memory: tegra30-emc: Print additional memory info

Print out memory type and LPDDR2 configuration on Tegra30, making it
similar to the memory info printed by the Tegra20 memory driver. This
info is useful for debugging purposes.

Tested-by: Svyatoslav Ryhel <[e-mail]> # T30 ASUS TF201 LPDDR2
Signed-off-by: Dmitry Osipenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

drivers/memory/tegra/Kconfig

···
 	default y
 	depends on ARCH_TEGRA_3x_SOC || COMPILE_TEST
 	select PM_OPP
+	select DDR
 	help
 	  This driver is for the External Memory Controller (EMC) found on
 	  Tegra30 chips. The EMC controls the external DRAM on the board.

drivers/memory/tegra/tegra30-emc.c

···
  * Copyright (C) 2019 GRATE-DRIVER project
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/clk/tegra.h>
 #include <linux/debugfs.h>
···
 #include <soc/tegra/common.h>
 #include <soc/tegra/fuse.h>
 
+#include "../jedec_ddr.h"
+#include "../of_memory.h"
+
 #include "mc.h"
 
 #define EMC_INTSTATUS				0x000
 #define EMC_INTMASK				0x004
 #define EMC_DBG					0x008
+#define EMC_ADR_CFG				0x010
 #define EMC_CFG					0x00c
 #define EMC_REFCTRL				0x020
 #define EMC_TIMING_CONTROL			0x028
···
 #define EMC_EMRS				0x0d0
 #define EMC_SELF_REF				0x0e0
 #define EMC_MRW					0x0e8
+#define EMC_MRR					0x0ec
 #define EMC_XM2DQSPADCTRL3			0x0f8
 #define EMC_FBIO_SPARE				0x100
 #define EMC_FBIO_CFG5				0x104
···
 
 #define EMC_REFRESH_OVERFLOW_INT		BIT(3)
 #define EMC_CLKCHANGE_COMPLETE_INT		BIT(4)
+#define EMC_MRR_DIVLD_INT			BIT(5)
+
+#define EMC_MRR_DEV_SELECTN			GENMASK(31, 30)
+#define EMC_MRR_MRR_MA				GENMASK(23, 16)
+#define EMC_MRR_MRR_DATA			GENMASK(15, 0)
+
+#define EMC_ADR_CFG_EMEM_NUMDEV			BIT(0)
 
 enum emc_dram_type {
 	DRAM_TYPE_DDR3,
···
 
 	/* protect shared rate-change code path */
 	struct mutex rate_lock;
+
+	bool mrr_error;
 };
 
 static int emc_seq_update_timing(struct tegra_emc *emc)
···
 	return 0;
 }
 
-static struct device_node *emc_find_node_by_ram_code(struct device *dev)
+static struct device_node *emc_find_node_by_ram_code(struct tegra_emc *emc)
 {
+	struct device *dev = emc->dev;
 	struct device_node *np;
 	u32 value, ram_code;
 	int err;
+
+	if (emc->mrr_error) {
+		dev_warn(dev, "memory timings skipped due to MRR error\n");
+		return NULL;
+	}
 
 	if (of_get_child_count(dev->of_node) == 0) {
 		dev_info_once(dev, "device-tree doesn't have memory timings\n");
···
 	return NULL;
 }
 
