aspeed: Add basic ast2500-specific drivers and configuration

Clock Driver

This driver is ast2500-specific and is not compatible with earlier
versions of this chip. The differences are not that big, but they are
in somewhat random places, so making it compatible with ast2400 is not
worth the effort at the moment.

SDRAM MC driver

The driver is very ast2500-specific and is completely incompatible
with previous versions of the chip.

The memory controller is very poorly documented by Aspeed in the
datasheet, with any mention of the whole range of registers missing. The
initialization procedure has been basically taken from Aspeed SDK, where
it is implemented in assembly. Here it is rewritten in C, with very limited
understanding of what exactly it is doing.
Reviewed-by: Simon Glass <sjg@chromium.org>

6 files changed, 480 insertions, 0 deletions

diff --git a/arch/arm/mach-aspeed/Kconfig b/arch/arm/mach-aspeed/Kconfig
index b72ed89af7..c5b90bd96a 100644
--- a/arch/arm/mach-aspeed/Kconfig
+++ b/arch/arm/mach-aspeed/Kconfig
@@ -24,4 +24,6 @@ config WDT_NUM
 	  The number of Watchdot Timers on a SoC.
 	  AST2500 has three WDTsk earlier versions have two or fewer.
 
+source "arch/arm/mach-aspeed/ast2500/Kconfig"
+
 endif
diff --git a/arch/arm/mach-aspeed/Makefile b/arch/arm/mach-aspeed/Makefile
index a14b8f751d..1f7af71b03 100644
--- a/arch/arm/mach-aspeed/Makefile
+++ b/arch/arm/mach-aspeed/Makefile
@@ -5,3 +5,4 @@
 #
 
