EDAC, mellanox: Add ECC support for BlueField DDR4

Add ECC support for Mellanox BlueField SoC DDR controller.
This requires SMC to the running Arm Trusted Firmware to report
what is the current memory configuration.

Reviewed-by: James Morse <[e-mail]>
Signed-off-by: Shravan Kumar Ramani <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

MAINTAINERS

···
 F:	drivers/edac/aspeed_edac.c
 F:	Documentation/devicetree/bindings/edac/aspeed-sdram-edac.txt
 
+EDAC-BLUEFIELD
+M:	Shravan Kumar Ramani <[e-mail]>
+S:	Supported
+F:	drivers/edac/bluefield_edac.c
+
 EDAC-CALXEDA
 M:	Robert Richter <[e-mail]>
 L:	[e-mail]

drivers/edac/Kconfig

···
 	  First, ECC must be configured in the bootloader. Then, this driver
 	  will expose error counters via the EDAC kernel framework.
 
+config EDAC_BLUEFIELD
+	tristate "Mellanox BlueField Memory ECC"
+	depends on ARM64 && ((MELLANOX_PLATFORM && ACPI) || COMPILE_TEST)
+	help
+	  Support for error detection and correction on the
+	  Mellanox BlueField SoCs.
+
 endif # EDAC

drivers/edac/Makefile

···
 obj-$(CONFIG_EDAC_TI)			+= ti_edac.o
 obj-$(CONFIG_EDAC_QCOM)			+= qcom_edac.o
 obj-$(CONFIG_EDAC_ASPEED)		+= aspeed_edac.o
+obj-$(CONFIG_EDAC_BLUEFIELD)		+= bluefield_edac.o

