	       TAC_R_SETUP(hclk / CONFIG_LPC32XX_NAND_SLC_RSETUP),
+	       &lpc32xx_nand_slc_regs->tac);
+}
+
+static void lpc32xx_nand_cmd_ctrl(struct mtd_info *mtd,
+				  int cmd, unsigned int ctrl)
+{
+	debug("ctrl: 0x%08x, cmd: 0x%08x\n", ctrl, cmd);
+
+	if (ctrl & NAND_NCE)
+		setbits_le32(&lpc32xx_nand_slc_regs->cfg, CFG_CE_LOW);
+	else
+		clrbits_le32(&lpc32xx_nand_slc_regs->cfg, CFG_CE_LOW);
+
+	if (cmd == NAND_CMD_NONE)
+		return;
+
+	if (ctrl & NAND_CLE)
+		writel(cmd & 0xFF, &lpc32xx_nand_slc_regs->cmd);
+	else if (ctrl & NAND_ALE)
+		writel(cmd & 0xFF, &lpc32xx_nand_slc_regs->addr);
+}
+
+static int lpc32xx_nand_dev_ready(struct mtd_info *mtd)
+{
+	return readl(&lpc32xx_nand_slc_regs->stat) & STAT_NAND_READY;
+}
+
+static void lpc32xx_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+	while (len-- > 0)
+		*buf++ = readl(&lpc32xx_nand_slc_regs->data);
+}
+
+static uint8_t lpc32xx_read_byte(struct mtd_info *mtd)
+{
+	return readl(&lpc32xx_nand_slc_regs->data);
+}
+
+static void lpc32xx_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
+{
+	while (len-- > 0)
+		writel(*buf++, &lpc32xx_nand_slc_regs->data);
+}
+
+static void lpc32xx_write_byte(struct mtd_info *mtd, uint8_t byte)
+{
+	writel(byte, &lpc32xx_nand_slc_regs->data);
+}
+
+/*
+ * LPC32xx has only one SLC NAND controller, don't utilize
+ * CONFIG_SYS_NAND_SELF_INIT to be able to reuse this function
+ * both in SPL NAND and U-boot images.
+ */
+int board_nand_init(struct nand_chip *lpc32xx_chip)
+{
+	lpc32xx_chip->cmd_ctrl  = lpc32xx_nand_cmd_ctrl;
+	lpc32xx_chip->dev_ready = lpc32xx_nand_dev_ready;
+
+	/*
+	 * Hardware ECC calculation is not supported by the driver,
+	 * because it requires DMA support, see LPC32x0 User Manual,
+	 * note after SLC_ECC register description (UM10326, p.198)
+	 */
+	lpc32xx_chip->ecc.mode = NAND_ECC_SOFT;
+
+	/*
+	 * The implementation of these functions is quite common, but
+	 * they MUST be defined, because access to data register
+	 * is strictly 32-bit aligned.
+	 */
+	lpc32xx_chip->read_buf   = lpc32xx_read_buf;
+	lpc32xx_chip->read_byte  = lpc32xx_read_byte;
+	lpc32xx_chip->write_buf  = lpc32xx_write_buf;
+	lpc32xx_chip->write_byte = lpc32xx_write_byte;
+
+	/*
+	 * Use default ECC layout, but these values are predefined
+	 * for both small and large page NAND flash devices.
+	 */
+	lpc32xx_chip->ecc.size     = 256;
+	lpc32xx_chip->ecc.bytes    = 3;
+	lpc32xx_chip->ecc.strength = 1;
+
+#if defined(CONFIG_SYS_NAND_USE_FLASH_BBT)
+	lpc32xx_chip->bbt_options |= NAND_BBT_USE_FLASH;
+#endif
+
+	/* Initialize NAND interface */
+	lpc32xx_nand_init();
+
+	return 0;
+}