[PATCH 2/3] soc: sifive: beu: Add support for SiFive Bus Error Unit

Yash Shah yash.shah at sifive.com
Thu Nov 12 07:00:56 EST 2020


Add driver support for Bus Error Unit present in SiFive's FU740 chip.
Currently the driver reports erroneous events only using Platform-level
interrupts. The support for reporting events using hart-local interrupts
can be added in future.

Signed-off-by: Yash Shah <yash.shah at sifive.com>
---
 drivers/soc/sifive/Kconfig      |   5 +
 drivers/soc/sifive/Makefile     |   1 +
 drivers/soc/sifive/sifive_beu.c | 197 ++++++++++++++++++++++++++++++++++++++++
 include/soc/sifive/sifive_beu.h |  16 ++++
 4 files changed, 219 insertions(+)
 create mode 100644 drivers/soc/sifive/sifive_beu.c
 create mode 100644 include/soc/sifive/sifive_beu.h

diff --git a/drivers/soc/sifive/Kconfig b/drivers/soc/sifive/Kconfig
index 58cf8c4..d575fc1 100644
--- a/drivers/soc/sifive/Kconfig
+++ b/drivers/soc/sifive/Kconfig
@@ -7,4 +7,9 @@ config SIFIVE_L2
 	help
 	  Support for the L2 cache controller on SiFive platforms.
 