drivers/edac/bluefield_edac.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Bluefield-specific EDAC driver.
+ *
+ * Copyright (c) 2019 Mellanox Technologies.
+ */
+
+#include <linux/acpi.h>
+#include <linux/arm-smccc.h>
+#include <linux/bitfield.h>
+#include <linux/edac.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "edac_module.h"
+
+#define DRIVER_NAME		"bluefield-edac"
+
+/*
+ * Mellanox BlueField EMI (External Memory Interface) register definitions.
+ */
+
+#define MLXBF_ECC_CNT 0x340
+#define MLXBF_ECC_CNT__SERR_CNT GENMASK(15, 0)
+#define MLXBF_ECC_CNT__DERR_CNT GENMASK(31, 16)
+
+#define MLXBF_ECC_ERR 0x348
+#define MLXBF_ECC_ERR__SECC BIT(0)
+#define MLXBF_ECC_ERR__DECC BIT(16)
+
+#define MLXBF_ECC_LATCH_SEL 0x354
+#define MLXBF_ECC_LATCH_SEL__START BIT(24)
+
+#define MLXBF_ERR_ADDR_0 0x358
+
+#define MLXBF_ERR_ADDR_1 0x37c
+
+#define MLXBF_SYNDROM 0x35c
+#define MLXBF_SYNDROM__DERR BIT(0)
+#define MLXBF_SYNDROM__SERR BIT(1)
+#define MLXBF_SYNDROM__SYN GENMASK(25, 16)
+
+#define MLXBF_ADD_INFO 0x364
+#define MLXBF_ADD_INFO__ERR_PRANK GENMASK(9, 8)
+
+#define MLXBF_EDAC_MAX_DIMM_PER_MC	2
+#define MLXBF_EDAC_ERROR_GRAIN		8
+
+/*
+ * Request MLNX_SIP_GET_DIMM_INFO
+ *
+ * Retrieve information about DIMM on a certain slot.
+ *
+ * Call register usage:
+ * a0: MLNX_SIP_GET_DIMM_INFO
+ * a1: (Memory controller index) << 16 | (Dimm index in memory controller)
+ * a2-7: not used.
+ *
+ * Return status:
+ * a0: MLXBF_DIMM_INFO defined below describing the DIMM.
+ * a1-3: not used.
+ */
+#define MLNX_SIP_GET_DIMM_INFO		0x82000008
+
+/* Format for the SMC response about the memory information */
+#define MLXBF_DIMM_INFO__SIZE_GB GENMASK_ULL(15, 0)
+#define MLXBF_DIMM_INFO__IS_RDIMM BIT(16)
+#define MLXBF_DIMM_INFO__IS_LRDIMM BIT(17)
+#define MLXBF_DIMM_INFO__IS_NVDIMM BIT(18)
+#define MLXBF_DIMM_INFO__RANKS GENMASK_ULL(23, 21)
+#define MLXBF_DIMM_INFO__PACKAGE_X GENMASK_ULL(31, 24)
+
+struct bluefield_edac_priv {
+	int dimm_ranks[MLXBF_EDAC_MAX_DIMM_PER_MC];
+	void __iomem *emi_base;
+	int dimm_per_mc;
+};
+
+static u64 smc_call1(u64 smc_op, u64 smc_arg)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_smc(smc_op, smc_arg, 0, 0, 0, 0, 0, 0, &res);
+
+	return res.a0;
+}
+
+/*
+ * Gather the ECC information from the External Memory Interface registers
+ * and report it to the edac handler.
+ */
+static void bluefield_gather_report_ecc(struct mem_ctl_info *mci,
+					int error_cnt,
+					int is_single_ecc)
+{
+	struct bluefield_edac_priv *priv = mci->pvt_info;
+	u32 dram_additional_info, err_prank, edea0, edea1;
+	u32 ecc_latch_select, dram_syndrom, serr, derr, syndrom;
+	enum hw_event_mc_err_type ecc_type;
+	u64 ecc_dimm_addr;
+	int ecc_dimm;
+
+	ecc_type = is_single_ecc ? HW_EVENT_ERR_CORRECTED :
+				   HW_EVENT_ERR_UNCORRECTED;
+
+	/*
+	 * Tell the External Memory Interface to populate the relevant
+	 * registers with information about the last ECC error occurrence.
+	 */
+	ecc_latch_select = MLXBF_ECC_LATCH_SEL__START;
+	writel(ecc_latch_select, priv->emi_base + MLXBF_ECC_LATCH_SEL);
+
+	/*
+	 * Verify that the ECC reported info in the registers is of the
+	 * same type as the one asked to report. If not, just report the
+	 * error without the detailed information.
