[PATCH 5/6] edac: Add support for Krait CPU cache error detection

[Stephen Boyd]

Add support for the Krait CPU cache error detection. This is a
simplified version of the code originally written by Stepan
Moskovchenko[1] ported to the EDAC device framework.

[1] https://www.codeaurora.org/cgit/quic/la/kernel/msm/tree/arch/arm/mach-msm/cache_erp.c?h=msm-3.4

Cc: Stepan Moskovchenko <stepanm@xxxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---
 drivers/edac/Kconfig      |   8 ++
 drivers/edac/Makefile     |   2 +
 drivers/edac/krait_edac.c | 336 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 346 insertions(+)
 create mode 100644 drivers/edac/krait_edac.c

diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 878f090..68f612d 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -368,4 +368,12 @@ config EDAC_OCTEON_PCI
 	  Support for error detection and correction on the
 	  Cavium Octeon family of SOCs.
 
+config EDAC_KRAIT_CACHE
+	tristate "Krait L1/L2 Cache"
+	depends on EDAC_MM_EDAC && ARCH_MSM
+	select KRAIT_L2_ACCESSORS
+	help
+	  Support for error detection and correction on the
+	  Krait L1/L2 cache controller.
+
 endif # EDAC
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index 4154ed6..b6ea505 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -64,3 +64,5 @@ obj-$(CONFIG_EDAC_OCTEON_PC)		+= octeon_edac-pc.o
 obj-$(CONFIG_EDAC_OCTEON_L2C)		+= octeon_edac-l2c.o
 obj-$(CONFIG_EDAC_OCTEON_LMC)		+= octeon_edac-lmc.o
 obj-$(CONFIG_EDAC_OCTEON_PCI)		+= octeon_edac-pci.o
+
+obj-$(CONFIG_EDAC_KRAIT_CACHE)		+= krait_edac.o
diff --git a/drivers/edac/krait_edac.c b/drivers/edac/krait_edac.c
new file mode 100644
index 0000000..89380a1
--- /dev/null
+++ b/drivers/edac/krait_edac.c
@@ -0,0 +1,336 @@
+/* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/cpu.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#include <asm/krait-l2-accessors.h>
+
+#include "edac_core.h"
+
+#define CESR_DCTPE		BIT(0)
+#define CESR_DCDPE		BIT(1)
+#define CESR_ICTPE		BIT(2)
+#define CESR_ICDPE		BIT(3)
+#define CESR_DCTE		(BIT(4) | BIT(5))
+#define CESR_ICTE		(BIT(6) | BIT(7))
+#define CESR_TLBMH		BIT(16)
+#define CESR_I_MASK		0x000000cc
+/* Print a message for everything but TLB MH events */
+#define CESR_PRINT_MASK		0x000000ff
+
+#define L2ESR			0x204
+#define L2ESR_MPDCD		BIT(0)
+#define L2ESR_MPSLV		BIT(1)
+#define L2ESR_TSESB		BIT(2)
+#define L2ESR_TSEDB		BIT(3)
+#define L2ESR_DSESB		BIT(4)
+#define L2ESR_DSEDB		BIT(5)
+#define L2ESR_MSE		BIT(6)
+#define L2ESR_MPLDREXNOK	BIT(8)
+#define L2ESR_CPU_MASK		0xf
+#define L2ESR_CPU_SHIFT		16
+#define L2ESR_SP		BIT(20)
+
+#define L2ESYNR0		0x208
+#define L2ESYNR1		0x209
+#define L2EAR0			0x20c
+#define L2EAR1			0x20d
+
+struct krait_edac {
+	int l1_irq;
+	struct edac_device_ctl_info * __percpu *edev;
+	struct notifier_block notifier;
+};
+
+struct krait_edac_error {
+	const char * const msg;
+	void (*func)(struct edac_device_ctl_info *edac_dev,
+			int inst_nr, int block_nr, const char *msg);
+};
+
+static unsigned int read_cesr(void)
+{
+	unsigned int cesr;
+
+	asm volatile ("mrc p15, 7, %0, c15, c0, 1" : "=r" (cesr));
+	return cesr;
+}
+
+static void write_cesr(unsigned int cesr)
+{
+	asm volatile ("mcr p15, 7, %0, c15, c0, 1" : : "r" (cesr));
+}
+
+static unsigned int read_cesynr(void)
+{
+	unsigned int cesynr;
+
+	asm volatile ("mrc p15, 7, %0, c15, c0, 3" : "=r" (cesynr));