 obj-$(CONFIG_ARCH_ASPEED) += ast_wdt.o
+obj-$(CONFIG_ASPEED_AST2500) += ast2500/
diff --git a/arch/arm/mach-aspeed/ast2500/Kconfig b/arch/arm/mach-aspeed/ast2500/Kconfig
new file mode 100644
index 0000000000..05cb27ea1f
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/Kconfig
@@ -0,0 +1,14 @@
+if ASPEED_AST2500
+
+config SYS_CPU
+	default "arm1176"
+
+config TARGET_EVB_AST2500
+	bool "Evb-AST2500"
+	help
+	  Evb-AST2500 is Aspeed evaluation board for AST2500 chip.
+	  It has 512M of RAM, 32M of SPI flash, two Ethernet ports,
+	  4 Serial ports, 4 USB ports, VGA port, PCIe, SD card slot,
+	  20 pin JTAG, pinouts for 14 I2Cs, 3 SPIs and eSPI, 8 PWMs.
+
+endif
diff --git a/arch/arm/mach-aspeed/ast2500/Makefile b/arch/arm/mach-aspeed/ast2500/Makefile
new file mode 100644
index 0000000000..a35b239ef3
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/Makefile
@@ -0,0 +1 @@
+obj-y += clk_ast2500.o sdram_ast2500.o
diff --git a/arch/arm/mach-aspeed/ast2500/clk_ast2500.c b/arch/arm/mach-aspeed/ast2500/clk_ast2500.c
new file mode 100644
index 0000000000..079909fa64
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/clk_ast2500.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/arch/scu_ast2500.h>
+
+int ast_get_clk(struct udevice **devp)
+{
+	return uclass_get_device_by_driver(UCLASS_CLK,
+			DM_GET_DRIVER(aspeed_ast2500_scu), devp);
+}
+
+void *ast_get_scu(void)
+{
+	struct ast2500_clk_priv *priv;
+	struct udevice *dev;
+	int ret;
+
+	ret = ast_get_clk(&dev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	priv = dev_get_priv(dev);
+
+	return priv->scu;
+}
diff --git a/arch/arm/mach-aspeed/ast2500/sdram_ast2500.c b/arch/arm/mach-aspeed/ast2500/sdram_ast2500.c
new file mode 100644
index 0000000000..ace1028116
--- /dev/null
+++ b/arch/arm/mach-aspeed/ast2500/sdram_ast2500.c
@@ -0,0 +1,432 @@
+/*
+ * Copyright (C) 2012-2020  ASPEED Technology Inc.
+ *
+ * Copyright 2016 Google, Inc
+ *
+ * SPDX-License-Identifier:		GPL-2.0
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <errno.h>
+#include <ram.h>
+#include <regmap.h>
+#include <asm/io.h>
+#include <asm/arch/scu_ast2500.h>
+#include <asm/arch/sdram_ast2500.h>
+#include <asm/arch/wdt.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <dt-bindings/clock/ast2500-scu.h>
+
+/* These configuration parameters are taken from Aspeed SDK */
+#define DDR4_MR46_MODE		0x08000000
+#define DDR4_MR5_MODE		0x400
+#define DDR4_MR13_MODE		0x101
+#define DDR4_MR02_MODE		0x410
+#define DDR4_TRFC		0x45457188
+
+#define PHY_CFG_SIZE		15
+
+static const u32 ddr4_ac_timing[3] = {0x63604e37, 0xe97afa99, 0x00019000};
+static const struct {
+	u32 index[PHY_CFG_SIZE];
+	u32 value[PHY_CFG_SIZE];
+} ddr4_phy_config = {
+	.index = {0, 1, 3, 4, 5, 56, 57, 58, 59, 60, 61, 62, 36, 49, 50},
+	.value = {
+		0x42492aae, 0x09002000, 0x55e00b0b, 0x20000000, 0x24,
+		0x03002900, 0x0e0000a0, 0x000e001c, 0x35b8c106, 0x08080607,
+		0x9b000900, 0x0e400a00, 0x00100008, 0x3c183c3c, 0x00631e0e,
+	},
+};
+
+#define SDRAM_MAX_SIZE		(1024 * 1024 * 1024)
+#define SDRAM_MIN_SIZE		(128 * 1024 * 1024)
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Bandwidth configuration parameters for different SDRAM requests.
+ * These are hardcoded settings taken from Aspeed SDK.
+ */
+static const u32 ddr_max_grant_params[4] = {
+	0x88448844, 0x24422288, 0x22222222, 0x22222222
+};
+
+/*
+ * These registers are not documented by Aspeed at all.
