[PATCH v6 1/1] EDAC, mellanox: Add ECC support for BlueField DDR4

[Shravan Kumar Ramani <sramani@mellanox.com>]

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 <james.morse@arm.com>
Signed-off-by: Shravan Kumar Ramani <sramani@mellanox.com>
---
 MAINTAINERS                   |   5 +
 drivers/edac/Kconfig          |   7 +
 drivers/edac/Makefile         |   1 +
 drivers/edac/bluefield_edac.c | 381 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 394 insertions(+)
 create mode 100644 drivers/edac/bluefield_edac.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d0ed735..a821587 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5669,6 +5669,11 @@ S:	Supported
 F:	drivers/edac/aspeed_edac.c
 F:	Documentation/devicetree/bindings/edac/aspeed-sdram-edac.txt
 
+EDAC-BLUEFIELD
+M:	Shravan Kumar Ramani <sramani@mellanox.com>
+S:	Supported
+F:	drivers/edac/bluefield_edac.c
+
 EDAC-CALXEDA
 M:	Robert Richter <rric@kernel.org>
 L:	linux-edac@vger.kernel.org
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 5e2e034..43df551 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -504,4 +504,11 @@ config EDAC_ASPEED
 	  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
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index 89ad4a84..0294a67 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -84,3 +84,4 @@ obj-$(CONFIG_EDAC_XGENE)		+= xgene_edac.o
 obj-$(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
diff --git a/drivers/edac/bluefield_edac.c b/drivers/edac/bluefield_edac.c
new file mode 100644
index 0000000..a0300a4
--- /dev/null
+++ b/drivers/edac/bluefield_edac.c
@@ -0,0 +1,381 @@
+// 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/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_SHIFT 0
+#define MLXBF_ECC_CNT__SERR_CNT_MASK 0xffff
+#define MLXBF_ECC_CNT__DERR_CNT_SHIFT 16
+#define MLXBF_ECC_CNT__DERR_CNT_MASK 0xffff
+
+#define MLXBF_ECC_ERR 0x348
+#define MLXBF_ECC_ERR__SECC_SHIFT 0
+#define MLXBF_ECC_ERR__DECC_SHIFT 16
+
+#define MLXBF_ECC_LATCH_SEL 0x354
+#define MLXBF_ECC_LATCH_SEL__START_SHIFT 24
+
+#define MLXBF_ERR_ADDR_0 0x358
+
+#define MLXBF_ERR_ADDR_1 0x37c
+
+#define MLXBF_SYNDROM 0x35c
+#define MLXBF_SYNDROM__DERR_SHIFT 0
+#define MLXBF_SYNDROM__DERR_MASK 0x1
+#define MLXBF_SYNDROM__SERR_SHIFT 1
+#define MLXBF_SYNDROM__SERR_MASK 0x1
+#define MLXBF_SYNDROM__SYN_SHIFT 16
+#define MLXBF_SYNDROM__SYN_MASK 0x3ff
+
+#define MLXBF_ADD_INFO 0x364
+#define MLXBF_ADD_INFO__ERR_PRANK_SHIFT 8
+#define MLXBF_ADD_INFO__ERR_PRANK_MASK 0x3
+
+#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_SHIFT 0
+#define MLXBF_DIMM_INFO__SIZE_GB_MASK 0xffff
+#define MLXBF_DIMM_INFO__IS_RDIMM_SHIFT 16
+#define MLXBF_DIMM_INFO__IS_RDIMM_MASK 0x1
+#define MLXBF_DIMM_INFO__IS_LRDIMM_SHIFT 17
+#define MLXBF_DIMM_INFO__IS_LRDIMM_MASK 0x1
+#define MLXBF_DIMM_INFO__IS_NVDIMM_SHIFT 18
+#define MLXBF_DIMM_INFO__IS_NVDIMM_MASK 0x1
+#define MLXBF_DIMM_INFO__RANKS_SHIFT 21
+#define MLXBF_DIMM_INFO__RANKS_MASK 0x7
