Date:   Thu, 14 Mar 2019 17:13:09 +0000
From:   Junhan Zhou <Junhan@...lanox.com>
To:     Junhan Zhou <Junhan@...lanox.com>, Borislav Petkov <bp@...en8.de>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
CC:     Liming Sun <lsun@...lanox.com>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v1 1/1] EDAC, mellanox: Add ECC support for BlueField DDR4

Hi, any comments on this patch?
I'm trying to add EDAC support for our BlueField platform memory controller.

> -----Original Message-----
> From: linux-edac-owner@...r.kernel.org <linux-edac-
> owner@...r.kernel.org> On Behalf Of Junhan Zhou
> Sent: Wednesday, February 27, 2019 3:22 PM
> To: Borislav Petkov <bp@...en8.de>; Mauro Carvalho Chehab
> <mchehab@...nel.org>
> Cc: Junhan Zhou <Junhan@...lanox.com>; Liming Sun
> <lsun@...lanox.com>; linux-edac@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: [PATCH v1 1/1] 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.
> 
> Signed-off-by: Junhan Zhou <Junhan@...lanox.com>
> ---
>  drivers/edac/Kconfig          |   7 +
>  drivers/edac/Makefile         |   1 +
>  drivers/edac/bluefield_edac.c | 425
> ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 433 insertions(+)
>  create mode 100644 drivers/edac/bluefield_edac.c
> 
> diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig index
> e286b5b..3bcb8fe 100644
> --- a/drivers/edac/Kconfig
> +++ b/drivers/edac/Kconfig
> @@ -475,4 +475,11 @@ config EDAC_QCOM
>  	  For debugging issues having to do with stability and overall system
>  	  health, you should probably say 'Y' here.
> 
> +config EDAC_BLUEFIELD
> +	tristate "Mellanox BlueField Memory ECC"
> +	depends on (MELLANOX_PLATFORM && ARM64 && 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
> 716096d..6dd5e67 100644
> --- a/drivers/edac/Makefile
> +++ b/drivers/edac/Makefile
> @@ -78,3 +78,4 @@ obj-$(CONFIG_EDAC_SYNOPSYS)		+=
> synopsys_edac.o
>  obj-$(CONFIG_EDAC_XGENE)		+= xgene_edac.o
>  obj-$(CONFIG_EDAC_TI)			+= ti_edac.o
>  obj-$(CONFIG_EDAC_QCOM)			+= qcom_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..bdcf0cc
> --- /dev/null
> +++ b/drivers/edac/bluefield_edac.c
> @@ -0,0 +1,425 @@
> +// 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.
> + * Registers which have individual bitfields have a union defining the
> + * bitfields following the address define.
> + */
> +
> +#define MLXBF_EMI_DRAM_ECC_COUNT 0x340
> +
> +union MLXBF_EMI_DRAM_ECC_COUNT_u {
> +	struct {
> +		/* ECC single errors counter */
> +		u32 single_error_count : 16;
> +		/* ECC double errors counter */
> +		u32 double_error_count : 16;
> +	};
> +
> +	u32 word;
> +};
> +
> +#define MLXBF_EMI_DRAM_ECC_ERROR 0x348
> +
> +union MLXBF_EMI_DRAM_ECC_ERROR_u {
> +	struct {
> +		/* 1 - ECC single error from DRAM wrapper x. */
> +		u32 dram_ecc_single : 1;
> +		/* Reserved. */
> +		u32 __reserved_0    : 15;
> +		/* 1 - ECC double error from DRAM wrapper x. */
> +		u32 dram_ecc_double : 1;
> +		/* Reserved. */
> +		u32 __reserved_1    : 15;
> +	};
> +
> +	u32 word;
> +};
> +
> +#define MLXBF_EMI_DRAM_ECC_LATCH_SELECT 0x354
> +
> +union MLXBF_EMI_DRAM_ECC_LATCH_SELECT_u {
> +	struct {
> +		/*
> +		 * For DRAM wrapper x.
> +		 *
> +		 * 0 - Last ECC error will be stored.
> +		 *
> +		 * 1 - First ECC error will be stored.