+ * All writes and reads are taken pretty much as is from SDK.
+ */
+struct ast2500_ddr_phy {
+	u32 phy[117];
+};
+
+struct dram_info {
+	struct ram_info info;
+	struct clk ddr_clk;
+	struct ast2500_sdrammc_regs *regs;
+	struct ast2500_scu *scu;
+	struct ast2500_ddr_phy *phy;
+	ulong clock_rate;
+};
+
+static int ast2500_sdrammc_init_phy(struct ast2500_ddr_phy *phy)
+{
+	writel(0, &phy->phy[2]);
+	writel(0, &phy->phy[6]);
+	writel(0, &phy->phy[8]);
+	writel(0, &phy->phy[10]);
+	writel(0, &phy->phy[12]);
+	writel(0, &phy->phy[42]);
+	writel(0, &phy->phy[44]);
+
+	writel(0x86000000, &phy->phy[16]);
+	writel(0x00008600, &phy->phy[17]);
+	writel(0x80000000, &phy->phy[18]);
+	writel(0x80808080, &phy->phy[19]);
+
+	return 0;
+}
+
+static void ast2500_ddr_phy_init_process(struct dram_info *info)
+{
+	struct ast2500_sdrammc_regs *regs = info->regs;
+
+	writel(0, &regs->phy_ctrl[0]);
+	writel(0x4040, &info->phy->phy[51]);
+
+	writel(SDRAM_PHYCTRL0_NRST | SDRAM_PHYCTRL0_INIT, &regs->phy_ctrl[0]);
+	while ((readl(&regs->phy_ctrl[0]) & SDRAM_PHYCTRL0_INIT))
+		;
+	writel(SDRAM_PHYCTRL0_NRST | SDRAM_PHYCTRL0_AUTO_UPDATE,
+	       &regs->phy_ctrl[0]);
+}
+
+static void ast2500_sdrammc_set_vref(struct dram_info *info, u32 vref)
+{
+	writel(0, &info->regs->phy_ctrl[0]);
+	writel((vref << 8) | 0x6, &info->phy->phy[48]);
+	ast2500_ddr_phy_init_process(info);
+}
+
+static int ast2500_ddr_cbr_test(struct dram_info *info)
+{
+	struct ast2500_sdrammc_regs *regs = info->regs;
+	int i;
+	const u32 test_params = SDRAM_TEST_EN
+			| SDRAM_TEST_ERRSTOP
+			| SDRAM_TEST_TWO_MODES;
+	int ret = 0;
+
+	writel((1 << SDRAM_REFRESH_CYCLES_SHIFT) |
+	       (0x5c << SDRAM_REFRESH_PERIOD_SHIFT), &regs->refresh_timing);
+	writel((0xfff << SDRAM_TEST_LEN_SHIFT), &regs->test_addr);
+	writel(0xff00ff00, &regs->test_init_val);
+	writel(SDRAM_TEST_EN | (SDRAM_TEST_MODE_RW << SDRAM_TEST_MODE_SHIFT) |
+	       SDRAM_TEST_ERRSTOP, &regs->ecc_test_ctrl);
+
+	while (!(readl(&regs->ecc_test_ctrl) & SDRAM_TEST_DONE))
+		;
+
+	if (readl(&regs->ecc_test_ctrl) & SDRAM_TEST_FAIL) {
+		ret = -EIO;
+	} else {
+		for (i = 0; i <= SDRAM_TEST_GEN_MODE_MASK; ++i) {
+			writel((i << SDRAM_TEST_GEN_MODE_SHIFT) | test_params,
+			       &regs->ecc_test_ctrl);
+			while (!(readl(&regs->ecc_test_ctrl) & SDRAM_TEST_DONE))
+				;
+			if (readl(&regs->ecc_test_ctrl) & SDRAM_TEST_FAIL) {
+				ret = -EIO;
+				break;
+			}
+		}
+	}
+
+	writel(0, &regs->refresh_timing);
+	writel(0, &regs->ecc_test_ctrl);
+
+	return ret;
+}
+
+static int ast2500_sdrammc_ddr4_calibrate_vref(struct dram_info *info)
+{
+	int i;
+	int vref_min = 0xff;
+	int vref_max = 0;
+	int range_size = 0;
+
+	for (i = 1; i < 0x40; ++i) {
+		int res;
+
+		ast2500_sdrammc_set_vref(info, i);
+		res = ast2500_ddr_cbr_test(info);
+		if (res < 0) {
+			if (range_size > 0)
+				break;
+		} else {
+			++range_size;
+			vref_min = min(vref_min, i);
+			vref_max = max(vref_max, i);
+		}
+	}
+
+	/* Pick average setting */
+	ast2500_sdrammc_set_vref(info, (vref_min + vref_max + 1) / 2);
+
+	return 0;
+}
+
+static size_t ast2500_sdrammc_get_vga_mem_size(struct dram_info *info)
+{
+	size_t vga_mem_size_base = 8 * 1024 * 1024;
+	u32 vga_hwconf = (readl(&info->scu->hwstrap)
+			  >> SCU_HWSTRAP_VGAMEM_SHIFT)
+			& SCU_HWSTRAP_VGAMEM_MASK;
+
+	return vga_mem_size_base << vga_hwconf;
+}
+
+/*
+ * Find out RAM size and save it in dram_info
+ *
+ * The procedure is taken from Aspeed SDK