+	return cesynr;
+}
+
+static irqreturn_t krait_l1_irq(int irq, void *dev_id)
+{
+	struct edac_device_ctl_info *edac = dev_id;
+	unsigned int cesr = read_cesr();
+	unsigned int i_cesynr, d_cesynr;
+	unsigned int cpu = smp_processor_id();
+	int print_regs = cesr & CESR_PRINT_MASK;
+	int i;
+	static const struct krait_edac_error errors[] = {
+		{ "D-cache tag parity error", edac_device_handle_ue },
+		{ "D-cache data parity error", edac_device_handle_ue },
+		{ "I-cache tag parity error", edac_device_handle_ce },
+		{ "I-cache data parity error", edac_device_handle_ce },
+		{ "D-cache tag timing error", edac_device_handle_ue },
+		{ "D-cache data timing error", edac_device_handle_ue },
+		{ "I-cache tag timing error", edac_device_handle_ce },
+		{ "I-cache data timing error", edac_device_handle_ce }
+	};
+
+	if (print_regs) {
+		pr_alert("L1 / TLB Error detected on CPU %d!\n", cpu);
+		pr_alert("CESR      = 0x%08x\n", cesr);
+		pr_alert("MIDR      = 0x%08x\n", read_cpuid_id());
+	}
+
+	for (i = 0; i < ARRAY_SIZE(errors); i++)
+		if (BIT(i) & cesr)
+			errors[i].func(edac, cpu, 0, errors[i].msg);
+
+	if (cesr & CESR_TLBMH) {
+		asm ("mcr p15, 0, r0, c8, c7, 0");
+		edac_device_handle_ce(edac, cpu, 0, "TLB Multi-Hit error");
+	}
+
+	if (cesr & (CESR_ICTPE | CESR_ICDPE | CESR_ICTE)) {
+		i_cesynr = read_cesynr();
+		pr_alert("I-side CESYNR = 0x%08x\n", i_cesynr);
+		write_cesr(CESR_I_MASK);
+
+		/*
+		 * Clear the I-side bits from the captured CESR value so that we
+		 * don't accidentally clear any new I-side errors when we do
+		 * the CESR write-clear operation.
+		 */
+		cesr &= ~CESR_I_MASK;
+	}
+
+	if (cesr & (CESR_DCTPE | CESR_DCDPE | CESR_DCTE)) {
+		d_cesynr = read_cesynr();
+		pr_alert("D-side CESYNR = 0x%08x\n", d_cesynr);
+	}
+
+	/* Clear the interrupt bits we processed */
+	write_cesr(cesr);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t krait_l2_irq(int irq, void *dev_id)
+{
+	struct edac_device_ctl_info *edac = dev_id;
+	unsigned int l2esr;
+	unsigned int l2esynr0;
+	unsigned int l2esynr1;
+	unsigned int l2ear0;
+	unsigned int l2ear1;
+	unsigned long cpu;
+	int i;
+	static const struct krait_edac_error errors[] = {
+		{ "master port decode error", edac_device_handle_ce },
+		{ "master port slave error", edac_device_handle_ce },
+		{ "tag soft error, single-bit", edac_device_handle_ce },
+		{ "tag soft error, double-bit", edac_device_handle_ue },
+		{ "data soft error, single-bit", edac_device_handle_ce },
+		{ "data soft error, double-bit", edac_device_handle_ue },
+		{ "modified soft error", edac_device_handle_ce },
+		{ "slave port exclusive monitor not available",
+			edac_device_handle_ue},
+		{ "master port LDREX received Normal OK response",
+			edac_device_handle_ce },
+	};
+
+	l2esr = get_l2_indirect_reg(L2ESR);
+	pr_alert("Error detected!\n");
+	pr_alert("L2ESR    = 0x%08x\n", l2esr);
+
+	if (l2esr & (L2ESR_TSESB | L2ESR_TSEDB | L2ESR_MSE | L2ESR_SP)) {
+		l2esynr0 = get_l2_indirect_reg(L2ESYNR0);
+		l2esynr1 = get_l2_indirect_reg(L2ESYNR1);
+		l2ear0 = get_l2_indirect_reg(L2EAR0);
+		l2ear1 = get_l2_indirect_reg(L2EAR1);
+
+		pr_alert("L2ESYNR0 = 0x%08x\n", l2esynr0);
+		pr_alert("L2ESYNR1 = 0x%08x\n", l2esynr1);
+		pr_alert("L2EAR0   = 0x%08x\n", l2ear0);
+		pr_alert("L2EAR1   = 0x%08x\n", l2ear1);
+	}
+
+	cpu = (l2esr >> L2ESR_CPU_SHIFT) & L2ESR_CPU_MASK;
+	cpu = __ffs(cpu);