> +		 */
> +		u32 dram_ecc_first : 1;
> +		/* Reserved. */
> +		u32 __reserved_0   : 15;
> +		/* Selects to Edge (one of 8) to get the ECC info. */
> +		u32 edge_sel       : 4;
> +		/* Reserved. */
> +		u32 __reserved_1   : 4;
> +		/* 1 - Start select DRAM_INFO */
> +		u32 start          : 1;
> +		/* Reserved. */
> +		u32 __reserved_2   : 7;
> +	};
> +
> +	u32 word;
> +};
> +
> +#define MLXBF_EMI_DRAM_ERR_ADDR_0 0x358
> +
> +#define MLXBF_EMI_DRAM_ERR_ADDR_1 0x37c
> +
> +#define MLXBF_EMI_DRAM_SYNDROM 0x35c
> +
> +union MLXBF_EMI_DRAM_SYNDROM_u {
> +	struct {
> +		/* 1 - Double error. */
> +		u32 derr         : 1;
> +		/* 1 - Single error. */
> +		u32 serr         : 1;
> +		/* Reserved. */
> +		u32 __reserved_0 : 14;
> +		/* ECC syndrome (error bit according to the Hamming code).
> */
> +		u32 syndrom      : 10;
> +		/* Reserved. */
> +		u32 __reserved_1 : 6;
> +	};
> +
> +	u32 word;
> +};
> +
> +#define MLXBF_EMI_DRAM_ADDITIONAL_INFO_0 0x364
> +
> +union MLXBF_EMI_DRAM_ADDITIONAL_INFO_0_u {
> +	struct {
> +		/* Physical Error Bank. */
> +		u32 err_bank     : 4;
> +		/* Physical Error Logical Rank. */
> +		u32 err_lrank    : 2;
> +		/* Reserved. */
> +		u32 __reserved_0 : 2;
> +		/* Physical Error Physical Rank. */
> +		u32 err_prank    : 2;
> +		/* Reserved. */
> +		u32 __reserved_1 : 6;
> +		/* Error Edge Bitmap. */
> +		u32 err_edge     : 8;
> +		/* Reserved. */
> +		u32 __reserved_2 : 8;
> +	};
> +
> +	u32 word;
> +};
> +
> +#define MLXBF_EDAC_DIMM_PER_MC		2
> +#define MLXBF_EDAC_ERROR_GRAIN		8
> +
> +/*
> + * Request MLNX_SIP_GET_DIMM_INFO
> + *
> + * Retrieve information about DIMM on a certaion 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: dimm_info_smc union 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 */ union
> +dimm_info_smc {
> +	struct {
> +		unsigned long size_GB : 16;	/* Dimm size in GB */
> +		unsigned long is_rdimm : 1;	/* If is RDIMM/LRDIMM */
> +		unsigned long is_lrdimm : 1;	/* If is LRDIMM */
> +		unsigned long is_nvdimm : 1;	/* If is NVDIMM */
> +		unsigned long __reserved0 : 2;
> +		unsigned long ranks : 3;	/* Rank num of DIMM */
> +		unsigned long package_X : 8;	/* Bits per memory package
> */
> +		unsigned long __reserved1 : 32;
> +	};
> +	unsigned long val;
> +};
> +
> +struct bluefield_edac_priv {
> +	int dimm_ranks[MLXBF_EDAC_DIMM_PER_MC]; /* How many ranks
> in dimm */
> +	void __iomem *emi_base;
> +};
> +
> +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;
> +	union MLXBF_EMI_DRAM_ADDITIONAL_INFO_0_u edai0;
> +	union MLXBF_EMI_DRAM_ECC_LATCH_SELECT_u edels;
> +	union MLXBF_EMI_DRAM_SYNDROM_u eds;
> +	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 relavent
> +	 * registers with information about the last ECC error occurrence.
> +	 */
> +	edels.word = 0;
> +	edels.start = 1;
> +	writel(edels.word, priv->emi_base +
> MLXBF_EMI_DRAM_ECC_LATCH_SELECT);
> +
> +	/*
> +	 * 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.
