EDAC/zynqmp: Add EDAC support for Xilinx ZynqMP OCM

Add EDAC support for Xilinx ZynqMP OCM Controller, so this driver reports CE and
UE errors upon interrupt generation. Also add debugfs files for error injection.

On Xilinx ZynqMP platform, both OCM Controller driver(zynqmp_edac) and DDR
Memory Controller driver(synopsys_edac) co-exist which means both can be loaded
at a time. This scenario is tested on Xilinx ZynqMP platform.

Fix following issue reported by the robot:
"MAINTAINERS references a file that doesn't exist:
Documentation/devicetree/bindings/edac/xlnx,zynqmp-ocmc.yaml"

[ bp:
- Massage commit message
- s/EDAC_ZYNQMP_OCM/EDAC_ZYNQMP/
- Touchups
]

Reported-by: kernel test robot <[e-mail]>
Co-developed-by: Shubhrajyoti Datta <[e-mail]>
Signed-off-by: Shubhrajyoti Datta <[e-mail]>
Signed-off-by: Sai Krishna Potthuri <[e-mail]>
Signed-off-by: Borislav Petkov (AMD) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

MAINTAINERS

···
 F:	drivers/dma/xilinx/xilinx_dpdma.c
 F:	include/dt-bindings/dma/xlnx-zynqmp-dpdma.h
 
+XILINX ZYNQMP OCM EDAC DRIVER
+M:	Shubhrajyoti Datta <[e-mail]>
+M:	Sai Krishna Potthuri <[e-mail]>
+S:	Maintained
+F:	Documentation/devicetree/bindings/memory-controllers/xlnx,zynqmp-ocmc-1.0.yaml
+F:	drivers/edac/zynqmp_edac.c
+
 XILINX ZYNQMP PSGTR PHY DRIVER
 M:	Anurag Kumar Vulisha <[e-mail]>
 M:	Laurent Pinchart <[e-mail]>

drivers/edac/Kconfig

···
 	  Support for error detection and correction on the
 	  SoCs with ARM DMC-520 DRAM controller.
 
+config EDAC_ZYNQMP
+	tristate "Xilinx ZynqMP OCM Controller"
+	depends on ARCH_ZYNQMP || COMPILE_TEST
+	help
+	  This driver supports error detection and correction for the
+	  Xilinx ZynqMP OCM (On Chip Memory) controller. It can also be
+	  built as a module. In that case it will be called zynqmp_edac.
+
 endif # EDAC

drivers/edac/Makefile

···
 obj-$(CONFIG_EDAC_ASPEED)		+= aspeed_edac.o
 obj-$(CONFIG_EDAC_BLUEFIELD)		+= bluefield_edac.o
 obj-$(CONFIG_EDAC_DMC520)		+= dmc520_edac.o
+obj-$(CONFIG_EDAC_ZYNQMP)		+= zynqmp_edac.o