+#define MLXBF_DIMM_INFO__PACKAGE_X_SHIFT 24
+#define MLXBF_DIMM_INFO__PACKAGE_X_MASK 0xff
+
+struct bluefield_edac_priv {
+	int dimm_ranks[MLXBF_EDAC_MAX_DIMM_PER_MC];
+	void __iomem *emi_base;
+	int dimm_per_mc;
+};
+
+static unsigned long smc_call1(unsigned long smc_op, unsigned long 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;
+	u32 ecc_latch_select = 0, dram_syndrom = 0, serr, derr, syndrom;
+	enum hw_event_mc_err_type ecc_type;
+	unsigned long ecc_dimm_addr;
+	int ecc_dimm;
+	u32 edea0;
+	u32 edea1;
+
+	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 |= 1 << MLXBF_ECC_LATCH_SEL__START_SHIFT;
+	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 = (dram_syndrom >> MLXBF_SYNDROM__SERR_SHIFT) &
+		MLXBF_SYNDROM__SERR_MASK;
+	derr = (dram_syndrom >> MLXBF_SYNDROM__DERR_SHIFT) &
+		MLXBF_SYNDROM__DERR_MASK;
+	syndrom = (dram_syndrom >> MLXBF_SYNDROM__SYN_SHIFT) &
+		MLXBF_SYNDROM__SYN_MASK;
+
+	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 = (dram_additional_info >> MLXBF_ADD_INFO__ERR_PRANK_SHIFT) &
+		MLXBF_ADD_INFO__ERR_PRANK_MASK;
+
+	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 = ((unsigned long)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 = (ecc_count >> MLXBF_ECC_CNT__SERR_CNT_SHIFT) &
+		MLXBF_ECC_CNT__SERR_CNT_MASK;
+	double_error_count = (ecc_count >> MLXBF_ECC_CNT__DERR_CNT_SHIFT) &
+		MLXBF_ECC_CNT__DERR_CNT_MASK;
+
+	if (single_error_count) {
+		ecc_error |= 1 << MLXBF_ECC_ERR__SECC_SHIFT;
+
+		bluefield_gather_report_ecc(mci, single_error_count, 1);
+	}
+
+	if (double_error_count) {
+		ecc_error |= 1 << MLXBF_ECC_ERR__DECC_SHIFT;
+
+		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;
+	unsigned long smc_info, smc_arg;
+	int is_empty = 1;
+	int 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 (!((smc_info >> MLXBF_DIMM_INFO__SIZE_GB_SHIFT) &
+			MLXBF_DIMM_INFO__SIZE_GB_MASK)) {
+			dimm->mtype = MEM_EMPTY;
+			continue;
+		}
+
+		is_empty = 0;
+
+		dimm->edac_mode = EDAC_SECDED;
+
+		if ((smc_info >> MLXBF_DIMM_INFO__IS_NVDIMM_SHIFT) &
+			MLXBF_DIMM_INFO__IS_NVDIMM_MASK)
+			dimm->mtype = MEM_NVDIMM;
+		else if ((smc_info >> MLXBF_DIMM_INFO__IS_LRDIMM_SHIFT) &
+			MLXBF_DIMM_INFO__IS_LRDIMM_MASK)
+			dimm->mtype = MEM_LRDDR4;
+		else if ((smc_info >> MLXBF_DIMM_INFO__IS_RDIMM_SHIFT) &
+			MLXBF_DIMM_INFO__IS_RDIMM_MASK)
+			dimm->mtype = MEM_RDDR4;
+		else
+			dimm->mtype = MEM_DDR4;
+
+		dimm->nr_pages = ((smc_info >> MLXBF_DIMM_INFO__SIZE_GB_SHIFT)
+			& MLXBF_DIMM_INFO__SIZE_GB_MASK) * (SZ_1G / PAGE_SIZE);
+		dimm->grain = MLXBF_EDAC_ERROR_GRAIN;
+
+		/* Mem controller for BlueField only supports x4, x8 and x16 */
+		switch ((smc_info >> MLXBF_DIMM_INFO__PACKAGE_X_SHIFT) &
+			MLXBF_DIMM_INFO__PACKAGE_X_MASK) {
+		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] =
+			(smc_info >> MLXBF_DIMM_INFO__RANKS_SHIFT) &
+			MLXBF_DIMM_INFO__RANKS_MASK;
+	}
+
+	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");
-- 
2.1.2