+config SIFIVE_BEU
+	bool "Sifive Bus Error Unit"
+	help
+	  Support for the Bus Error Unit on SiFive platforms.
+
 endif
diff --git a/drivers/soc/sifive/Makefile b/drivers/soc/sifive/Makefile
index b5caff7..1b43ecd 100644
--- a/drivers/soc/sifive/Makefile
+++ b/drivers/soc/sifive/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_SIFIVE_L2)	+= sifive_l2_cache.o
+obj-$(CONFIG_SIFIVE_BEU)	+= sifive_beu.o
diff --git a/drivers/soc/sifive/sifive_beu.c b/drivers/soc/sifive/sifive_beu.c
new file mode 100644
index 0000000..87b69ba
--- /dev/null
+++ b/drivers/soc/sifive/sifive_beu.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SiFive Bus Error Unit driver
+ * Copyright (C) 2020 SiFive
+ * Author: Yash Shah <yash.shah at sifive.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <soc/sifive/sifive_beu.h>
+
+#define SIFIVE_BEU_CAUSE	0x00
+#define SIFIVE_BEU_VALUE	0x08
+#define SIFIVE_BEU_ENABLE	0x10
+#define SIFIVE_BEU_PLIC_INTR	0x18
+#define SIFIVE_BEU_ACCRUED	0x20
+#define SIFIVE_BEU_LOCAL_INTR	0x28
+
+#define LOCAL_INTERRUPT	0
+#define PLIC_INTERRUPT	1
+#define MAX_ERR_EVENTS	5
+
+enum beu_err_events {
+	RESERVED = -1,
+	NO_ERR,
+	ITIM_CORR_ECC = 2,
+	ITIM_UNCORR_ECC,
+	TILINKBUS_ERR = 5,
+	DCACHE_CORR_ECC,
+	DCACHE_UNCORR_ECC
+};
+
+static
+int err_events[MAX_ERR_EVENTS] = {ITIM_CORR_ECC, ITIM_UNCORR_ECC, TILINKBUS_ERR,
+				  DCACHE_CORR_ECC, DCACHE_UNCORR_ECC};
+
+struct beu_sifive_ddata {
+	void __iomem *regs;
+	int irq;
+};
+
+static int beu_enable_event(struct beu_sifive_ddata *ddata,
+			    int event, int intr_type)
+{
+	unsigned char event_mask = BIT(event), val;
+
+	val = readb(ddata->regs + SIFIVE_BEU_ENABLE);
+	val |= event_mask;
+	writeb(val, ddata->regs + SIFIVE_BEU_ENABLE);
+
+	if (intr_type == PLIC_INTERRUPT) {
+		val = readb(ddata->regs + SIFIVE_BEU_PLIC_INTR);
+		val |= event_mask;
+		writeb(val, ddata->regs + SIFIVE_BEU_PLIC_INTR);
+	} else if (intr_type == LOCAL_INTERRUPT) {
+		val = readb(ddata->regs + SIFIVE_BEU_LOCAL_INTR);
+		val |= event_mask;
+		writeb(event_mask, ddata->regs + SIFIVE_BEU_LOCAL_INTR);
+	}
+
+	return 0;
+}
+
+static ATOMIC_NOTIFIER_HEAD(beu_chain);
+
+int register_sifive_beu_error_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_register(&beu_chain, nb);
+}
+
+int unregister_sifive_beu_error_notifier(struct notifier_block *nb)
+{
+	return atomic_notifier_chain_unregister(&beu_chain, nb);
+}
+
+static irqreturn_t beu_sifive_irq(int irq, void *data)
+{
+	struct beu_sifive_ddata *ddata = data;
+	unsigned char cause, addr;
+
+	addr = readb(ddata->regs + SIFIVE_BEU_VALUE);
+	cause = readb(ddata->regs + SIFIVE_BEU_CAUSE);
+	switch (cause) {
+	case NO_ERR:
+		break;
+	case ITIM_CORR_ECC:
+		pr_err("BEU: ITIM ECCFIX @ %d\n", addr);
+		atomic_notifier_call_chain(&beu_chain, SIFIVE_BEU_ERR_TYPE_CE,
+					   "ITIM ECCFIX");
+		break;
+	case ITIM_UNCORR_ECC:
+		pr_err("BEU: ITIM ECCFAIL @ %d\n", addr);
+		atomic_notifier_call_chain(&beu_chain, SIFIVE_BEU_ERR_TYPE_UE,
+					   "ITIM ECCFAIL");
+		break;
+	case TILINKBUS_ERR:
+		pr_err("BEU: Load or Store TILINK BUS ERR occurred\n");
+		break;
+	case DCACHE_CORR_ECC:
+		pr_err("BEU: DATACACHE ECCFIX @ %d\n", addr);
+		atomic_notifier_call_chain(&beu_chain, SIFIVE_BEU_ERR_TYPE_CE,
+					   "DCACHE ECCFIX");
+		break;
+	case DCACHE_UNCORR_ECC:
+		pr_err("BEU: DATACACHE ECCFAIL @ %d\n", addr);
+		atomic_notifier_call_chain(&beu_chain, SIFIVE_BEU_ERR_TYPE_UE,
+					   "DCACHE ECCFAIL");
+		break;
+	default:
+		pr_err("BEU: Unidentified cause\n");
+		break;
+	}
+	writeb(0, ddata->regs + SIFIVE_BEU_CAUSE);
+	writeb(0, ddata->regs + SIFIVE_BEU_ACCRUED);
+
+	return IRQ_HANDLED;
+}
+
+static int beu_sifive_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct beu_sifive_ddata *ddata;
+	struct resource *res;
+	int ret, i;
+
+	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ddata->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ddata->regs)) {
+		dev_err(dev, "Unable to map IO resources\n");
+		return PTR_ERR(ddata->regs);
+	}
+
+	ddata->irq = platform_get_irq(pdev, 0);
+	if (ddata->irq < 0) {
+		dev_err(dev, "Unable to find interrupt\n");
+		ret = ddata->irq;
+		return ret;
+	}
+
+	ret = devm_request_irq(dev, ddata->irq, beu_sifive_irq, 0,
+			       dev_name(dev), ddata);
+	if (ret) {
+		dev_err(dev, "Unable to request IRQ\n");
+		return ret;
+	}
+
+	for (i = 0; i < MAX_ERR_EVENTS; i++) {
+		ret = beu_enable_event(ddata, err_events[i], PLIC_INTERRUPT);
+		if (ret) {
+			dev_err(dev, "Unable to register PLIC interrupt\n");
+			return ret;
+		}
+	}
+
+	platform_set_drvdata(pdev, ddata);
+
+	return 0;
+}
+
+static int beu_sifive_remove(struct platform_device *pdev)
+{
+	struct beu_sifive_ddata *ddata = platform_get_drvdata(pdev);
+
+	/* Mask all error events */
+	writeb(0, ddata->regs + SIFIVE_BEU_ENABLE);
+	writeb(0, ddata->regs + SIFIVE_BEU_PLIC_INTR);
+	writeb(0, ddata->regs + SIFIVE_BEU_LOCAL_INTR);
+
+	return 0;
+}
+
+static const struct of_device_id beu_sifive_of_match[] = {
+	{ .compatible = "sifive,beu0" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, beu_sifive_of_match);
+
+static struct platform_driver beu_sifive_driver = {
+	.probe = beu_sifive_probe,
+	.remove = beu_sifive_remove,
+	.driver = {
+		.name = "beu-sifive",
+		.of_match_table = beu_sifive_of_match,
+	},
+};
+module_platform_driver(beu_sifive_driver);
+
+MODULE_DESCRIPTION("SiFive BEU driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/soc/sifive/sifive_beu.h b/include/soc/sifive/sifive_beu.h
new file mode 100644
index 0000000..c2ab688
--- /dev/null
+++ b/include/soc/sifive/sifive_beu.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SiFive Bus Error unit header file
+ *
+ */
+
+#ifndef __SOC_SIFIVE_BEU_H
+#define __SOC_SIFIVE_BEU_H
+
+extern int register_sifive_beu_error_notifier(struct notifier_block *nb);
+extern int unregister_sifive_beu_error_notifier(struct notifier_block *nb);
+
+#define SIFIVE_BEU_ERR_TYPE_CE 0
+#define SIFIVE_BEU_ERR_TYPE_UE 1
+
+#endif /* __SOC_SIFIVE_BEU_H */
-- 
2.7.4




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