ram: add SDRAM driver for i.MXRT SoCs

Add SDRAM driver for i.MXRT SoCs.

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>

3 files changed, 449 insertions, 0 deletions

diff --git a/drivers/ram/Kconfig b/drivers/ram/Kconfig
index b454ceb599..56fea7c94c 100644
--- a/drivers/ram/Kconfig
+++ b/drivers/ram/Kconfig
@@ -65,5 +65,13 @@ config K3_J721E_DDRSS
 	  Enabling this config adds support for the DDR memory controller
 	  on J721E family of SoCs.
 
+config IMXRT_SDRAM
+	bool "Enable i.MXRT SDRAM support"
+	depends on RAM
+	help
+	  i.MXRT family devices support smart external memory controller(SEMC)
+	  to support external memories like sdram, psram & nand.
+	  This driver is for the sdram memory interface with the SEMC.
+
 source "drivers/ram/rockchip/Kconfig"
 source "drivers/ram/stm32mp1/Kconfig"
diff --git a/drivers/ram/Makefile b/drivers/ram/Makefile
index 4b77969b39..5c897410c6 100644
--- a/drivers/ram/Makefile
+++ b/drivers/ram/Makefile
@@ -15,3 +15,5 @@ obj-$(CONFIG_ARCH_ROCKCHIP) += rockchip/
 obj-$(CONFIG_K3_AM654_DDRSS) += k3-am654-ddrss.o
 obj-$(CONFIG_ARCH_MEDIATEK) += mediatek/
 obj-$(CONFIG_K3_J721E_DDRSS) += k3-j721e/
+
+obj-$(CONFIG_IMXRT_SDRAM) += imxrt_sdram.o
diff --git a/drivers/ram/imxrt_sdram.c b/drivers/ram/imxrt_sdram.c
new file mode 100644
index 0000000000..af7400be82
--- /dev/null
+++ b/drivers/ram/imxrt_sdram.c
@@ -0,0 +1,439 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019
+ * Author(s): Giulio Benetti <giulio.benetti@benettiengineering.com>
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <ram.h>
+#include <asm/io.h>
+
+/* SDRAM Command Code */
+#define SD_CC_ARD		0x0     /* Master Bus (AXI) command - Read */
+#define SD_CC_AWR		0x1     /* Master Bus (AXI) command - Write */
+#define SD_CC_IRD		0x8     /* IP command - Read */
+#define SD_CC_IWR		0x9     /* IP command - Write */
+#define SD_CC_IMS		0xA     /* IP command - Set Mode Register */
+#define SD_CC_IACT		0xB     /* IP command - ACTIVE */
+#define SD_CC_IAF		0xC     /* IP command - Auto Refresh */
+#define SD_CC_ISF		0xD     /* IP Command - Self Refresh */
+#define SD_CC_IPRE		0xE     /* IP command - Precharge */
+#define SD_CC_IPREA		0xF     /* IP command - Precharge ALL */
+
+#define SEMC_MCR_MDIS		BIT(1)
+#define SEMC_MCR_DQSMD		BIT(2)
+
+#define SEMC_INTR_IPCMDERR	BIT(1)
+#define SEMC_INTR_IPCMDDONE	BIT(0)
+
+#define SEMC_IPCMD_KEY		0xA55A0000
+
+struct imxrt_semc_regs {
+	/* 0x0 */
+	u32 mcr;
+	u32 iocr;
+	u32 bmcr0;
+	u32 bmcr1;
+	u32 br[9];
+
+	/* 0x34 */
+	u32 res1;
+	u32 inten;
+	u32 intr;
+	/* 0x40 */
+	u32 sdramcr0;
+	u32 sdramcr1;
+	u32 sdramcr2;
+	u32 sdramcr3;
+	/* 0x50 */
+	u32 nandcr0;
+	u32 nandcr1;
+	u32 nandcr2;
+	u32 nandcr3;
+	/* 0x60 */
+	u32 norcr0;
+	u32 norcr1;
+	u32 norcr2;
+	u32 norcr3;
+	/* 0x70 */
+	u32 sramcr0;
+	u32 sramcr1;
+	u32 sramcr2;
+	u32 sramcr3;
+	/* 0x80 */
+	u32 dbicr0;
+	u32 dbicr1;
+	u32 res2[2];
+	/* 0x90 */
+	u32 ipcr0;
+	u32 ipcr1;