drivers/edac/zynqmp_edac.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx ZynqMP OCM ECC Driver
+ *
+ * Copyright (C) 2022 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/edac.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include "edac_module.h"
+
+#define ZYNQMP_OCM_EDAC_MSG_SIZE	256
+
+#define ZYNQMP_OCM_EDAC_STRING	"zynqmp_ocm"
+
+/* Error/Interrupt registers */
+#define ERR_CTRL_OFST		0x0
+#define OCM_ISR_OFST		0x04
+#define OCM_IMR_OFST		0x08
+#define OCM_IEN_OFST		0x0C
+#define OCM_IDS_OFST		0x10
+
+/* ECC control register */
+#define ECC_CTRL_OFST		0x14
+
+/* Correctable error info registers */
+#define CE_FFA_OFST		0x1C
+#define CE_FFD0_OFST		0x20
+#define CE_FFD1_OFST		0x24
+#define CE_FFD2_OFST		0x28
+#define CE_FFD3_OFST		0x2C
+#define CE_FFE_OFST		0x30
+
+/* Uncorrectable error info registers */
+#define UE_FFA_OFST		0x34
+#define UE_FFD0_OFST		0x38
+#define UE_FFD1_OFST		0x3C
+#define UE_FFD2_OFST		0x40
+#define UE_FFD3_OFST		0x44
+#define UE_FFE_OFST		0x48
+
+/* ECC control register bit field definitions */
+#define ECC_CTRL_CLR_CE_ERR	0x40
+#define ECC_CTRL_CLR_UE_ERR	0x80
+
+/* Fault injection data and count registers */
+#define OCM_FID0_OFST		0x4C
+#define OCM_FID1_OFST		0x50
+#define OCM_FID2_OFST		0x54
+#define OCM_FID3_OFST		0x58
+#define OCM_FIC_OFST		0x74
+
+#define UE_MAX_BITPOS_LOWER	31
+#define UE_MIN_BITPOS_UPPER	32
+#define UE_MAX_BITPOS_UPPER	63
+
+/* Interrupt masks */
+#define OCM_CEINTR_MASK		BIT(6)
+#define OCM_UEINTR_MASK		BIT(7)
+#define OCM_ECC_ENABLE_MASK	BIT(0)
+
+#define OCM_FICOUNT_MASK	GENMASK(23, 0)
+#define OCM_NUM_UE_BITPOS	2
+#define OCM_BASEVAL		0xFFFC0000
+#define EDAC_DEVICE		"ZynqMP-OCM"
+
+/**
+ * struct ecc_error_info - ECC error log information
+ * @addr:	Fault generated at this address
+ * @fault_lo:	Generated fault data (lower 32-bit)
+ * @fault_hi:	Generated fault data (upper 32-bit)
+ */
+struct ecc_error_info {
+	u32 addr;
+	u32 fault_lo;
+	u32 fault_hi;
+};
+
+/**
+ * struct 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 ecc_status {
+	u32 ce_cnt;
+	u32 ue_cnt;
+	struct ecc_error_info ceinfo;
+	struct ecc_error_info ueinfo;
+};
+
+/**
+ * struct edac_priv - OCM private instance data
+ * @baseaddr:	Base address of the OCM
+ * @message:	Buffer for framing the event specific info
+ * @stat:	ECC status information
+ * @ce_cnt:	Correctable Error count
+ * @ue_cnt:	Uncorrectable Error count
+ * @debugfs_dir:	Directory entry for debugfs
+ * @ce_bitpos:	Bit position for Correctable Error
+ * @ue_bitpos:	Array to store UnCorrectable Error bit positions
+ * @fault_injection_cnt: Fault Injection Counter value
+ */
+struct edac_priv {
+	void __iomem *baseaddr;
+	char message[ZYNQMP_OCM_EDAC_MSG_SIZE];
+	struct ecc_status stat;
+	u32 ce_cnt;
+	u32 ue_cnt;
+#ifdef CONFIG_EDAC_DEBUG
+	struct dentry *debugfs_dir;
+	u8 ce_bitpos;
+	u8 ue_bitpos[OCM_NUM_UE_BITPOS];
+	u32 fault_injection_cnt;
+#endif
+};
+
+/**
+ * get_error_info - Get the current ECC error info
+ * @base:	Pointer to the base address of the OCM
+ * @p:		Pointer to the OCM ECC status structure
+ * @mask:	Status register mask value
