board/ti/am43xx: add support for parallel NAND

This patch adds support for NAND device connected to GPMC chip-select on
following AM43xx EVM boards.

am437x-gp-evm: On this board, NAND Flash signals are muxed with eMMC, thus at a
  time either eMMC or NAND can be enabled. Selection between eMMC and NAND is
  controlled by:
  (a) Statically using Jumper on connecter (J89) present on board.
  (a) If Jumper on J89 is NOT used, then selection can be dynamically controlled
      by driving SPI2_CS0[MUX_MODE=GPIO] pin via software:
      SPI2_CS0 == 0: NAND (default)
      SPI2_CS0 == 1: eMMC

am43x-epos-evm: On this board, NAND Flash control lines are muxed with QSPI,
  Thus only one of the two can be used at a time. Selection is controlled by:
  (a) Dynamically driving following GPIO pin from software
      GPMC_A0(GPIO) == 0 NAND is selected (default)

NAND device (MT29F4G08AB) on these boards has:
 - data-width=8bits
 - blocksize=256KB
 - pagesize=4KB
 - oobsize=224 bytes
For above NAND device, ROM code expects the boot-loader to be flashed in BCH16
ECC scheme for NAND boot, So by default BCH16 ECC is enabled for AM43xx EVMs.

Signed-off-by: Pekon Gupta <pekon@ti.com>

2 files changed, 43 insertions, 1 deletions

diff --git a/board/ti/am43xx/board.c b/board/ti/am43xx/board.c
index 51fa9e04a3f..a1c3c17fed2 100644
--- a/board/ti/am43xx/board.c
+++ b/board/ti/am43xx/board.c
@@ -626,6 +626,7 @@ int board_init(void)
 	    modena_init0_bw_integer, modena_init0_watermark_0;
 
 	gd->bd->bi_boot_params = CONFIG_SYS_SDRAM_BASE + 0x100;
+	gpmc_init();
 
 	/* Clear all important bits for DSS errata that may need to be tweaked*/
 	mreqprio_0 = readl(&cdev->mreqprio_0) & MREQPRIO_0_SAB_INIT1_MASK &
diff --git a/board/ti/am43xx/mux.c b/board/ti/am43xx/mux.c
index 50967e1a82b..a670b0b2ff4 100644
--- a/board/ti/am43xx/mux.c
+++ b/board/ti/am43xx/mux.c
@@ -73,7 +73,38 @@ static struct module_pin_mux gpio5_7_pin_mux[] = {
 	{-1},
 };
 
-static struct module_pin_mux qspi_pin_mux[] = {
+#ifdef CONFIG_NAND
+static struct module_pin_mux nand_pin_mux[] = {
+	{OFFSET(gpmc_ad0),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD0 */
+	{OFFSET(gpmc_ad1),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD1 */
+	{OFFSET(gpmc_ad2),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD2 */
+	{OFFSET(gpmc_ad3),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD3 */
+	{OFFSET(gpmc_ad4),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD4 */
+	{OFFSET(gpmc_ad5),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD5 */
+	{OFFSET(gpmc_ad6),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD6 */
+	{OFFSET(gpmc_ad7),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD7 */
+#ifdef CONFIG_SYS_NAND_BUSWIDTH_16BIT
+	{OFFSET(gpmc_ad8),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD8  */
+	{OFFSET(gpmc_ad9),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD9  */
+	{OFFSET(gpmc_ad10),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD10 */
+	{OFFSET(gpmc_ad11),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD11 */
+	{OFFSET(gpmc_ad12),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD12 */
+	{OFFSET(gpmc_ad13),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD13 */
+	{OFFSET(gpmc_ad14),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD14 */
+	{OFFSET(gpmc_ad15),	(MODE(0) | PULLUDDIS | RXACTIVE)}, /* AD15 */
+#endif
+	{OFFSET(gpmc_wait0),	(MODE(0) | RXACTIVE | PULLUP_EN)}, /* Wait */
+	{OFFSET(gpmc_wpn),	(MODE(7) | PULLUP_EN)},	/* Write Protect */
+	{OFFSET(gpmc_csn0),	(MODE(0) | PULLUP_EN)},	/* Chip-Select */
+	{OFFSET(gpmc_wen),	(MODE(0) | PULLDOWN_EN)}, /* Write Enable */
+	{OFFSET(gpmc_oen_ren),	(MODE(0) | PULLDOWN_EN)}, /* Read Enable */
+	{OFFSET(gpmc_advn_ale),	(MODE(0) | PULLDOWN_EN)}, /* Addr Latch Enable*/
+	{OFFSET(gpmc_be0n_cle),	(MODE(0) | PULLDOWN_EN)}, /* Byte Enable */
+	{-1},
+};
+#endif
+
+static __maybe_unused struct module_pin_mux qspi_pin_mux[] = {
 	{OFFSET(gpmc_csn0), (MODE(3) | PULLUP_EN | RXACTIVE)}, /* QSPI_CS0 */
 	{OFFSET(gpmc_csn3), (MODE(2) | PULLUP_EN | RXACTIVE)}, /* QSPI_CLK */
 	{OFFSET(gpmc_advn_ale), (MODE(3) | PULLUP_EN | RXACTIVE)}, /* QSPI_D0 */
@@ -97,12 +128,22 @@ void enable_board_pin_mux(void)
 	if (board_is_gpevm()) {
 		configure_module_pin_mux(gpio5_7_pin_mux);
 		configure_module_pin_mux(rgmii1_pin_mux);
+#if defined(CONFIG_NAND)
+		configure_module_pin_mux(nand_pin_mux);
+#endif
 	} else if (board_is_sk()) {
 		configure_module_pin_mux(rgmii1_pin_mux);
+#if defined(CONFIG_NAND)
+		printf("Error: NAND flash not present on this board\n");
+#endif
 		configure_module_pin_mux(qspi_pin_mux);
 	} else if (board_is_eposevm()) {
 		configure_module_pin_mux(rmii1_pin_mux);
+#if defined(CONFIG_NAND)
+		configure_module_pin_mux(nand_pin_mux);
+#else
 		configure_module_pin_mux(qspi_pin_mux);
+#endif
 	}
 }