apei: Add ACPI APEI event notification support

Add ACPI APEI event notification support for ARMv8 SoC under the following conditions:

1. Without EL3 support and no GPIO PIN available
2. With EL3 support but no mean to notify the OS

v2
* Make all code more generic naming
* Still waiting for comment from Linaro folks on APEI

Signed-off-by Loc Ho <[email protected]>

---
 drivers/edac/Kconfig     |    7 +++
 drivers/edac/Makefile    |    2 +
 drivers/edac/edac_apei.c |  114 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 123 insertions(+), 0 deletions(-)
 create mode 100644 drivers/edac/edac_apei.c

drivers/edac/Kconfig +7 -0

index ef25000..62c2bb2 100644
@@ -95,6 +95,13 @@ config EDAC_GHES
 
 	  In doubt, say 'Y'.
 
+config EDAC_APEI
+	tristate "ACPI APEI errors notification"
+	depends on ACPI_APEI && (ARM64 || COMPILE_TEST)
+	help
+	  APEI interface support for error notification via interrupt based
+	  for ARMv8 64-bit SOCs.
+
 config EDAC_AMD64
 	tristate "AMD64 (Opteron, Athlon64)"
 	depends on EDAC_MM_EDAC && AMD_NB && EDAC_DECODE_MCE

drivers/edac/Makefile +2 -0

index dbf53e0..9f91ff3 100644
@@ -19,6 +19,7 @@ edac_core-y	+= edac_pci.o edac_pci_sysfs.o
 endif
 
 obj-$(CONFIG_EDAC_GHES)			+= ghes_edac.o
+obj-$(CONFIG_EDAC_APEI)			+= edac_apei.o
 
 edac_mce_amd-y				:= mce_amd.o
 obj-$(CONFIG_EDAC_DECODE_MCE)		+= edac_mce_amd.o

@@ -70,3 +71,4 @@ obj-$(CONFIG_EDAC_OCTEON_PCI)		+= octeon_edac-pci.o
 obj-$(CONFIG_EDAC_ALTERA_MC)		+= altera_edac.o
 obj-$(CONFIG_EDAC_SYNOPSYS)		+= synopsys_edac.o
 obj-$(CONFIG_EDAC_XGENE)		+= xgene_edac.o
+

drivers/edac/edac_apei.c new file +114 -1

new file mode 100644
index 0000000..fd066f0
@@ -0,0 +1,114 @@
+/*
+ * APEI notification support for ARM 64-bit Soc's
+ *
+ * Copyright (c) 2015, Applied Micro Circuits Corporation
+ * Author: Tuan Phan <[email protected]>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This driver provides APEI error notification via interrupt with the UEFI
+ * FW for SoC processors under the following conditions:
+ *
+ * 1. No interrupt GPIO available or don't want to use one and no EL3 support
+ * 2. With EL3 support but no mean to interrupt the Linux OS that an event
+ *    has occurred.
+ *
+ */
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+struct edac_apei_dev {
+	void  __iomem	*csr_base;
+	struct device	*dev;
+	u32		irq;
+	acpi_handle	evt_handle;
+};
+
+static const struct acpi_device_id edac_apei_match[] = {
+	{ "APMC0D51", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, edac_apei_match);
+
+static irqreturn_t edac_apei_irq_handler(int irq, void *data)
+{
+	struct edac_apei_dev *ctx = (struct edac_apei_dev *) data;
+
+	/* Clear the interrupt */
+	writel(readl(ctx->csr_base), ctx->csr_base);
+
+	/* Send error event */
+	acpi_execute_simple_method(ctx->evt_handle, NULL, 0);
+
+	return IRQ_HANDLED;
+}
+
+static int edac_apei_probe(struct platform_device *pdev)
+{
+	struct edac_apei_dev *ctx;
+	struct resource *res;
+	acpi_handle evt_handle;
+	int rc;
+
+	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ctx);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ctx->csr_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ctx->csr_base)) {
+		dev_err(&pdev->dev, "No CSR resource\n");
+		return PTR_ERR(ctx->csr_base);
+	}
+
+	ctx->irq = platform_get_irq(pdev, 0);
+	if (ctx->irq < 0) {
+		dev_err(&pdev->dev, "No IRQ resource\n");
+		return ctx->irq;
+	}
+
+	rc = devm_request_irq(&pdev->dev, ctx->irq, edac_apei_irq_handler, 0,
+			      dev_name(&pdev->dev), ctx);
+	if (rc) {
+		dev_err(&pdev->dev, "Could not request IRQ %d\n", ctx->irq);
+		return rc;
+	}
+
+	if (!ACPI_SUCCESS(acpi_get_handle(ACPI_HANDLE(ctx->dev), "_EVT",
+					  &evt_handle)))
+		return AE_BAD_PARAMETER;
+
+	ctx->evt_handle = evt_handle;
+
+	return rc;
+}
+
+static struct platform_driver edac_apei_driver = {
+	.probe = edac_apei_probe,
+	.driver = {
+		.name = "edac-apei",
+		.acpi_match_table = ACPI_PTR(edac_apei_match),
+	},
+};
+module_platform_driver(edac_apei_driver);
+
+MODULE_DESCRIPTION("EDAC APEI driver");
+MODULE_AUTHOR("Tuan Phan <[email protected]>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");
--