+ *
+ * Determines there is any ECC error or not
+ *
+ */
+static void get_error_info(void __iomem *base, struct ecc_status *p, int mask)
+{
+	if (mask & OCM_CEINTR_MASK) {
+		p->ce_cnt++;
+		p->ceinfo.fault_lo = readl(base + CE_FFD0_OFST);
+		p->ceinfo.fault_hi = readl(base + CE_FFD1_OFST);
+		p->ceinfo.addr = (OCM_BASEVAL | readl(base + CE_FFA_OFST));
+		writel(ECC_CTRL_CLR_CE_ERR, base + OCM_ISR_OFST);
+	} else if (mask & OCM_UEINTR_MASK) {
+		p->ue_cnt++;
+		p->ueinfo.fault_lo = readl(base + UE_FFD0_OFST);
+		p->ueinfo.fault_hi = readl(base + UE_FFD1_OFST);
+		p->ueinfo.addr = (OCM_BASEVAL | readl(base + UE_FFA_OFST));
+		writel(ECC_CTRL_CLR_UE_ERR, base + OCM_ISR_OFST);
+	}
+}
+
+/**
+ * handle_error - Handle error types CE and UE
+ * @dci:	Pointer to the EDAC device instance
+ * @p:		Pointer to the OCM ECC status structure
+ *
+ * Handles correctable and uncorrectable errors.
+ */
+static void handle_error(struct edac_device_ctl_info *dci, struct ecc_status *p)
+{
+	struct edac_priv *priv = dci->pvt_info;
+	struct ecc_error_info *pinf;
+
+	if (p->ce_cnt) {
+		pinf = &p->ceinfo;
+		snprintf(priv->message, ZYNQMP_OCM_EDAC_MSG_SIZE,
+			 "\nOCM ECC error type :%s\nAddr: [0x%x]\nFault Data[0x%08x%08x]",
+			 "CE", pinf->addr, pinf->fault_hi, pinf->fault_lo);
+		edac_device_handle_ce(dci, 0, 0, priv->message);
+	}
+
+	if (p->ue_cnt) {
+		pinf = &p->ueinfo;
+		snprintf(priv->message, ZYNQMP_OCM_EDAC_MSG_SIZE,
+			 "\nOCM ECC error type :%s\nAddr: [0x%x]\nFault Data[0x%08x%08x]",
+			 "UE", pinf->addr, pinf->fault_hi, pinf->fault_lo);
+		edac_device_handle_ue(dci, 0, 0, priv->message);
+	}
+
+	memset(p, 0, sizeof(*p));
+}
+
+/**
+ * intr_handler - ISR routine
+ * @irq:        irq number
+ * @dev_id:     device id pointer
+ *
+ * Return: IRQ_NONE, if CE/UE interrupt not set or IRQ_HANDLED otherwise
+ */
+static irqreturn_t intr_handler(int irq, void *dev_id)
+{
+	struct edac_device_ctl_info *dci = dev_id;
+	struct edac_priv *priv = dci->pvt_info;
+	int regval;
+
+	regval = readl(priv->baseaddr + OCM_ISR_OFST);
+	if (!(regval & (OCM_CEINTR_MASK | OCM_UEINTR_MASK))) {
+		WARN_ONCE(1, "Unhandled IRQ%d, ISR: 0x%x", irq, regval);
+		return IRQ_NONE;
+	}
+
+	get_error_info(priv->baseaddr, &priv->stat, regval);
+
+	priv->ce_cnt += priv->stat.ce_cnt;
+	priv->ue_cnt += priv->stat.ue_cnt;
+	handle_error(dci, &priv->stat);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * get_eccstate - Return the ECC status
+ * @base:	Pointer to the OCM base address
+ *
+ * Get the ECC enable/disable status
+ *
+ * Return: ECC status 0/1.
+ */
+static bool get_eccstate(void __iomem *base)
+{
+	return readl(base + ECC_CTRL_OFST) & OCM_ECC_ENABLE_MASK;
+}
+
+#ifdef CONFIG_EDAC_DEBUG
+/**
+ * write_fault_count - write fault injection count
+ * @priv:	Pointer to the EDAC private struct
+ *
+ * Update the fault injection count register, once the counter reaches
+ * zero, it injects errors
+ */
+static void write_fault_count(struct edac_priv *priv)
+{
+	u32 ficount = priv->fault_injection_cnt;
+
+	if (ficount & ~OCM_FICOUNT_MASK) {
+		ficount &= OCM_FICOUNT_MASK;