+	 */
+	dram_syndrom = readl(priv->emi_base + MLXBF_SYNDROM);
+	serr = FIELD_GET(MLXBF_SYNDROM__SERR, dram_syndrom);
+	derr = FIELD_GET(MLXBF_SYNDROM__DERR, dram_syndrom);
+	syndrom = FIELD_GET(MLXBF_SYNDROM__SYN, dram_syndrom);
+
+	if ((is_single_ecc && !serr) || (!is_single_ecc && !derr)) {
+		edac_mc_handle_error(ecc_type, mci, error_cnt, 0, 0, 0,
+				     0, 0, -1, mci->ctl_name, "");
+		return;
+	}
+
+	dram_additional_info = readl(priv->emi_base + MLXBF_ADD_INFO);
+	err_prank = FIELD_GET(MLXBF_ADD_INFO__ERR_PRANK, dram_additional_info);
+
+	ecc_dimm = (err_prank >= 2 && priv->dimm_ranks[0] <= 2) ? 1 : 0;
+
+	edea0 = readl(priv->emi_base + MLXBF_ERR_ADDR_0);
+	edea1 = readl(priv->emi_base + MLXBF_ERR_ADDR_1);
+
+	ecc_dimm_addr = ((u64)edea1 << 32) | edea0;
+
+	edac_mc_handle_error(ecc_type, mci, error_cnt,
+			     PFN_DOWN(ecc_dimm_addr),
+			     offset_in_page(ecc_dimm_addr),
+			     syndrom, ecc_dimm, 0, 0, mci->ctl_name, "");
+}
+
+static void bluefield_edac_check(struct mem_ctl_info *mci)
+{
+	struct bluefield_edac_priv *priv = mci->pvt_info;
+	u32 ecc_count, single_error_count, double_error_count, ecc_error = 0;
+
+	/*
+	 * The memory controller might not be initialized by the firmware
+	 * when there isn't memory, which may lead to bad register readings.
+	 */
+	if (mci->edac_cap == EDAC_FLAG_NONE)
+		return;
+
+	ecc_count = readl(priv->emi_base + MLXBF_ECC_CNT);
+	single_error_count = FIELD_GET(MLXBF_ECC_CNT__SERR_CNT, ecc_count);
+	double_error_count = FIELD_GET(MLXBF_ECC_CNT__DERR_CNT, ecc_count);
+
+	if (single_error_count) {
+		ecc_error |= MLXBF_ECC_ERR__SECC;
+
+		bluefield_gather_report_ecc(mci, single_error_count, 1);
+	}
+
+	if (double_error_count) {
+		ecc_error |= MLXBF_ECC_ERR__DECC;
+
+		bluefield_gather_report_ecc(mci, double_error_count, 0);
+	}
+
+	/* Write to clear reported errors. */
+	if (ecc_count)
+		writel(ecc_error, priv->emi_base + MLXBF_ECC_ERR);
+}
+
+/* Initialize the DIMMs information for the given memory controller. */
+static void bluefield_edac_init_dimms(struct mem_ctl_info *mci)
+{
+	struct bluefield_edac_priv *priv = mci->pvt_info;
+	int mem_ctrl_idx = mci->mc_idx;
+	struct dimm_info *dimm;
+	u64 smc_info, smc_arg;
+	int is_empty = 1, i;
+
+	for (i = 0; i < priv->dimm_per_mc; i++) {
+		dimm = mci->dimms[i];
+
+		smc_arg = mem_ctrl_idx << 16 | i;
+		smc_info = smc_call1(MLNX_SIP_GET_DIMM_INFO, smc_arg);
+
+		if (!FIELD_GET(MLXBF_DIMM_INFO__SIZE_GB, smc_info)) {
+			dimm->mtype = MEM_EMPTY;
+			continue;
+		}
+
+		is_empty = 0;
+
+		dimm->edac_mode = EDAC_SECDED;
+
+		if (FIELD_GET(MLXBF_DIMM_INFO__IS_NVDIMM, smc_info))
+			dimm->mtype = MEM_NVDIMM;
+		else if (FIELD_GET(MLXBF_DIMM_INFO__IS_LRDIMM, smc_info))
+			dimm->mtype = MEM_LRDDR4;
+		else if (FIELD_GET(MLXBF_DIMM_INFO__IS_RDIMM, smc_info))
+			dimm->mtype = MEM_RDDR4;
+		else
+			dimm->mtype = MEM_DDR4;
+
+		dimm->nr_pages =
+			FIELD_GET(MLXBF_DIMM_INFO__SIZE_GB, smc_info) *
+			(SZ_1G / PAGE_SIZE);
+		dimm->grain = MLXBF_EDAC_ERROR_GRAIN;
+
+		/* Mem controller for BlueField only supports x4, x8 and x16 */
+		switch (FIELD_GET(MLXBF_DIMM_INFO__PACKAGE_X, smc_info)) {
+		case 4:
+			dimm->dtype = DEV_X4;
+			break;
+		case 8:
