[v7,2/2] EDAC/zynqmp: Add EDAC support for Xilinx ZynqMP OCM

diff --git a/MAINTAINERS b/MAINTAINERS
index edc96cdb85e8..2b6e74025549 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21692,6 +21692,13 @@  F:	Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
 F:	drivers/dma/xilinx/xilinx_dpdma.c
 F:	include/dt-bindings/dma/xlnx-zynqmp-dpdma.h
 
+XILINX ZYNQMP OCM EDAC DRIVER
+M:	Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
+M:	Sai Krishna Potthuri <sai.krishna.potthuri@amd.com>
+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 <anurag.kumar.vulisha@xilinx.com>
 M:	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 58ab63642e72..7944e40c67da 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -539,4 +539,13 @@  config EDAC_DMC520
 	  Support for error detection and correction on the
 	  SoCs with ARM DMC-520 DRAM controller.
 
+config EDAC_ZYNQMP_OCM
+	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.
+	  This driver can also be built as a module. If so, the module
+	  will be called zynqmp_ocm_edac.
+
 endif # EDAC
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index 2d1641a27a28..47cbda06d7b0 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -84,3 +84,4 @@  obj-$(CONFIG_EDAC_QCOM)			+= qcom_edac.o
 obj-$(CONFIG_EDAC_ASPEED)		+= aspeed_edac.o
 obj-$(CONFIG_EDAC_BLUEFIELD)		+= bluefield_edac.o
 obj-$(CONFIG_EDAC_DMC520)		+= dmc520_edac.o
+obj-$(CONFIG_EDAC_ZYNQMP_OCM)		+= zynqmp_edac.o
diff --git a/drivers/edac/zynqmp_edac.c b/drivers/edac/zynqmp_edac.c
new file mode 100644
index 000000000000..69069028457b
--- /dev/null
+++ b/drivers/edac/zynqmp_edac.c
@@ -0,0 +1,465 @@ 
+// 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 {
+		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 the ECC correctable and uncorrectable error.
+ */
+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.", irq);
+		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;
+
+	ue_bitpos = BIT(priv->ue_bitpos[0]) | BIT(priv->ue_bitpos[1]);
+
+	if (priv->ue_bitpos[0] == priv->ue_bitpos[1]) {
+		edac_printk(KERN_ERR, EDAC_DEVICE, "Bit positions should not be equal\n");
+		return -EINVAL;
+	}
+
+	if (priv->ue_bitpos[0] > UE_MAX_BITPOS_UPPER ||
+	    priv->ue_bitpos[1] > UE_MAX_BITPOS_UPPER)
+		return -EINVAL;
+
+	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);
+
+	if (IS_ENABLED(CONFIG_EDAC_DEBUG))
+		setup_debugfs(dci);
+
+	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);
+
+	if (IS_ENABLED(CONFIG_EDAC_DEBUG))
+		debugfs_remove_recursive(priv->debugfs_dir);
+
+	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");