+		edac_printk(KERN_INFO, EDAC_DEVICE,
+			    "Fault injection count value truncated to %d\n", ficount);
+	}
+
+	writel(ficount, priv->baseaddr + OCM_FIC_OFST);
+}
+
+/*
+ * To get the Correctable Error injected, the following steps are needed:
+ * - Setup the optional Fault Injection Count:
+ *	echo <fault_count val> > /sys/kernel/debug/edac/ocm/inject_fault_count
+ * - Write the Correctable Error bit position value:
+ *	echo <bit_pos val> > /sys/kernel/debug/edac/ocm/inject_ce_bitpos
+ */
+static ssize_t inject_ce_write(struct file *file, const char __user *data,
+			       size_t count, loff_t *ppos)
+{
+	struct edac_device_ctl_info *edac_dev = file->private_data;
+	struct edac_priv *priv = edac_dev->pvt_info;
+	int ret;
+
+	if (!data)
+		return -EFAULT;
+
+	ret = kstrtou8_from_user(data, count, 0, &priv->ce_bitpos);
+	if (ret)
+		return ret;
+
+	if (priv->ce_bitpos > UE_MAX_BITPOS_UPPER)
+		return -EINVAL;
+
+	if (priv->ce_bitpos <= UE_MAX_BITPOS_LOWER) {
+		writel(BIT(priv->ce_bitpos), priv->baseaddr + OCM_FID0_OFST);
+		writel(0, priv->baseaddr + OCM_FID1_OFST);
+	} else {
+		writel(BIT(priv->ce_bitpos - UE_MIN_BITPOS_UPPER),
+		       priv->baseaddr + OCM_FID1_OFST);
+		writel(0, priv->baseaddr + OCM_FID0_OFST);
+	}
+
+	write_fault_count(priv);
+
+	return count;
+}
+
+static const struct file_operations inject_ce_fops = {
+	.open = simple_open,
+	.write = inject_ce_write,
+	.llseek = generic_file_llseek,
+};
+
+/*
+ * To get the Uncorrectable Error injected, the following steps are needed:
+ * - Setup the optional Fault Injection Count:
+ *      echo <fault_count val> > /sys/kernel/debug/edac/ocm/inject_fault_count
+ * - Write the Uncorrectable Error bit position values:
+ *      echo <bit_pos0 val>,<bit_pos1 val> > /sys/kernel/debug/edac/ocm/inject_ue_bitpos
+ */
+static ssize_t inject_ue_write(struct file *file, const char __user *data,
+			       size_t count, loff_t *ppos)
+{
+	struct edac_device_ctl_info *edac_dev = file->private_data;
+	struct edac_priv *priv = edac_dev->pvt_info;
+	char buf[6], *pbuf, *token[2];
+	u64 ue_bitpos;
+	int i, ret;
+	u8 len;
+
+	if (!data)
+		return -EFAULT;
+
+	len = min_t(size_t, count, sizeof(buf));
+	if (copy_from_user(buf, data, len))
+		return -EFAULT;
+
+	buf[len] = '\0';
+	pbuf = &buf[0];
+	for (i = 0; i < OCM_NUM_UE_BITPOS; i++)
+		token[i] = strsep(&pbuf, ",");
+
+	ret = kstrtou8(token[0], 0, &priv->ue_bitpos[0]);
+	if (ret)
+		return ret;
+
+	ret = kstrtou8(token[1], 0, &priv->ue_bitpos[1]);
+	if (ret)
+		return ret;
+
+	if (priv->ue_bitpos[0] > UE_MAX_BITPOS_UPPER ||
+	    priv->ue_bitpos[1] > UE_MAX_BITPOS_UPPER)
+		return -EINVAL;
+
+	if (priv->ue_bitpos[0] == priv->ue_bitpos[1]) {
+		edac_printk(KERN_ERR, EDAC_DEVICE, "Bit positions should not be equal\n");
+		return -EINVAL;
+	}
+
+	ue_bitpos = BIT(priv->ue_bitpos[0]) | BIT(priv->ue_bitpos[1]);
+
+	writel((u32)ue_bitpos, priv->baseaddr + OCM_FID0_OFST);
+	writel((u32)(ue_bitpos >> 32), priv->baseaddr + OCM_FID1_OFST);
+
+	write_fault_count(priv);
+
+	return count;
+}
+
+static const struct file_operations inject_ue_fops = {
+	.open = simple_open,