> +	 */
> +	eds.word = readl(priv->emi_base + MLXBF_EMI_DRAM_SYNDROM);
> +
> +	if ((is_single_ecc && !eds.serr) || (!is_single_ecc && !eds.derr)) {
> +		edac_mc_handle_error(ecc_type, mci, error_cnt, 0, 0, 0,
> +				     0, 0, -1, mci->ctl_name, "");
> +		return;
> +	}
> +
> +	edai0.word = readl(priv->emi_base +
> MLXBF_EMI_DRAM_ADDITIONAL_INFO_0);
> +
> +	ecc_dimm = edai0.err_prank >= 2 && priv->dimm_ranks[0] <= 2;
> +
> +	edea0 = readl(priv->emi_base + MLXBF_EMI_DRAM_ERR_ADDR_0);
> +	edea1 = readl(priv->emi_base + MLXBF_EMI_DRAM_ERR_ADDR_1);
> +
> +	ecc_dimm_addr = ((unsigned long)edea1 << 32) | edea0;
> +
> +	edac_mc_handle_error(ecc_type, mci, error_cnt,
> +			     ecc_dimm_addr / 0x1000, ecc_dimm_addr & 0xfff,
> +			     eds.syndrom, ecc_dimm, 0, 0, mci->ctl_name, "");
> }
> +
> +static void bluefield_edac_check(struct mem_ctl_info *mci) {
> +	union MLXBF_EMI_DRAM_ECC_ERROR_u edee = { .word = 0 };
> +	struct bluefield_edac_priv *priv = mci->pvt_info;
> +	union MLXBF_EMI_DRAM_ECC_COUNT_u edec;
> +
> +	/*
> +	 * 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;
> +
> +	edec.word = readl(priv->emi_base +
> MLXBF_EMI_DRAM_ECC_COUNT);
> +
> +	if (edec.single_error_count != 0) {
> +		edee.dram_ecc_single = 1;
> +
> +		bluefield_gather_report_ecc(mci, edec.single_error_count,
> 1);
> +	}
> +
> +	if (edec.double_error_count != 0) {
> +		edee.dram_ecc_double = 1;
> +
> +		bluefield_gather_report_ecc(mci, edec.double_error_count,
> 0);
> +	}
> +
> +	/* Write to clear reported errors. */
> +	if (edec.word != 0)
> +		writel(edee.word, priv->emi_base +
> MLXBF_EMI_DRAM_ECC_ERROR); }
> +
> +/* 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;
> +	union dimm_info_smc smc_info;
> +	struct dimm_info *dimm;
> +	unsigned long smc_arg;
> +	int is_empty = 1;
> +	int i;
> +
> +	for (i = 0; i < MLXBF_EDAC_DIMM_PER_MC; i++) {
> +		dimm = mci->dimms[i];
> +
> +		smc_arg = mem_ctrl_idx << 16 | i;
> +		smc_info = (union dimm_info_smc) {
> +			.val = smc_call1(MLNX_SIP_GET_DIMM_INFO,
> smc_arg),
> +		};
> +
> +		if (smc_info.size_GB == 0) {
> +			dimm->mtype = MEM_EMPTY;
> +			continue;
> +		}
> +
> +		is_empty = 0;
> +
> +		dimm->edac_mode = EDAC_SECDED;
> +
> +		if (smc_info.is_nvdimm)
> +			dimm->mtype = MEM_NVDIMM;
> +		else if (smc_info.is_lrdimm)
> +			dimm->mtype = MEM_LRDDR4;
> +		else if (smc_info.is_rdimm)
> +			dimm->mtype = MEM_RDDR4;
> +		else
> +			dimm->mtype = MEM_DDR4;
> +
> +		dimm->nr_pages = smc_info.size_GB * 256 * 1024;
> +		dimm->grain = MLXBF_EDAC_ERROR_GRAIN;
> +
> +		/* Mem controller for BlueField only supports x4, x8 and x16
> */
> +		if (smc_info.package_X == 4)
> +			dimm->dtype = DEV_X4;
> +		else if (smc_info.package_X == 8)
> +			dimm->dtype = DEV_X8;
> +		else if (smc_info.package_X == 16)
> +			dimm->dtype = DEV_X16;
> +		else
> +			dimm->dtype = DEV_UNKNOWN;
> +
> +		priv->dimm_ranks[i] = smc_info.ranks;
> +	}
> +
> +	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;
> +	int rc, ret;
> +
> +	/* Only POLL mode supported so far. */
> +	edac_op_state = EDAC_OPSTATE_POLL;
> +
> +	/* 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;
> +	}
> +
> +	emi_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!emi_res)
> +		return -EINVAL;
> +
> +	layers[0].type = EDAC_MC_LAYER_SLOT;
> +	layers[0].size = MLXBF_EDAC_DIMM_PER_MC;
> +	layers[0].is_virt_csrow = true;
> +
> +	mci = edac_mc_alloc(mc_idx, ARRAY_SIZE(layers), layers,
> sizeof(*priv));
> +	if (mci == NULL)
> +		return -ENOMEM;
> +
> +	priv = mci->pvt_info;
> +
> +	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;
> +	}
> +
> +	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

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