EDAC, synps: Add EDAC support for zynq ddr ecc controller

Add EDAC support for ecc errors reporting on the synopsys ddr
controller. The ddr ecc controller corrects single bit errors and
detects double bit errors.

Selected important-ish notes from the changelog:

- I have not taken care of spliting synps_edac_geterror_info function as
it adds additional indentation levels and moreover the existing changes
were made as part of the v2 review comments

- Removed dt binding info as already there is a binding info available
under memorycontroller. so, updated ecc info there.

- Shortened the prefix "sysnopsys" to "synps"

Signed-off-by: Punnaiah Choudary Kalluri <punnaia@xilinx.com>
Link: http://lkml.kernel.org/r/a728a8d4678f4dbf9de189a480297c3d@BY2FFO11FD034.protection.gbl
[ Boris: massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>

MAINTAINERS

@@ -1583,6 +1583,7 @@ N:	xilinx
 F:	drivers/clocksource/cadence_ttc_timer.c
 F:	drivers/i2c/busses/i2c-cadence.c
 F:	drivers/mmc/host/sdhci-of-arasan.c
+F:	drivers/edac/synopsys_edac.c
 
 ARM SMMU DRIVER
 M:	Will Deacon <will.deacon@arm.com>

drivers/edac/Kconfig

@@ -385,4 +385,11 @@ config EDAC_ALTERA_MC
 	  preloader must initialize the SDRAM before loading
 	  the kernel.
 
+config EDAC_SYNOPSYS
+	tristate "Synopsys DDR Memory Controller"
+	depends on EDAC_MM_EDAC && ARCH_ZYNQ
+	help
+	  Support for error detection and correction on the Synopsys DDR
+	  memory controller.
+
 endif # EDAC

drivers/edac/Makefile

@@ -67,3 +67,4 @@ obj-$(CONFIG_EDAC_OCTEON_LMC)		+= octeon_edac-lmc.o
 obj-$(CONFIG_EDAC_OCTEON_PCI)		+= octeon_edac-pci.o
 
 obj-$(CONFIG_EDAC_ALTERA_MC)		+= altera_edac.o
+obj-$(CONFIG_EDAC_SYNOPSYS)		+= synopsys_edac.o

