EDAC/sifive: Add EDAC platform driver for SiFive SoCs

Add an EDAC driver for SiFive SoCs. The initial version supports ECC
event monitoring and reporting through the EDAC framework for the SiFive
L2 cache controller. It registers for notifier events from the L2 cache
controller driver (arch/riscv/mm/sifive_l2_cache.c) for L2 ECC events.

 [ bp: Massage commit message. ]

Signed-off-by: Yash Shah <yash.shah@sifive.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: linux-riscv@lists.infradead.org
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: sachin.ghadi@sifive.com
Link: https://lkml.kernel.org/r/1557142026-15949-2-git-send-email-yash.shah@sifive.com

MAINTAINERS

@@ -5809,6 +5809,12 @@ L:	linux-edac@vger.kernel.org
 S:	Maintained
 F:	drivers/edac/sb_edac.c
 
+EDAC-SIFIVE
+M:	Yash Shah <yash.shah@sifive.com>
+L:	linux-edac@vger.kernel.org
+S:	Supported
+F:	drivers/edac/sifive_edac.c
+
 EDAC-SKYLAKE
 M:	Tony Luck <tony.luck@intel.com>
 L:	linux-edac@vger.kernel.org

arch/riscv/Kconfig

@@ -50,6 +50,7 @@ config RISCV
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MMIOWB
 	select HAVE_EBPF_JIT if 64BIT
+	select EDAC_SUPPORT
 
 config MMU
 	def_bool y

drivers/edac/Kconfig

@@ -460,6 +460,12 @@ config EDAC_ALTERA_SDMMC
 	  Support for error detection and correction on the
 	  Altera SDMMC FIFO Memory for Altera SoCs.
 
+config EDAC_SIFIVE
+	bool "Sifive platform EDAC driver"
+	depends on EDAC=y && RISCV
+	help
+	  Support for error detection and correction on the SiFive SoCs.
+
 config EDAC_SYNOPSYS
 	tristate "Synopsys DDR Memory Controller"
 	depends on ARCH_ZYNQ || ARCH_ZYNQMP

drivers/edac/Makefile

@@ -79,6 +79,7 @@ obj-$(CONFIG_EDAC_OCTEON_PCI)		+= octeon_edac-pci.o
 obj-$(CONFIG_EDAC_THUNDERX)		+= thunderx_edac.o
 
 obj-$(CONFIG_EDAC_ALTERA)		+= altera_edac.o
+obj-$(CONFIG_EDAC_SIFIVE)		+= sifive_edac.o
 obj-$(CONFIG_EDAC_SYNOPSYS)		+= synopsys_edac.o
 obj-$(CONFIG_EDAC_XGENE)		+= xgene_edac.o
 obj-$(CONFIG_EDAC_TI)			+= ti_edac.o

drivers/edac/sifive_edac.c

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SiFive Platform EDAC Driver
+ *
+ * Copyright (C) 2018-2019 SiFive, Inc.
+ *
+ * This driver is partially based on octeon_edac-pc.c
+ *
+ */
+#include <linux/edac.h>
+#include <linux/platform_device.h>
+#include "edac_module.h"
+#include <asm/sifive_l2_cache.h>
+
+#define DRVNAME "sifive_edac"
+
+struct sifive_edac_priv {
+	struct notifier_block notifier;
+	struct edac_device_ctl_info *dci;
+};
+
+/**
+ * EDAC error callback
+ *
+ * @event: non-zero if unrecoverable.
+ */
+static
+int ecc_err_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	const char *msg = (char *)ptr;
+	struct sifive_edac_priv *p;
+
+	p = container_of(this, struct sifive_edac_priv, notifier);
+
+	if (event == SIFIVE_L2_ERR_TYPE_UE)
+		edac_device_handle_ue(p->dci, 0, 0, msg);
+	else if (event == SIFIVE_L2_ERR_TYPE_CE)
+		edac_device_handle_ce(p->dci, 0, 0, msg);
+
+	return NOTIFY_OK;
+}
+
+static int ecc_register(struct platform_device *pdev)
+{
+	struct sifive_edac_priv *p;
+
+	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	p->notifier.notifier_call = ecc_err_event;
+	platform_set_drvdata(pdev, p);
+
+	p->dci = edac_device_alloc_ctl_info(0, "sifive_ecc", 1, "sifive_ecc",
+					    1, 1, NULL, 0,
+					    edac_device_alloc_index());
+	if (IS_ERR(p->dci))
+		return PTR_ERR(p->dci);
+
+	p->dci->dev = &pdev->dev;
+	p->dci->mod_name = "Sifive ECC Manager";
+	p->dci->ctl_name = dev_name(&pdev->dev);
+	p->dci->dev_name = dev_name(&pdev->dev);
+
+	if (edac_device_add_device(p->dci)) {
+		dev_err(p->dci->dev, "failed to register with EDAC core\n");
+		goto err;
+	}
+
+	register_sifive_l2_error_notifier(&p->notifier);
+
+	return 0;
+
+err:
+	edac_device_free_ctl_info(p->dci);
+
+	return -ENXIO;
+}
+
+static int ecc_unregister(struct platform_device *pdev)
+{
+	struct sifive_edac_priv *p = platform_get_drvdata(pdev);
+
+	unregister_sifive_l2_error_notifier(&p->notifier);
+	edac_device_del_device(&pdev->dev);
+	edac_device_free_ctl_info(p->dci);
+
+	return 0;
+}
+
+static struct platform_device *sifive_pdev;
+
+static int __init sifive_edac_init(void)
+{
+	int ret;
+
+	sifive_pdev = platform_device_register_simple(DRVNAME, 0, NULL, 0);
+	if (IS_ERR(sifive_pdev))
+		return PTR_ERR(sifive_pdev);
+
+	ret = ecc_register(sifive_pdev);
+	if (ret)
+		platform_device_unregister(sifive_pdev);
+
+	return ret;
+}
+
+static void __exit sifive_edac_exit(void)
+{
+	ecc_unregister(sifive_pdev);
+	platform_device_unregister(sifive_pdev);
+}
+
+module_init(sifive_edac_init);
+module_exit(sifive_edac_exit);
+
+MODULE_AUTHOR("SiFive Inc.");
+MODULE_DESCRIPTION("SiFive platform EDAC driver");
+MODULE_LICENSE("GPL v2");