+ */
+static void ast2500_sdrammc_calc_size(struct dram_info *info)
+{
+	/* The controller supports 128/256/512/1024 MB ram */
+	size_t ram_size = SDRAM_MIN_SIZE;
+	const int write_test_offset = 0x100000;
+	u32 test_pattern = 0xdeadbeef;
+	u32 cap_param = SDRAM_CONF_CAP_1024M;
+	u32 refresh_timing_param = DDR4_TRFC;
+	const u32 write_addr_base = CONFIG_SYS_SDRAM_BASE + write_test_offset;
+
+	for (ram_size = SDRAM_MAX_SIZE; ram_size > SDRAM_MIN_SIZE;
+	     ram_size >>= 1) {
+		writel(test_pattern, write_addr_base + (ram_size >> 1));
+		test_pattern = (test_pattern >> 4) | (test_pattern << 28);
+	}
+
+	/* One last write to overwrite all wrapped values */
+	writel(test_pattern, write_addr_base);
+
+	/* Reset the pattern and see which value was really written */
+	test_pattern = 0xdeadbeef;
+	for (ram_size = SDRAM_MAX_SIZE; ram_size > SDRAM_MIN_SIZE;
+	     ram_size >>= 1) {
+		if (readl(write_addr_base + (ram_size >> 1)) == test_pattern)
+			break;
+
+		--cap_param;
+		refresh_timing_param >>= 8;
+		test_pattern = (test_pattern >> 4) | (test_pattern << 28);
+	}
+
+	clrsetbits_le32(&info->regs->ac_timing[1],
+			(SDRAM_AC_TRFC_MASK << SDRAM_AC_TRFC_SHIFT),
+			((refresh_timing_param & SDRAM_AC_TRFC_MASK)
+			 << SDRAM_AC_TRFC_SHIFT));
+
+	info->info.base = CONFIG_SYS_SDRAM_BASE;
+	info->info.size = ram_size - ast2500_sdrammc_get_vga_mem_size(info);
+	clrsetbits_le32(&info->regs->config,
+			(SDRAM_CONF_CAP_MASK << SDRAM_CONF_CAP_SHIFT),
+			((cap_param & SDRAM_CONF_CAP_MASK)
+			 << SDRAM_CONF_CAP_SHIFT));
+}
+
+static int ast2500_sdrammc_init_ddr4(struct dram_info *info)
+{
+	int i;
+	const u32 power_control = SDRAM_PCR_CKE_EN
+	    | (1 << SDRAM_PCR_CKE_DELAY_SHIFT)
+	    | (2 << SDRAM_PCR_TCKE_PW_SHIFT)
+	    | SDRAM_PCR_RESETN_DIS
+	    | SDRAM_PCR_RGAP_CTRL_EN | SDRAM_PCR_ODT_EN | SDRAM_PCR_ODT_EXT_EN;
+	const u32 conf = (SDRAM_CONF_CAP_1024M << SDRAM_CONF_CAP_SHIFT)
+#ifdef CONFIG_DUALX8_RAM
+	    | SDRAM_CONF_DUALX8
+#endif
+	    | SDRAM_CONF_SCRAMBLE | SDRAM_CONF_SCRAMBLE_PAT2 | SDRAM_CONF_DDR4;
+	int ret;
+
+	writel(conf, &info->regs->config);
+	for (i = 0; i < ARRAY_SIZE(ddr4_ac_timing); ++i)
+		writel(ddr4_ac_timing[i], &info->regs->ac_timing[i]);
+
+	writel(DDR4_MR46_MODE, &info->regs->mr46_mode_setting);
+	writel(DDR4_MR5_MODE, &info->regs->mr5_mode_setting);
+	writel(DDR4_MR02_MODE, &info->regs->mr02_mode_setting);
+	writel(DDR4_MR13_MODE, &info->regs->mr13_mode_setting);
+
+	for (i = 0; i < PHY_CFG_SIZE; ++i) {
+		writel(ddr4_phy_config.value[i],
+		       &info->phy->phy[ddr4_phy_config.index[i]]);
+	}
+
+	writel(power_control, &info->regs->power_control);
+
+	ast2500_ddr_phy_init_process(info);
+
+	ret = ast2500_sdrammc_ddr4_calibrate_vref(info);
+	if (ret < 0) {
+		debug("Vref calibration failed!\n");
+		return ret;
+	}
+
+	writel((1 << SDRAM_REFRESH_CYCLES_SHIFT)
+	       | SDRAM_REFRESH_ZQCS_EN | (0x2f << SDRAM_REFRESH_PERIOD_SHIFT),
+	       &info->regs->refresh_timing);
+
+	setbits_le32(&info->regs->power_control,
+		     SDRAM_PCR_AUTOPWRDN_EN | SDRAM_PCR_ODT_AUTO_ON);
+
+	ast2500_sdrammc_calc_size(info);
+
+	setbits_le32(&info->regs->config, SDRAM_CONF_CACHE_INIT_EN);
+	while (!(readl(&info->regs->config) & SDRAM_CONF_CACHE_INIT_DONE))
+		;
+	setbits_le32(&info->regs->config, SDRAM_CONF_CACHE_EN);
+
+	writel(SDRAM_MISC_DDR4_TREFRESH, &info->regs->misc_control);
+
+	/* Enable all requests except video & display */