drivers/edac/synopsys_edac.c

@@ -0,0 +1,535 @@
+/*
+ * Synopsys DDR ECC Driver
+ * This driver is based on ppc4xx_edac.c drivers
+ *
+ * Copyright (C) 2012 - 2014 Xilinx, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details
+ */
+
+#include <linux/edac.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "edac_core.h"
+
+/* Number of cs_rows needed per memory controller */
+#define SYNPS_EDAC_NR_CSROWS	1
+
+/* Number of channels per memory controller */
+#define SYNPS_EDAC_NR_CHANS	1
+
+/* Granularity of reported error in bytes */
+#define SYNPS_EDAC_ERR_GRAIN	1
+
+#define SYNPS_EDAC_MSG_SIZE	256
+
+#define SYNPS_EDAC_MOD_STRING	"synps_edac"
+#define SYNPS_EDAC_MOD_VER	"1"
+
+/* Synopsys DDR memory controller registers that are relevant to ECC */
+#define CTRL_OFST		0x0
+#define T_ZQ_OFST		0xA4
+
+/* ECC control register */
+#define ECC_CTRL_OFST		0xC4
+/* ECC log register */
+#define CE_LOG_OFST		0xC8
+/* ECC address register */
+#define CE_ADDR_OFST		0xCC
+/* ECC data[31:0] register */
+#define CE_DATA_31_0_OFST	0xD0
+
+/* Uncorrectable error info registers */
+#define UE_LOG_OFST		0xDC
+#define UE_ADDR_OFST		0xE0
+#define UE_DATA_31_0_OFST	0xE4
+
+#define STAT_OFST		0xF0
+#define SCRUB_OFST		0xF4
+
+/* Control register bit field definitions */
+#define CTRL_BW_MASK		0xC
+#define CTRL_BW_SHIFT		2
+
+#define DDRCTL_WDTH_16		1
+#define DDRCTL_WDTH_32		0
+
+/* ZQ register bit field definitions */
+#define T_ZQ_DDRMODE_MASK	0x2
+
+/* ECC control register bit field definitions */
+#define ECC_CTRL_CLR_CE_ERR	0x2
+#define ECC_CTRL_CLR_UE_ERR	0x1
+
+/* ECC correctable/uncorrectable error log register definitions */
+#define LOG_VALID		0x1
+#define CE_LOG_BITPOS_MASK	0xFE
+#define CE_LOG_BITPOS_SHIFT	1
+
+/* ECC correctable/uncorrectable error address register definitions */
+#define ADDR_COL_MASK		0xFFF
+#define ADDR_ROW_MASK		0xFFFF000
+#define ADDR_ROW_SHIFT		12
+#define ADDR_BANK_MASK		0x70000000
+#define ADDR_BANK_SHIFT		28
+
+/* ECC statistic register definitions */
+#define STAT_UECNT_MASK		0xFF
+#define STAT_CECNT_MASK		0xFF00
+#define STAT_CECNT_SHIFT	8
+
+/* ECC scrub register definitions */
+#define SCRUB_MODE_MASK		0x7
+#define SCRUB_MODE_SECDED	0x4
+
+/**
+ * struct ecc_error_info - ECC error log information
+ * @row:	Row number
+ * @col:	Column number
+ * @bank:	Bank number
+ * @bitpos:	Bit position
+ * @data:	Data causing the error
+ */
+struct ecc_error_info {
+	u32 row;
+	u32 col;
+	u32 bank;
+	u32 bitpos;
+	u32 data;
+};
+
+/**
+ * struct synps_ecc_status - ECC status information to report
+ * @ce_cnt:	Correctable error count
+ * @ue_cnt:	Uncorrectable error count
+ * @ceinfo:	Correctable error log information
+ * @ueinfo:	Uncorrectable error log information
+ */
+struct synps_ecc_status {
+	u32 ce_cnt;
+	u32 ue_cnt;
+	struct ecc_error_info ceinfo;
+	struct ecc_error_info ueinfo;
+};
+
+/**
+ * struct synps_edac_priv - DDR memory controller private instance data
+ * @baseaddr:	Base address of the DDR controller
+ * @message:	Buffer for framing the event specific info
+ * @stat:	ECC status information
+ * @ce_cnt:	Correctable Error count
+ * @ue_cnt:	Uncorrectable Error count
+ */
+struct synps_edac_priv {
+	void __iomem *baseaddr;
+	char message[SYNPS_EDAC_MSG_SIZE];
+	struct synps_ecc_status stat;
+	u32 ce_cnt;
+	u32 ue_cnt;
+};
+
+/**
+ * synps_edac_geterror_info - Get the current ecc error info