+			dimm->dtype = DEV_X8;
+			break;
+		case 16:
+			dimm->dtype = DEV_X16;
+			break;
+		default:
+			dimm->dtype = DEV_UNKNOWN;
+		}
+
+		priv->dimm_ranks[i] =
+			FIELD_GET(MLXBF_DIMM_INFO__RANKS, smc_info);
+	}
+
+	if (is_empty)
+		mci->edac_cap = EDAC_FLAG_NONE;
+	else
+		mci->edac_cap = EDAC_FLAG_SECDED;
+}
+
+static int bluefield_edac_mc_probe(struct platform_device *pdev)
+{
+	struct bluefield_edac_priv *priv;
+	struct device *dev = &pdev->dev;
+	struct edac_mc_layer layers[1];
+	struct mem_ctl_info *mci;
+	struct resource *emi_res;
+	unsigned int mc_idx, dimm_count;
+	int rc, ret;
+
+	/* Read the MSS (Memory SubSystem) index from ACPI table. */
+	if (device_property_read_u32(dev, "mss_number", &mc_idx)) {
+		dev_warn(dev, "bf_edac: MSS number unknown\n");
+		return -EINVAL;
+	}
+
+	/* Read the DIMMs per MC from ACPI table. */
+	if (device_property_read_u32(dev, "dimm_per_mc", &dimm_count)) {
+		dev_warn(dev, "bf_edac: DIMMs per MC unknown\n");
+		return -EINVAL;
+	}
+
+	if (dimm_count > MLXBF_EDAC_MAX_DIMM_PER_MC) {
+		dev_warn(dev, "bf_edac: DIMMs per MC not valid\n");
+		return -EINVAL;
+	}
+
+	emi_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!emi_res)
+		return -EINVAL;
+
+	layers[0].type = EDAC_MC_LAYER_SLOT;
+	layers[0].size = dimm_count;
+	layers[0].is_virt_csrow = true;
+
+	mci = edac_mc_alloc(mc_idx, ARRAY_SIZE(layers), layers, sizeof(*priv));
+	if (!mci)
+		return -ENOMEM;
+
+	priv = mci->pvt_info;
+
+	priv->dimm_per_mc = dimm_count;
+	priv->emi_base = devm_ioremap_resource(dev, emi_res);
+	if (IS_ERR(priv->emi_base)) {
+		dev_err(dev, "failed to map EMI IO resource\n");
+		ret = PTR_ERR(priv->emi_base);
+		goto err;
+	}
+
+	mci->pdev = dev;
+	mci->mtype_cap = MEM_FLAG_DDR4 | MEM_FLAG_RDDR4 |
+			 MEM_FLAG_LRDDR4 | MEM_FLAG_NVDIMM;
+	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
+
+	mci->mod_name = DRIVER_NAME;
+	mci->ctl_name = "BlueField_Memory_Controller";
+	mci->dev_name = dev_name(dev);
+	mci->edac_check = bluefield_edac_check;
+
+	/* Initialize mci with the actual populated DIMM information. */
+	bluefield_edac_init_dimms(mci);
+
+	platform_set_drvdata(pdev, mci);
+
+	/* Register with EDAC core */
+	rc = edac_mc_add_mc(mci);
+	if (rc) {
+		dev_err(dev, "failed to register with EDAC core\n");
+		ret = rc;
+		goto err;
+	}
+
+	/* Only POLL mode supported so far. */
+	edac_op_state = EDAC_OPSTATE_POLL;
+
+	return 0;
+
+err:
+	edac_mc_free(mci);
+
+	return ret;
+
+}
+
+static int bluefield_edac_mc_remove(struct platform_device *pdev)
+{
+	struct mem_ctl_info *mci = platform_get_drvdata(pdev);
+
+	edac_mc_del_mc(&pdev->dev);
+	edac_mc_free(mci);
+
+	return 0;
+}
+
+static const struct acpi_device_id bluefield_mc_acpi_ids[] = {
+	{"MLNXBF08", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(acpi, bluefield_mc_acpi_ids);
+
+static struct platform_driver bluefield_edac_mc_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.acpi_match_table = bluefield_mc_acpi_ids,
+	},
+	.probe = bluefield_edac_mc_probe,
+	.remove = bluefield_edac_mc_remove,
+};
+
+module_platform_driver(bluefield_edac_mc_driver);
+
+MODULE_DESCRIPTION("Mellanox BlueField memory edac driver");
+MODULE_AUTHOR("Mellanox Technologies");
+MODULE_LICENSE("GPL v2");