1.7.1

Ok, so what's the strategy here?

I know Tomasz did some untangling of GHES stuff to make it load on ARM too and be arch-agnostic. The registration code in it is more than the tiny edac_apei_irq_handler().

So why is this thing a separate driver? It is called EDAC_APEI although it is ARM-specific.

Why can't it be part of ghes_edac.c with ARM-specific section, if absolutely needed?

If this is going to implement the ACPI spec, then I don't see anything vendor-, or arch-specific getting in the way except maybe that APMC0D51 id.

Hmmm?

I'm top-posting here because I'm adding some more ARM people to CC and would like for them to see the whole thing.

Ok, so what's the strategy here?

I know Tomasz did some untangling of GHES stuff to make it load on ARM too and be arch-agnostic. The registration code in it is more than the tiny edac_apei_irq_handler().

So why is this thing a separate driver? It is called EDAC_APEI although it is ARM-specific.

Why can't it be part of ghes_edac.c with ARM-specific section, if absolutely needed?

If this is going to implement the ACPI spec, then I don't see anything vendor-, or arch-specific getting in the way except maybe that APMC0D51 id.

Hmmm?

drivers/edac/edac_apei.c line 42

Quoted 3 lines

drivers/edac/edac_apei.c new file +3 -0

+static const struct acpi_device_id edac_apei_match[] = {
+	{ "APMC0D51", 0},
+	{},

[Thanks Boris for CC'ing me]

Hi all,

Sorry for the delay on this, I had to do some research and this isn't really my area of expertise.

Quoted 13 lines · Borislav Petkov

I'm top-posting here because I'm adding some more ARM people to CC and would like for them to see the whole thing.

Ok, so what's the strategy here?

I know Tomasz did some untangling of GHES stuff to make it load on ARM too and be arch-agnostic. The registration code in it is more than the tiny edac_apei_irq_handler().

So why is this thing a separate driver? It is called EDAC_APEI although it is ARM-specific.

Quoted 8 lines

Why can't it be part of ghes_edac.c with ARM-specific section, if absolutely needed?

If this is going to implement the ACPI spec, then I don't see anything vendor-, or arch-specific getting in the way except maybe that APMC0D51 id.

Hmmm?

I think you've hit the nail on the head. As far as I can tell, this is *not* conformant to ACPI APEI (which should be platform and architecture agnostic) and is actually an implementation-specific interface. However, I'm happy to be proven wrong if somebody can point me at a document describing ACPI APEI in a way that matches this implementation.

Quoted 3 lines

drivers/edac/edac_apei.c line 42

Quoted 3 lines

drivers/edac/edac_apei.c new file +3 -0

+static const struct acpi_device_id edac_apei_match[] = {
+    { "APMC0D51", 0},
+    {},

This, in particular, gives the game away methinks.

Will

Top post - quick reply - you are correct. This is a vendor specific implementation. APEI is generic, and in the general case there should not be a need to do anything with a special driver. Some will need their own special solution in the early days, but everyone else should be able to go generic. In particular I expect those implementing EL3 to do firmware first handling and to signal the event independently of any OS specific hooks.

Quoted 7 lines

Top post - quick reply - you are correct. This is a vendor specific implementation. APEI is generic, and in the general case there should not be a need to do anything with a special driver. Some will need their own special solution in the early days, but everyone else should be able to go generic. In particular I expect those implementing EL3 to do firmware first handling and to signal the event independently of any OS specific hooks.

In the meantime, I got these two patches:

https://lkml.kernel.org/r/1446857519-5908-1-git-send-email-lho at apm.com

which makes the GHES IRQ shared and, apparently solves the issue for APM.

I'd appreciate it if you guys took a look.