+ * @base:	Pointer to the base address of the ddr memory controller
+ * @p:		Pointer to the synopsys ecc status structure
+ *
+ * Determines there is any ecc error or not
+ *
+ * Return: one if there is no error otherwise returns zero
+ */
+static int synps_edac_geterror_info(void __iomem *base,
+				    struct synps_ecc_status *p)
+{
+	u32 regval, clearval = 0;
+
+	regval = readl(base + STAT_OFST);
+	if (!regval)
+		return 1;
+
+	p->ce_cnt = (regval & STAT_CECNT_MASK) >> STAT_CECNT_SHIFT;
+	p->ue_cnt = regval & STAT_UECNT_MASK;
+
+	regval = readl(base + CE_LOG_OFST);
+	if (!(p->ce_cnt && (regval & LOG_VALID)))
+		goto ue_err;
+
+	p->ceinfo.bitpos = (regval & CE_LOG_BITPOS_MASK) >> CE_LOG_BITPOS_SHIFT;
+	regval = readl(base + CE_ADDR_OFST);
+	p->ceinfo.row = (regval & ADDR_ROW_MASK) >> ADDR_ROW_SHIFT;
+	p->ceinfo.col = regval & ADDR_COL_MASK;
+	p->ceinfo.bank = (regval & ADDR_BANK_MASK) >> ADDR_BANK_SHIFT;
+	p->ceinfo.data = readl(base + CE_DATA_31_0_OFST);
+	edac_dbg(3, "ce bit position: %d data: %d\n", p->ceinfo.bitpos,
+		 p->ceinfo.data);
+	clearval = ECC_CTRL_CLR_CE_ERR;
+
+ue_err:
+	regval = readl(base + UE_LOG_OFST);
+	if (!(p->ue_cnt && (regval & LOG_VALID)))
+		goto out;
+
+	regval = readl(base + UE_ADDR_OFST);
+	p->ueinfo.row = (regval & ADDR_ROW_MASK) >> ADDR_ROW_SHIFT;
+	p->ueinfo.col = regval & ADDR_COL_MASK;
+	p->ueinfo.bank = (regval & ADDR_BANK_MASK) >> ADDR_BANK_SHIFT;
+	p->ueinfo.data = readl(base + UE_DATA_31_0_OFST);
+	clearval |= ECC_CTRL_CLR_UE_ERR;
+
+out:
+	writel(clearval, base + ECC_CTRL_OFST);
+	writel(0x0, base + ECC_CTRL_OFST);
+
+	return 0;
+}
+
+/**
+ * synps_edac_handle_error - Handle controller error types CE and UE
+ * @mci:	Pointer to the edac memory controller instance
+ * @p:		Pointer to the synopsys ecc status structure
+ *
+ * Handles the controller ECC correctable and un correctable error.
+ */
+static void synps_edac_handle_error(struct mem_ctl_info *mci,
+				    struct synps_ecc_status *p)
+{
+	struct synps_edac_priv *priv = mci->pvt_info;
+	struct ecc_error_info *pinf;
+
+	if (p->ce_cnt) {
+		pinf = &p->ceinfo;
+		snprintf(priv->message, SYNPS_EDAC_MSG_SIZE,
+			 "DDR ECC error type :%s Row %d Bank %d Col %d ",
+			 "CE", pinf->row, pinf->bank, pinf->col);
+		edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci,
+				     p->ce_cnt, 0, 0, 0, 0, 0, -1,
+				     priv->message, "");
+	}
+
+	if (p->ue_cnt) {
+		pinf = &p->ueinfo;
+		snprintf(priv->message, SYNPS_EDAC_MSG_SIZE,
+			 "DDR ECC error type :%s Row %d Bank %d Col %d ",
+			 "UE", pinf->row, pinf->bank, pinf->col);
+		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci,
+				     p->ue_cnt, 0, 0, 0, 0, 0, -1,
+				     priv->message, "");
+	}
+
+	memset(p, 0, sizeof(*p));
+}
+
+/**
+ * synps_edac_check - Check controller for ECC errors
+ * @mci:	Pointer to the edac memory controller instance
+ *
+ * Used to check and post ECC errors. Called by the polling thread
+ */
+static void synps_edac_check(struct mem_ctl_info *mci)
+{
+	struct synps_edac_priv *priv = mci->pvt_info;
+	int status;
+
+	status = synps_edac_geterror_info(priv->baseaddr, &priv->stat);
+	if (status)
+		return;
+
+	priv->ce_cnt += priv->stat.ce_cnt;
+	priv->ue_cnt += priv->stat.ue_cnt;
+	synps_edac_handle_error(mci, &priv->stat);
+
+	edac_dbg(3, "Total error count ce %d ue %d\n",
+		 priv->ce_cnt, priv->ue_cnt);
+}
+
+/**
+ * synps_edac_get_dtype - Return the controller memory width
