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@xxxxxxxxxx>
---
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@xxxxxxxxxx>
+ *
+ */
+
+#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