+	u32 ipcr2;
+	u32 ipcmd;
+	/* 0xA0 */
+	u32 iptxdat;
+	u32 res3[3];
+	/* 0xB0 */
+	u32 iprxdat;
+	u32 res4[3];
+	/* 0xC0 */
+	u32 sts[16];
+};
+
+#define SEMC_IOCR_MUX_A8_SHIFT		0
+#define SEMC_IOCR_MUX_CSX0_SHIFT	3
+#define SEMC_IOCR_MUX_CSX1_SHIFT	6
+#define SEMC_IOCR_MUX_CSX2_SHIFT	9
+#define SEMC_IOCR_MUX_CSX3_SHIFT	12
+#define SEMC_IOCR_MUX_RDY_SHIFT		15
+
+struct imxrt_sdram_mux {
+	u8 a8;
+	u8 csx0;
+	u8 csx1;
+	u8 csx2;
+	u8 csx3;
+	u8 rdy;
+};
+
+#define SEMC_SDRAMCR0_PS_SHIFT		0
+#define SEMC_SDRAMCR0_BL_SHIFT		4
+#define SEMC_SDRAMCR0_COL_SHIFT		8
+#define SEMC_SDRAMCR0_CL_SHIFT		10
+
+struct imxrt_sdram_control {
+	u8 memory_width;
+	u8 burst_len;
+	u8 no_columns;
+	u8 cas_latency;
+};
+
+#define SEMC_SDRAMCR1_PRE2ACT_SHIFT	0
+#define SEMC_SDRAMCR1_ACT2RW_SHIFT	4
+#define SEMC_SDRAMCR1_RFRC_SHIFT	8
+#define SEMC_SDRAMCR1_WRC_SHIFT		13
+#define SEMC_SDRAMCR1_CKEOFF_SHIFT	16
+#define SEMC_SDRAMCR1_ACT2PRE_SHIFT	20
+
+#define SEMC_SDRAMCR2_SRRC_SHIFT	0
+#define SEMC_SDRAMCR2_REF2REF_SHIFT	8
+#define SEMC_SDRAMCR2_ACT2ACT_SHIFT	16
+#define SEMC_SDRAMCR2_ITO_SHIFT		24
+
+#define SEMC_SDRAMCR3_REN		BIT(0)
+#define SEMC_SDRAMCR3_REBL_SHIFT	1
+#define SEMC_SDRAMCR3_PRESCALE_SHIFT	8
+#define SEMC_SDRAMCR3_RT_SHIFT		16
+#define SEMC_SDRAMCR3_UT_SHIFT		24
+
+struct imxrt_sdram_timing {
+	u8 pre2act;
+	u8 act2rw;
+	u8 rfrc;
+	u8 wrc;
+	u8 ckeoff;
+	u8 act2pre;
+
+	u8 srrc;
+	u8 ref2ref;
+	u8 act2act;
+	u8 ito;
+
+	u8 rebl;
+	u8 prescale;
+	u8 rt;
+	u8 ut;
+};
+
+enum imxrt_semc_bank {
+	SDRAM_BANK1,
+	SDRAM_BANK2,
+	SDRAM_BANK3,
+	SDRAM_BANK4,
+	MAX_SDRAM_BANK,
+};
+
+#define SEMC_BR_VLD_MASK		1
+#define SEMC_BR_MS_SHIFT		1
+
+struct bank_params {
+	enum imxrt_semc_bank target_bank;
+	u32 base_address;
+	u32 memory_size;
+};
+
+struct imxrt_sdram_params {
+	struct imxrt_semc_regs *base;
+
+	struct imxrt_sdram_mux *sdram_mux;
+	struct imxrt_sdram_control *sdram_control;
+	struct imxrt_sdram_timing *sdram_timing;
+
+	struct bank_params bank_params[MAX_SDRAM_BANK];
+	u8 no_sdram_banks;
+};
+
+static int imxrt_sdram_wait_ipcmd_done(struct imxrt_semc_regs *regs)
+{
+	do {
+		readl(&regs->intr);
+
+		if (regs->intr & SEMC_INTR_IPCMDDONE)
+			return 0;
+		if (regs->intr & SEMC_INTR_IPCMDERR)
+			return -EIO;
+
+		mdelay(50);
+	} while (1);
+}
+
+static int imxrt_sdram_ipcmd(struct imxrt_semc_regs *regs, u32 mem_addr,
+			     u32 ipcmd, u32 wd, u32 *rd)
+{
+	int ret;
+
+	if (ipcmd == SD_CC_IWR || ipcmd == SD_CC_IMS)
+		writel(wd, &regs->iptxdat);
+
+	/* set slave address for every command as specified on RM */
+	writel(mem_addr, &regs->ipcr0);
+
+	/* execute command */
+	writel(SEMC_IPCMD_KEY | ipcmd, &regs->ipcmd);
+
+	ret = imxrt_sdram_wait_ipcmd_done(regs);
+	if (ret < 0)
+		return ret;
+
+	if (ipcmd == SD_CC_IRD) {
+		if (!rd)
+			return -EINVAL;
+
+		*rd = readl(&regs->iprxdat);
+	}
+
+	return 0;
+}
+
+int imxrt_sdram_init(struct udevice *dev)
+{