+ * @base:	Pointer to the ddr memory controller base address
+ *
+ * Get the EDAC device type width appropriate for the current controller
+ * configuration.
+ *
+ * Return: a device type width enumeration.
+ */
+static enum dev_type synps_edac_get_dtype(const void __iomem *base)
+{
+	enum dev_type dt;
+	u32 width;
+
+	width = readl(base + CTRL_OFST);
+	width = (width & CTRL_BW_MASK) >> CTRL_BW_SHIFT;
+
+	switch (width) {
+	case DDRCTL_WDTH_16:
+		dt = DEV_X2;
+		break;
+	case DDRCTL_WDTH_32:
+		dt = DEV_X4;
+		break;
+	default:
+		dt = DEV_UNKNOWN;
+	}
+
+	return dt;
+}
+
+/**
+ * synps_edac_get_eccstate - Return the controller ecc enable/disable status
+ * @base:	Pointer to the ddr memory controller base address
+ *
+ * Get the ECC enable/disable status for the controller
+ *
+ * Return: a ecc status boolean i.e true/false - enabled/disabled.
+ */
+static bool synps_edac_get_eccstate(void __iomem *base)
+{
+	enum dev_type dt;
+	u32 ecctype;
+	bool state = false;
+
+	dt = synps_edac_get_dtype(base);
+	if (dt == DEV_UNKNOWN)
+		return state;
+
+	ecctype = readl(base + SCRUB_OFST) & SCRUB_MODE_MASK;
+	if ((ecctype == SCRUB_MODE_SECDED) && (dt == DEV_X2))
+		state = true;
+
+	return state;
+}
+
+/**
+ * synps_edac_get_memsize - reads the size of the attached memory device
+ *
+ * Return: the memory size in bytes
+ */
+static u32 synps_edac_get_memsize(void)
+{
+	struct sysinfo inf;
+
+	si_meminfo(&inf);
+
+	return inf.totalram * inf.mem_unit;
+}
+
+/**
+ * synps_edac_get_mtype - Returns controller memory type
+ * @base:	pointer to the synopsys ecc status structure
+ *
+ * Get the EDAC memory type appropriate for the current controller
+ * configuration.
+ *
+ * Return: a memory type enumeration.
+ */
+static enum mem_type synps_edac_get_mtype(const void __iomem *base)
+{
+	enum mem_type mt;
+	u32 memtype;
+
+	memtype = readl(base + T_ZQ_OFST);
+
+	if (memtype & T_ZQ_DDRMODE_MASK)
+		mt = MEM_DDR3;
+	else
+		mt = MEM_DDR2;
+
+	return mt;
+}
+
+/**
+ * synps_edac_init_csrows - Initialize the cs row data
+ * @mci:	Pointer to the edac memory controller instance
+ *
+ * Initializes the chip select rows associated with the EDAC memory
+ * controller instance
+ *
+ * Return: Unconditionally 0.
+ */
+static int synps_edac_init_csrows(struct mem_ctl_info *mci)
+{
+	struct csrow_info *csi;
+	struct dimm_info *dimm;
+	struct synps_edac_priv *priv = mci->pvt_info;
+	u32 size;
+	int row, j;
+
+	for (row = 0; row < mci->nr_csrows; row++) {
+		csi = mci->csrows[row];
+		size = synps_edac_get_memsize();
+
+		for (j = 0; j < csi->nr_channels; j++) {
+			dimm            = csi->channels[j]->dimm;
+			dimm->edac_mode = EDAC_FLAG_SECDED;
+			dimm->mtype     = synps_edac_get_mtype(priv->baseaddr);
+			dimm->nr_pages  = (size >> PAGE_SHIFT) / csi->nr_channels;
+			dimm->grain     = SYNPS_EDAC_ERR_GRAIN;
+			dimm->dtype     = synps_edac_get_dtype(priv->baseaddr);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * synps_edac_mc_init - Initialize driver instance
+ * @mci:	Pointer to the edac memory controller instance
+ * @pdev:	Pointer to the platform_device struct
+ *
+ * Performs initialization of the EDAC memory controller instance and
+ * related driver-private data associated with the memory controller the
+ * instance is bound to.
+ *
+ * Return: Always zero.
+ */
+static int synps_edac_mc_init(struct mem_ctl_info *mci,