+static int emc_read_lpddr_mode_register(struct tegra_emc *emc,
+					unsigned int emem_dev,
+					unsigned int register_addr,
+					unsigned int *register_data)
+{
+	u32 memory_dev = emem_dev ? 1 : 2;
+	u32 val, mr_mask = 0xff;
+	int err;
+
+	/* clear data-valid interrupt status */
+	writel_relaxed(EMC_MRR_DIVLD_INT, emc->regs + EMC_INTSTATUS);
+
+	/* issue mode register read request */
+	val  = FIELD_PREP(EMC_MRR_DEV_SELECTN, memory_dev);
+	val |= FIELD_PREP(EMC_MRR_MRR_MA, register_addr);
+
+	writel_relaxed(val, emc->regs + EMC_MRR);
+
+	/* wait for the LPDDR2 data-valid interrupt */
+	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, val,
+						val & EMC_MRR_DIVLD_INT,
+						1, 100);
+	if (err) {
+		dev_err(emc->dev, "mode register %u read failed: %d\n",
+			register_addr, err);
+		emc->mrr_error = true;
+		return err;
+	}
+
+	/* read out mode register data */
+	val = readl_relaxed(emc->regs + EMC_MRR);
+	*register_data = FIELD_GET(EMC_MRR_MRR_DATA, val) & mr_mask;
+
+	return 0;
+}
+
+static void emc_read_lpddr_sdram_info(struct tegra_emc *emc,
+				      unsigned int emem_dev)
+{
+	union lpddr2_basic_config4 basic_conf4;
+	unsigned int manufacturer_id;
+	unsigned int revision_id1;
+	unsigned int revision_id2;
+
+	/* these registers are standard for all LPDDR JEDEC memory chips */
+	emc_read_lpddr_mode_register(emc, emem_dev, 5, &manufacturer_id);
+	emc_read_lpddr_mode_register(emc, emem_dev, 6, &revision_id1);
+	emc_read_lpddr_mode_register(emc, emem_dev, 7, &revision_id2);
+	emc_read_lpddr_mode_register(emc, emem_dev, 8, &basic_conf4.value);
+
+	dev_info(emc->dev, "SDRAM[dev%u]: manufacturer: 0x%x (%s) rev1: 0x%x rev2: 0x%x prefetch: S%u density: %uMbit iowidth: %ubit\n",
+		 emem_dev, manufacturer_id,
+		 lpddr2_jedec_manufacturer(manufacturer_id),
+		 revision_id1, revision_id2,
+		 4 >> basic_conf4.arch_type,
+		 64 << basic_conf4.density,
+		 32 >> basic_conf4.io_width);
+}
+
 static int emc_setup_hw(struct tegra_emc *emc)
 {
+	u32 fbio_cfg5, emc_cfg, emc_dbg, emc_adr_cfg;
 	u32 intmask = EMC_REFRESH_OVERFLOW_INT;
-	u32 fbio_cfg5, emc_cfg, emc_dbg;
+	static bool print_sdram_info_once;
 	enum emc_dram_type dram_type;
+	const char *dram_type_str;
+	unsigned int emem_numdev;
 
 	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
 	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
···
 	emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
 	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
 	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
+
+	switch (dram_type) {
+	case DRAM_TYPE_DDR1:
+		dram_type_str = "DDR1";
+		break;
+	case DRAM_TYPE_LPDDR2:
+		dram_type_str = "LPDDR2";
+		break;
+	case DRAM_TYPE_DDR2:
+		dram_type_str = "DDR2";
+		break;
+	case DRAM_TYPE_DDR3:
+		dram_type_str = "DDR3";
+		break;
+	}
+
+	emc_adr_cfg = readl_relaxed(emc->regs + EMC_ADR_CFG);
+	emem_numdev = FIELD_GET(EMC_ADR_CFG_EMEM_NUMDEV, emc_adr_cfg) + 1;
+
+	dev_info_once(emc->dev, "%u %s %s attached\n", emem_numdev,
+		      dram_type_str, emem_numdev == 2 ? "devices" : "device");
+
+	if (dram_type == DRAM_TYPE_LPDDR2 && !print_sdram_info_once) {
+		while (emem_numdev--)
+			emc_read_lpddr_sdram_info(emc, emem_numdev);
+
+		print_sdram_info_once = true;
+	}
 
 	return 0;
 }
···
 	emc->clk_nb.notifier_call = emc_clk_change_notify;
 	emc->dev = &pdev->dev;
 
-	np = emc_find_node_by_ram_code(&pdev->dev);
-	if (np) {
-		err = emc_load_timings_from_dt(emc, np);
-		of_node_put(np);
-		if (err)
-			return err;
-	}
-
 	emc->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(emc->regs))
 		return PTR_ERR(emc->regs);
···
 	err = emc_setup_hw(emc);
 	if (err)
 		return err;
+
+	np = emc_find_node_by_ram_code(emc);
+	if (np) {
+		err = emc_load_timings_from_dt(emc, np);
+		of_node_put(np);
+		if (err)
+			return err;
+	}
 
 	err = platform_get_irq(pdev, 0);
 	if (err < 0)