+	struct imxrt_sdram_params *params = dev_get_platdata(dev);
+	struct imxrt_sdram_mux *mux = params->sdram_mux;
+	struct imxrt_sdram_control *ctrl = params->sdram_control;
+	struct imxrt_sdram_timing *time = params->sdram_timing;
+	struct imxrt_semc_regs *regs = params->base;
+	struct bank_params *bank_params;
+	u32 rd;
+	int i;
+
+	/* enable the SEMC controller */
+	clrbits_le32(&regs->mcr, SEMC_MCR_MDIS);
+	/* set DQS mode from DQS pad */
+	setbits_le32(&regs->mcr, SEMC_MCR_DQSMD);
+
+	for (i = 0, bank_params = params->bank_params;
+		i < params->no_sdram_banks; bank_params++,
+		i++)
+		writel((bank_params->base_address & 0xfffff000)
+		       | bank_params->memory_size << SEMC_BR_MS_SHIFT
+		       | SEMC_BR_VLD_MASK,
+		       &regs->br[bank_params->target_bank]);
+
+	writel(mux->a8 << SEMC_IOCR_MUX_A8_SHIFT
+		| mux->csx0 << SEMC_IOCR_MUX_CSX0_SHIFT
+		| mux->csx1 << SEMC_IOCR_MUX_CSX1_SHIFT
+		| mux->csx2 << SEMC_IOCR_MUX_CSX2_SHIFT
+		| mux->csx3 << SEMC_IOCR_MUX_CSX3_SHIFT
+		| mux->rdy << SEMC_IOCR_MUX_RDY_SHIFT,
+		&regs->iocr);
+
+	writel(ctrl->memory_width << SEMC_SDRAMCR0_PS_SHIFT
+		| ctrl->burst_len << SEMC_SDRAMCR0_BL_SHIFT
+		| ctrl->no_columns << SEMC_SDRAMCR0_COL_SHIFT
+		| ctrl->cas_latency << SEMC_SDRAMCR0_CL_SHIFT,
+		&regs->sdramcr0);
+
+	writel(time->pre2act << SEMC_SDRAMCR1_PRE2ACT_SHIFT
+		| time->act2rw << SEMC_SDRAMCR1_ACT2RW_SHIFT
+		| time->rfrc << SEMC_SDRAMCR1_RFRC_SHIFT
+		| time->wrc << SEMC_SDRAMCR1_WRC_SHIFT
+		| time->ckeoff << SEMC_SDRAMCR1_CKEOFF_SHIFT
+		| time->act2pre << SEMC_SDRAMCR1_ACT2PRE_SHIFT,
+		&regs->sdramcr1);
+
+	writel(time->srrc << SEMC_SDRAMCR2_SRRC_SHIFT
+		| time->ref2ref << SEMC_SDRAMCR2_REF2REF_SHIFT
+		| time->act2act << SEMC_SDRAMCR2_ACT2ACT_SHIFT
+		| time->ito << SEMC_SDRAMCR2_ITO_SHIFT,
+		&regs->sdramcr2);
+
+	writel(time->rebl << SEMC_SDRAMCR3_REBL_SHIFT
+		| time->prescale << SEMC_SDRAMCR3_PRESCALE_SHIFT
+		| time->rt << SEMC_SDRAMCR3_RT_SHIFT
+		| time->ut << SEMC_SDRAMCR3_UT_SHIFT
+		| SEMC_SDRAMCR3_REN,
+		&regs->sdramcr3);
+
+	writel(2, &regs->ipcr1);
+
+	for (i = 0, bank_params = params->bank_params;
+		i < params->no_sdram_banks; bank_params++,
+		i++) {
+		mdelay(250);
+		imxrt_sdram_ipcmd(regs, bank_params->base_address, SD_CC_IPREA,
+				  0, &rd);
+		imxrt_sdram_ipcmd(regs, bank_params->base_address, SD_CC_IAF,
+				  0, &rd);
+		imxrt_sdram_ipcmd(regs, bank_params->base_address, SD_CC_IAF,
+				  0, &rd);
+		imxrt_sdram_ipcmd(regs, bank_params->base_address, SD_CC_IMS,
+				  ctrl->burst_len | (ctrl->cas_latency << 4),
+				  &rd);
+		mdelay(250);
+	}
+
+	return 0;
+}
+
+static int imxrt_semc_ofdata_to_platdata(struct udevice *dev)
+{
+	struct imxrt_sdram_params *params = dev_get_platdata(dev);
+	ofnode bank_node;
+	u8 bank = 0;
+
+	params->sdram_mux =
+		(struct imxrt_sdram_mux *)
+		 dev_read_u8_array_ptr(dev,
+				       "fsl,sdram-mux",
+				       sizeof(struct imxrt_sdram_mux));
+	if (!params->sdram_mux) {