+	if (cpu)
+		cpu--;
+	for (i = 0; i < ARRAY_SIZE(errors); i++)
+		if (BIT(i) & l2esr)
+			errors[i].func(edac, cpu, 1, errors[i].msg);
+
+	set_l2_indirect_reg(L2ESR, l2esr);
+
+	return IRQ_HANDLED;
+}
+
+static void enable_l1_irq(void *info)
+{
+	const struct krait_edac *k = info;
+
+	enable_percpu_irq(k->l1_irq, IRQ_TYPE_LEVEL_HIGH);
+}
+
+static void disable_l1_irq(void *info)
+{
+	const struct krait_edac *k = info;
+
+	disable_percpu_irq(k->l1_irq);
+}
+
+static int
+krait_edac_notify(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+	struct krait_edac *p = container_of(nfb, struct krait_edac, notifier);
+
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_STARTING:
+		enable_l1_irq(p);
+		break;
+
+	case CPU_DYING:
+		disable_l1_irq(p);
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static int krait_edac_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct edac_device_ctl_info *edev;
+	struct krait_edac *p;
+	int l1_irq, l2_irq;
+	int ret;
+	int cpu;
+
+	l1_irq = platform_get_irq(pdev, 0);
+	if (l1_irq < 0)
+		return l1_irq;
+
+	l2_irq = platform_get_irq(pdev, 1);
+	if (l2_irq < 0)
+		return l2_irq;
+
+	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, p);
+	p->l1_irq = l1_irq;
+
+	p->edev = alloc_percpu(struct edac_device_ctl_info *);
+	if (!p->edev)
+		return -ENOMEM;
+
+	edev = edac_device_alloc_ctl_info(0, "cpu", num_possible_cpus(),
+						 "L", 2, 1, NULL, 0,
+						 edac_device_alloc_index());
+	if (!edev) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	edev->dev = dev;
+	edev->mod_name = dev_name(dev);
+	edev->dev_name = dev_name(dev);
+	edev->ctl_name = "cache";
+
+	for_each_possible_cpu(cpu)
+		*per_cpu_ptr(p->edev, cpu) = edev;
+
+	ret = edac_device_add_device(edev);
+	if (ret)
+		goto err_add;
+
+	ret = request_percpu_irq(l1_irq, krait_l1_irq, "[edac] L1 err",
+				p->edev);
+	if (ret)
+		goto err_l1_irq;
+
+	ret = devm_request_irq(dev, l2_irq, krait_l2_irq, 0, "[edac] L2 err",
+				edev);
+	if (ret)
+		goto err_l2_irq;
+
+	p->notifier.notifier_call = krait_edac_notify;
+	register_hotcpu_notifier(&p->notifier);
+	on_each_cpu(enable_l1_irq, p, true);
+
+	return 0;
+err_l2_irq:
+	free_percpu_irq(p->l1_irq, p->edev);
+err_l1_irq:
+	edac_device_del_device(dev);
+err_add:
+	edac_device_free_ctl_info(edev);
+err_alloc:
+	free_percpu(p->edev);
+	return ret;
+}
+
+static int krait_edac_remove(struct platform_device *pdev)
+{
+	struct krait_edac *p = platform_get_drvdata(pdev);
+
+	unregister_hotcpu_notifier(&p->notifier);
+	on_each_cpu(disable_l1_irq, p, true);
+	free_percpu_irq(p->l1_irq, p->edev);
+	edac_device_del_device(&pdev->dev);
+	edac_device_free_ctl_info(*__this_cpu_ptr(p->edev));
+	free_percpu(p->edev);
+
+	return 0;
+}
+
+static const struct of_device_id krait_edac_match_table[] = {
+	{ .compatible = "qcom,krait-cache-erp" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, krait_edac_match_table);
+
+static struct platform_driver krait_edac_driver = {
+	.probe = krait_edac_probe,
+	.remove = krait_edac_remove,
+	.driver = {
+		.name = "krait_edac",
+		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(krait_edac_match_table),
+	},
+};
+module_platform_driver(krait_edac_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Krait CPU cache error reporting driver");
+MODULE_ALIAS("platform:krait_edac");
-- 
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