[v4,2/4] drivers: misc: Add Support for TMR Manager

diff --git a/Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager b/Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
new file mode 100644
index 000000000000..2a97be6ae849
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
@@ -0,0 +1,16 @@ 
+What:		/sys/devices/platform/amba_pl/<dev>/errcnt
+Date:		Sep 2022
+Contact:	appana.durga.kedareswara.rao@amd.com
+Description:	This control file provides the fault detection count.
+		This file cannot be written.
+		Example:
+		# cat /sys/devices/platform/amba_pl/44a10000.tmr_manager/errcnt
+		  1
+
+What:		/sys/devices/platform/amba_pl/<dev>/dis_block_break
+Date:		Sep 2022
+Contact:	appana.durga.kedareswara.rao@amd.com
+Description:	Write any value to it, This control file enables the break signal.
+		This file is write only.
+		Example:
+		# echo <any value> > /sys/devices/platform/amba_pl/44a10000.tmr_manager/dis_block_break
diff --git a/MAINTAINERS b/MAINTAINERS
index f1390b8270b2..5fc5ec13985e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13277,6 +13277,13 @@  W:	http://www.monstr.eu/fdt/
 T:	git git://git.monstr.eu/linux-2.6-microblaze.git
 F:	arch/microblaze/
 
+MICROBLAZE TMR MANAGER
+M:	Appana Durga Kedareswara rao <appana.durga.kedareswara.rao@amd.com>
+S:	Supported
+F:	Documentation/ABI/testing/sysfs-driver-xilinx-tmr-manager
+F:	Documentation/devicetree/bindings/misc/xlnx,tmr-manager.yaml
+F:	drivers/misc/xilinx_tmr_manager.c
+
 MICROCHIP AT91 DMA DRIVERS
 M:	Ludovic Desroches <ludovic.desroches@microchip.com>
 M:	Tudor Ambarus <tudor.ambarus@microchip.com>
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 94e9fb4cdd76..1508cc29b05a 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -496,6 +496,16 @@  config VCPU_STALL_DETECTOR
 
 	  If you do not intend to run this kernel as a guest, say N.
 
+config TMR_MANAGER
+	tristate "Select TMR Manager"
+	depends on MICROBLAZE && MB_MANAGER
+	help
+	  This option enables the driver developed for TMR Manager. The Triple
+	  Modular Redundancy(TMR) manager provides support for fault detection
+	  via sysfs interface.
+
+	  Say N here unless you know what you are doing.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 2be8542616dd..4918f6632531 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -60,4 +60,5 @@  obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
 obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
 obj-$(CONFIG_HI6421V600_IRQ)	+= hi6421v600-irq.o
 obj-$(CONFIG_OPEN_DICE)		+= open-dice.o
-obj-$(CONFIG_VCPU_STALL_DETECTOR)	+= vcpu_stall_detector.o
\ No newline at end of file
+obj-$(CONFIG_VCPU_STALL_DETECTOR)	+= vcpu_stall_detector.o
+obj-$(CONFIG_TMR_MANAGER)      += xilinx_tmr_manager.o
diff --git a/drivers/misc/xilinx_tmr_manager.c b/drivers/misc/xilinx_tmr_manager.c
new file mode 100644
index 000000000000..39365e0cb6e6
--- /dev/null
+++ b/drivers/misc/xilinx_tmr_manager.c
@@ -0,0 +1,222 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx TMR Subsystem.
+ *
+ * Copyright (C) 2022 Xilinx, Inc.
+ *
+ * Description:
+ * This driver is developed for TMR Manager,The Triple Modular Redundancy(TMR)
+ * Manager is responsible for handling the TMR subsystem state, including
+ * fault detection and error recovery. The core is triplicated in each of
+ * the sub-blocks in the TMR subsystem, and provides majority voting of
+ * its internal state provides soft error detection, correction and
+ * recovery. Error detection feature is provided through sysfs
+ * entries which allow the user to observer the TMR microblaze
+ * status.