+		pr_err("fsl,sdram-mux not found");
+		return -EINVAL;
+	}
+
+	params->sdram_control =
+		(struct imxrt_sdram_control *)
+		 dev_read_u8_array_ptr(dev,
+				       "fsl,sdram-control",
+				       sizeof(struct imxrt_sdram_control));
+	if (!params->sdram_control) {
+		pr_err("fsl,sdram-control not found");
+		return -EINVAL;
+	}
+
+	params->sdram_timing =
+		(struct imxrt_sdram_timing *)
+		 dev_read_u8_array_ptr(dev,
+				       "fsl,sdram-timing",
+				       sizeof(struct imxrt_sdram_timing));
+	if (!params->sdram_timing) {
+		pr_err("fsl,sdram-timing not found");
+		return -EINVAL;
+	}
+
+	dev_for_each_subnode(bank_node, dev) {
+		struct bank_params *bank_params;
+		char *bank_name;
+		int ret;
+
+		/* extract the bank index from DT */
+		bank_name = (char *)ofnode_get_name(bank_node);
+		strsep(&bank_name, "@");
+		if (!bank_name) {
+			pr_err("missing sdram bank index");
+			return -EINVAL;
+		}
+
+		bank_params = &params->bank_params[bank];
+		strict_strtoul(bank_name, 10,
+			       (unsigned long *)&bank_params->target_bank);
+		if (bank_params->target_bank >= MAX_SDRAM_BANK) {
+			pr_err("Found bank %d , but only bank 0,1,2,3 are supported",
+			       bank_params->target_bank);
+			return -EINVAL;
+		}
+
+		ret = ofnode_read_u32(bank_node,
+				      "fsl,memory-size",
+				      &bank_params->memory_size);
+		if (ret < 0) {
+			pr_err("fsl,memory-size not found");
+			return -EINVAL;
+		}
+
+		ret = ofnode_read_u32(bank_node,
+				      "fsl,base-address",
+				      &bank_params->base_address);
+		if (ret < 0) {
+			pr_err("fsl,base-address not found");
+			return -EINVAL;
+		}
+
+		debug("Found bank %s %u\n", bank_name,
+		      bank_params->target_bank);
+		bank++;
+	}
+
+	params->no_sdram_banks = bank;
+	debug("%s, no of banks = %d\n", __func__, params->no_sdram_banks);
+
+	return 0;
+}
+
+static int imxrt_semc_probe(struct udevice *dev)
+{
+	struct imxrt_sdram_params *params = dev_get_platdata(dev);
+	int ret;
+	fdt_addr_t addr;
+
+	addr = dev_read_addr(dev);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	params->base = (struct imxrt_semc_regs *)addr;
+
+#ifdef CONFIG_CLK
+	struct clk clk;
+
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&clk);
+
+	if (ret) {
+		dev_err(dev, "failed to enable clock\n");
+		return ret;
+	}
+#endif
+	ret = imxrt_sdram_init(dev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int imxrt_semc_get_info(struct udevice *dev, struct ram_info *info)
+{
+	return 0;
+}
+
+static struct ram_ops imxrt_semc_ops = {
+	.get_info = imxrt_semc_get_info,
+};
+
+static const struct udevice_id imxrt_semc_ids[] = {
+	{ .compatible = "fsl,imxrt-semc", .data = 0 },
+	{ }
+};
+
+U_BOOT_DRIVER(imxrt_semc) = {
+	.name = "imxrt_semc",
+	.id = UCLASS_RAM,
+	.of_match = imxrt_semc_ids,
+	.ops = &imxrt_semc_ops,
+	.ofdata_to_platdata = imxrt_semc_ofdata_to_platdata,
+	.probe = imxrt_semc_probe,
+	.platdata_auto_alloc_size = sizeof(struct imxrt_sdram_params),
+};