+				 struct platform_device *pdev)
+{
+	int status;
+	struct synps_edac_priv *priv;
+
+	mci->pdev = &pdev->dev;
+	priv = mci->pvt_info;
+	platform_set_drvdata(pdev, mci);
+
+	/* Initialize controller capabilities and configuration */
+	mci->mtype_cap = MEM_FLAG_DDR3 | MEM_FLAG_DDR2;
+	mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
+	mci->scrub_cap = SCRUB_HW_SRC;
+	mci->scrub_mode = SCRUB_NONE;
+
+	mci->edac_cap = EDAC_FLAG_SECDED;
+	mci->ctl_name = "synps_ddr_controller";
+	mci->dev_name = SYNPS_EDAC_MOD_STRING;
+	mci->mod_name = SYNPS_EDAC_MOD_VER;
+	mci->mod_ver = "1";
+
+	edac_op_state = EDAC_OPSTATE_POLL;
+	mci->edac_check = synps_edac_check;
+	mci->ctl_page_to_phys = NULL;
+
+	status = synps_edac_init_csrows(mci);
+
+	return status;
+}
+
+/**
+ * synps_edac_mc_probe - Check controller and bind driver
+ * @pdev:	Pointer to the platform_device struct
+ *
+ * Probes a specific controller instance for binding with the driver.
+ *
+ * Return: 0 if the controller instance was successfully bound to the
+ * driver; otherwise, < 0 on error.
+ */
+static int synps_edac_mc_probe(struct platform_device *pdev)
+{
+	struct mem_ctl_info *mci;
+	struct edac_mc_layer layers[2];
+	struct synps_edac_priv *priv;
+	int rc;
+	struct resource *res;
+	void __iomem *baseaddr;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	baseaddr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(baseaddr))
+		return PTR_ERR(baseaddr);
+
+	if (!synps_edac_get_eccstate(baseaddr)) {
+		edac_printk(KERN_INFO, EDAC_MC, "ECC not enabled\n");
+		return -ENXIO;
+	}
+
+	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
+	layers[0].size = SYNPS_EDAC_NR_CSROWS;
+	layers[0].is_virt_csrow = true;
+	layers[1].type = EDAC_MC_LAYER_CHANNEL;
+	layers[1].size = SYNPS_EDAC_NR_CHANS;
+	layers[1].is_virt_csrow = false;
+
+	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
+			    sizeof(struct synps_edac_priv));
+	if (!mci) {
+		edac_printk(KERN_ERR, EDAC_MC,
+			    "Failed memory allocation for mc instance\n");
+		return -ENOMEM;
+	}
+
+	priv = mci->pvt_info;
+	priv->baseaddr = baseaddr;
+	rc = synps_edac_mc_init(mci, pdev);
+	if (rc) {
+		edac_printk(KERN_ERR, EDAC_MC,
+			    "Failed to initialize instance\n");
+		goto free_edac_mc;
+	}
+
+	rc = edac_mc_add_mc(mci);
+	if (rc) {
+		edac_printk(KERN_ERR, EDAC_MC,
+			    "Failed to register with EDAC core\n");
+		goto free_edac_mc;
+	}
+
+	/*
+	 * Start capturing the correctable and uncorrectable errors. A write of
+	 * 0 starts the counters.
+	 */
+	writel(0x0, baseaddr + ECC_CTRL_OFST);
+	return rc;
+
+free_edac_mc:
+	edac_mc_free(mci);
+
+	return rc;
+}
+
+/**
+ * synps_edac_mc_remove - Unbind driver from controller
+ * @pdev:	Pointer to the platform_device struct
+ *
+ * Return: Unconditionally 0
+ */
+static int synps_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 struct of_device_id synps_edac_match[] = {
+	{ .compatible = "xlnx,zynq-ddrc-a05", },
+	{ /* end of table */ }
+};
+
+MODULE_DEVICE_TABLE(of, synps_edac_match);
+
+static struct platform_driver synps_edac_mc_driver = {
+	.driver = {
+		   .name = "synopsys-edac",
+		   .of_match_table = synps_edac_match,
+		   },
+	.probe = synps_edac_mc_probe,
+	.remove = synps_edac_mc_remove,
+};
+
+module_platform_driver(synps_edac_mc_driver);
+
+MODULE_AUTHOR("Xilinx Inc");
+MODULE_DESCRIPTION("Synopsys DDR ECC driver");
+MODULE_LICENSE("GPL v2");