+ */
+
+#include <asm/xilinx_mb_manager.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+/* TMR Manager Register offsets */
+#define XTMR_MANAGER_CR_OFFSET		0x0
+#define XTMR_MANAGER_FFR_OFFSET		0x4
+#define XTMR_MANAGER_CMR0_OFFSET	0x8
+#define XTMR_MANAGER_CMR1_OFFSET	0xC
+#define XTMR_MANAGER_BDIR_OFFSET	0x10
+#define XTMR_MANAGER_SEMIMR_OFFSET	0x1C
+
+/* Register Bitmasks/shifts */
+#define XTMR_MANAGER_CR_MAGIC1_MASK	GENMASK(7, 0)
+#define XTMR_MANAGER_CR_MAGIC2_MASK	GENMASK(15, 8)
+#define XTMR_MANAGER_CR_RIR_MASK	BIT(16)
+#define XTMR_MANAGER_FFR_LM12_MASK	BIT(0)
+#define XTMR_MANAGER_FFR_LM13_MASK	BIT(1)
+#define XTMR_MANAGER_FFR_LM23_MASK	BIT(2)
+
+#define XTMR_MANAGER_CR_MAGIC2_SHIFT	4
+#define XTMR_MANAGER_CR_RIR_SHIFT	16
+#define XTMR_MANAGER_CR_BB_SHIFT	18
+
+#define XTMR_MANAGER_MAGIC1_MAX_VAL	255
+
+/**
+ * struct xtmr_manager_dev - Driver data for TMR Manager
+ * @regs: device physical base address
+ * @cr_val: control register value
+ * @magic1: Magic 1 hardware configuration value
+ * @err_cnt: error statistics count
+ * @phys_baseaddr: Physical base address
+ */
+struct xtmr_manager_dev {
+	void __iomem *regs;
+	u32 cr_val;
+	u32 magic1;
+	u32 err_cnt;
+	resource_size_t phys_baseaddr;
+};
+
+/* IO accessors */
+static inline void xtmr_manager_write(struct xtmr_manager_dev *xtmr_manager,
+				      u32 addr, u32 value)
+{
+	iowrite32(value, xtmr_manager->regs + addr);
+}
+
+static inline u32 xtmr_manager_read(struct xtmr_manager_dev *xtmr_manager,
+				    u32 addr)
+{
+	return ioread32(xtmr_manager->regs + addr);
+}
+
+static void xmb_manager_reset_handler(struct xtmr_manager_dev *xtmr_manager)
+{
+	/* Clear the FFR Register contents as a part of recovery process. */
+	xtmr_manager_write(xtmr_manager, XTMR_MANAGER_FFR_OFFSET, 0);
+}
+
+static void xmb_manager_update_errcnt(struct xtmr_manager_dev *xtmr_manager)
+{
+	xtmr_manager->err_cnt++;
+}
+
+static ssize_t errcnt_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct xtmr_manager_dev *xtmr_manager = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%x\n", xtmr_manager->err_cnt);
+}
+static DEVICE_ATTR_RO(errcnt);
+
+static ssize_t dis_block_break_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t size)
+{
+	struct xtmr_manager_dev *xtmr_manager = dev_get_drvdata(dev);
+	int ret;
+	long value;
+
+	ret = kstrtoul(buf, 16, &value);
+	if (ret)
+		return ret;
+
+	/* unblock the break signal*/
+	xtmr_manager->cr_val &= ~(1 << XTMR_MANAGER_CR_BB_SHIFT);
+	xtmr_manager_write(xtmr_manager, XTMR_MANAGER_CR_OFFSET,
+			   xtmr_manager->cr_val);
+	return size;
+}
+static DEVICE_ATTR_WO(dis_block_break);
+
+static struct attribute *xtmr_manager_dev_attrs[] = {
+	&dev_attr_dis_block_break.attr,
+	&dev_attr_errcnt.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(xtmr_manager_dev);
+
+static void xtmr_manager_init(struct xtmr_manager_dev *xtmr_manager)
+{
+	/* Clear the SEM interrupt mask register to disable the interrupt */
+	xtmr_manager_write(xtmr_manager, XTMR_MANAGER_SEMIMR_OFFSET, 0);