+	.write = inject_ue_write,
+	.llseek = generic_file_llseek,
+};
+
+static void setup_debugfs(struct edac_device_ctl_info *edac_dev)
+{
+	struct edac_priv *priv = edac_dev->pvt_info;
+
+	priv->debugfs_dir = edac_debugfs_create_dir("ocm");
+	if (!priv->debugfs_dir)
+		return;
+
+	edac_debugfs_create_x32("inject_fault_count", 0644, priv->debugfs_dir,
+				&priv->fault_injection_cnt);
+	edac_debugfs_create_file("inject_ue_bitpos", 0644, priv->debugfs_dir,
+				 edac_dev, &inject_ue_fops);
+	edac_debugfs_create_file("inject_ce_bitpos", 0644, priv->debugfs_dir,
+				 edac_dev, &inject_ce_fops);
+}
+#endif
+
+static int edac_probe(struct platform_device *pdev)
+{
+	struct edac_device_ctl_info *dci;
+	struct edac_priv *priv;
+	void __iomem *baseaddr;
+	struct resource *res;
+	int irq, ret;
+
+	baseaddr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(baseaddr))
+		return PTR_ERR(baseaddr);
+
+	if (!get_eccstate(baseaddr)) {
+		edac_printk(KERN_INFO, EDAC_DEVICE, "ECC not enabled\n");
+		return -ENXIO;
+	}
+
+	dci = edac_device_alloc_ctl_info(sizeof(*priv), ZYNQMP_OCM_EDAC_STRING,
+					 1, ZYNQMP_OCM_EDAC_STRING, 1, 0, NULL, 0,
+					 edac_device_alloc_index());
+	if (!dci)
+		return -ENOMEM;
+
+	priv = dci->pvt_info;
+	platform_set_drvdata(pdev, dci);
+	dci->dev = &pdev->dev;
+	priv->baseaddr = baseaddr;
+	dci->mod_name = pdev->dev.driver->name;
+	dci->ctl_name = ZYNQMP_OCM_EDAC_STRING;
+	dci->dev_name = dev_name(&pdev->dev);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = irq;
+		goto free_dev_ctl;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, intr_handler, 0,
+			       dev_name(&pdev->dev), dci);
+	if (ret) {
+		edac_printk(KERN_ERR, EDAC_DEVICE, "Failed to request Irq\n");
+		goto free_dev_ctl;
+	}
+
+	/* Enable UE, CE interrupts */
+	writel((OCM_CEINTR_MASK | OCM_UEINTR_MASK), priv->baseaddr + OCM_IEN_OFST);
+
+#ifdef CONFIG_EDAC_DEBUG
+	setup_debugfs(dci);
+#endif
+
+	ret = edac_device_add_device(dci);
+	if (ret)
+		goto free_dev_ctl;
+
+	return 0;
+
+free_dev_ctl:
+	edac_device_free_ctl_info(dci);
+
+	return ret;
+}
+
+static int edac_remove(struct platform_device *pdev)
+{
+	struct edac_device_ctl_info *dci = platform_get_drvdata(pdev);
+	struct edac_priv *priv = dci->pvt_info;
+
+	/* Disable UE, CE interrupts */
+	writel((OCM_CEINTR_MASK | OCM_UEINTR_MASK), priv->baseaddr + OCM_IDS_OFST);
+
+#ifdef CONFIG_EDAC_DEBUG
+	debugfs_remove_recursive(priv->debugfs_dir);
+#endif
+
+	edac_device_del_device(&pdev->dev);
+	edac_device_free_ctl_info(dci);
+
+	return 0;
+}
+
+static const struct of_device_id zynqmp_ocm_edac_match[] = {
+	{ .compatible = "xlnx,zynqmp-ocmc-1.0"},
+	{ /* end of table */ }
+};
+
+MODULE_DEVICE_TABLE(of, zynqmp_ocm_edac_match);
+
+static struct platform_driver zynqmp_ocm_edac_driver = {
+	.driver = {
+		   .name = "zynqmp-ocm-edac",
+		   .of_match_table = zynqmp_ocm_edac_match,
+		   },
+	.probe = edac_probe,
+	.remove = edac_remove,
+};
+
+module_platform_driver(zynqmp_ocm_edac_driver);
+
+MODULE_AUTHOR("Advanced Micro Devices, Inc");
+MODULE_DESCRIPTION("Xilinx ZynqMP OCM ECC driver");
+MODULE_LICENSE("GPL");