+	writel(SDRAM_REQ_USB20_EHCI1
+	       | SDRAM_REQ_USB20_EHCI2
+	       | SDRAM_REQ_CPU
+	       | SDRAM_REQ_AHB2
+	       | SDRAM_REQ_AHB
+	       | SDRAM_REQ_MAC0
+	       | SDRAM_REQ_MAC1
+	       | SDRAM_REQ_PCIE
+	       | SDRAM_REQ_XDMA
+	       | SDRAM_REQ_ENCRYPTION
+	       | SDRAM_REQ_VIDEO_FLAG
+	       | SDRAM_REQ_VIDEO_LOW_PRI_WRITE
+	       | SDRAM_REQ_2D_RW
+	       | SDRAM_REQ_MEMCHECK, &info->regs->req_limit_mask);
+
+	return 0;
+}
+
+static void ast2500_sdrammc_unlock(struct dram_info *info)
+{
+	writel(SDRAM_UNLOCK_KEY, &info->regs->protection_key);
+	while (!readl(&info->regs->protection_key))
+		;
+}
+
+static void ast2500_sdrammc_lock(struct dram_info *info)
+{
+	writel(~SDRAM_UNLOCK_KEY, &info->regs->protection_key);
+	while (readl(&info->regs->protection_key))
+		;
+}
+
+static int ast2500_sdrammc_probe(struct udevice *dev)
+{
+	struct dram_info *priv = (struct dram_info *)dev_get_priv(dev);
+	struct ast2500_sdrammc_regs *regs = priv->regs;
+	int i;
+	int ret = clk_get_by_index(dev, 0, &priv->ddr_clk);
+
+	if (ret) {
+		debug("DDR:No CLK\n");
+		return ret;
+	}
+
+	priv->scu = ast_get_scu();
+	if (IS_ERR(priv->scu)) {
+		debug("%s(): can't get SCU\n", __func__);
+		return PTR_ERR(priv->scu);
+	}
+
+	clk_set_rate(&priv->ddr_clk, priv->clock_rate);
+	ret = ast_wdt_reset_masked(ast_get_wdt(0), WDT_RESET_SDRAM);
+	if (ret) {
+		debug("%s(): SDRAM reset failed\n", __func__);
+		return ret;
+	}
+
+	ast2500_sdrammc_unlock(priv);
+
+	writel(SDRAM_PCR_MREQI_DIS | SDRAM_PCR_RESETN_DIS,
+	       &regs->power_control);
+	writel(SDRAM_VIDEO_UNLOCK_KEY, &regs->gm_protection_key);
+
+	/* Mask all requests except CPU and AHB during PHY init */
+	writel(~(SDRAM_REQ_CPU | SDRAM_REQ_AHB), &regs->req_limit_mask);
+
+	for (i = 0; i < ARRAY_SIZE(ddr_max_grant_params); ++i)
+		writel(ddr_max_grant_params[i], &regs->max_grant_len[i]);
+
+	setbits_le32(&regs->intr_ctrl, SDRAM_ICR_RESET_ALL);
+
+	ast2500_sdrammc_init_phy(priv->phy);
+	if (readl(&priv->scu->hwstrap) & SCU_HWSTRAP_DDR4) {
+		ast2500_sdrammc_init_ddr4(priv);
+	} else {
+		debug("Unsupported DRAM3\n");
+		return -EINVAL;
+	}
+
+	clrbits_le32(&regs->intr_ctrl, SDRAM_ICR_RESET_ALL);
+	ast2500_sdrammc_lock(priv);
+
+	return 0;
+}
+
+static int ast2500_sdrammc_ofdata_to_platdata(struct udevice *dev)
+{
+	struct dram_info *priv = dev_get_priv(dev);
+	struct regmap *map;
+	int ret;
+
+	ret = regmap_init_mem(dev, &map);
+	if (ret)
+		return ret;
+
+	priv->regs = regmap_get_range(map, 0);
+	priv->phy = regmap_get_range(map, 1);
+
+	priv->clock_rate = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+					  "clock-frequency", 0);
+
+	if (!priv->clock_rate) {
+		debug("DDR Clock Rate not defined\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ast2500_sdrammc_get_info(struct udevice *dev, struct ram_info *info)
+{
+	struct dram_info *priv = dev_get_priv(dev);
+
+	*info = priv->info;
+
+	return 0;
+}
+
+static struct ram_ops ast2500_sdrammc_ops = {
+	.get_info = ast2500_sdrammc_get_info,
+};
+
+static const struct udevice_id ast2500_sdrammc_ids[] = {
+	{ .compatible = "aspeed,ast2500-sdrammc" },
+	{ }
+};
+
+U_BOOT_DRIVER(sdrammc_ast2500) = {
+	.name = "aspeed_ast2500_sdrammc",
+	.id = UCLASS_RAM,
+	.of_match = ast2500_sdrammc_ids,
+	.ops = &ast2500_sdrammc_ops,
+	.ofdata_to_platdata = ast2500_sdrammc_ofdata_to_platdata,
+	.probe = ast2500_sdrammc_probe,
+	.priv_auto_alloc_size = sizeof(struct dram_info),
+};