+
+	/* Allow recovery reset by default */
+	xtmr_manager->cr_val = (1 << XTMR_MANAGER_CR_RIR_SHIFT) |
+				xtmr_manager->magic1;
+	xtmr_manager_write(xtmr_manager, XTMR_MANAGER_CR_OFFSET,
+			   xtmr_manager->cr_val);
+	/*
+	 * Configure Break Delay Initialization Register to zero so that
+	 * break occurs immediately
+	 */
+	xtmr_manager_write(xtmr_manager, XTMR_MANAGER_BDIR_OFFSET, 0);
+
+	/*
+	 * To come out of break handler need to block the break signal
+	 * in the tmr manager, update the xtmr_manager cr_val for the same
+	 */
+	xtmr_manager->cr_val |= (1 << XTMR_MANAGER_CR_BB_SHIFT);
+
+	/*
+	 * When the break vector gets asserted because of error injection,
+	 * the break signal must be blocked before exiting from the
+	 * break handler, Below api updates the TMR manager address and
+	 * control register and error counter callback arguments,
+	 * which will be used by the break handler to block the
+	 * break and call the callback function.
+	 */
+	xmb_manager_register(xtmr_manager->phys_baseaddr, xtmr_manager->cr_val,
+			     (void *)xmb_manager_update_errcnt,
+			     xtmr_manager, (void *)xmb_manager_reset_handler);
+}
+
+/**
+ * xtmr_manager_probe - Driver probe function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * This is the driver probe routine. It does all the memory
+ * allocation and creates sysfs entries for the device.
+ *
+ * Return: 0 on success and failure value on error
+ */
+static int xtmr_manager_probe(struct platform_device *pdev)
+{
+	struct xtmr_manager_dev *xtmr_manager;
+	struct resource *res;
+	int err;
+
+	xtmr_manager = devm_kzalloc(&pdev->dev, sizeof(*xtmr_manager),
+				    GFP_KERNEL);
+	if (!xtmr_manager)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	xtmr_manager->regs =  devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(xtmr_manager->regs))
+		return PTR_ERR(xtmr_manager->regs);
+
+	xtmr_manager->phys_baseaddr = res->start;
+
+	err = of_property_read_u32(pdev->dev.of_node, "xlnx,magic1",
+				   &xtmr_manager->magic1);
+	if (err < 0) {
+		dev_err(&pdev->dev, "unable to read xlnx,magic1 property");
+		return err;
+	}
+
+	if (xtmr_manager->magic1 > XTMR_MANAGER_MAGIC1_MAX_VAL) {
+		dev_err(&pdev->dev, "invalid xlnx,magic1 property value");
+		return -EINVAL;
+	}
+
+	/* Initialize TMR Manager */
+	xtmr_manager_init(xtmr_manager);
+
+	platform_set_drvdata(pdev, xtmr_manager);
+
+	return 0;
+}
+
+static const struct of_device_id xtmr_manager_of_match[] = {
+	{
+		.compatible = "xlnx,tmr-manager-1.0",
+	},
+	{ /* end of table */ }
+};
+MODULE_DEVICE_TABLE(of, xtmr_manager_of_match);
+
+static struct platform_driver xtmr_manager_driver = {
+	.driver = {
+		.name = "xilinx-tmr_manager",
+		.of_match_table = xtmr_manager_of_match,
+		.dev_groups = xtmr_manager_dev_groups,
+	},
+	.probe = xtmr_manager_probe,
+};
+module_platform_driver(xtmr_manager_driver);
+
+MODULE_AUTHOR("Xilinx, Inc");
+MODULE_DESCRIPTION("Xilinx TMR Manager Driver");
+MODULE_LICENSE("GPL");