[PATCH v2 2/3] soc: amazon: al-pos: Introduce Amazon's Annapurna Labs POS driver

[Talel Shenhar <talel@amazon.com>]

The Amazon's Annapurna Labs SoCs includes Point Of Serialization error
logging unit that reports an error in case write error (e.g. attempt to
write to a read only register).
This patch introduces the support for this unit.

Signed-off-by: Talel Shenhar <talel@amazon.com>
---
 MAINTAINERS                 |   7 +++
 drivers/soc/Kconfig         |   1 +
 drivers/soc/Makefile        |   1 +
 drivers/soc/amazon/Kconfig  |   5 ++
 drivers/soc/amazon/Makefile |   1 +
 drivers/soc/amazon/al_pos.c | 127 ++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 142 insertions(+)
 create mode 100644 drivers/soc/amazon/Kconfig
 create mode 100644 drivers/soc/amazon/Makefile
 create mode 100644 drivers/soc/amazon/al_pos.c

diff --git a/MAINTAINERS b/MAINTAINERS
index e7a47b5..8c3a070 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -751,6 +751,13 @@ F:	drivers/tty/serial/altera_jtaguart.c
 F:	include/linux/altera_uart.h
 F:	include/linux/altera_jtaguart.h
 
+AMAZON ANNAPURNA LABS POS
+M:	Talel Shenhar <talel@amazon.com>
+M:	Talel Shenhar <talelshenhar@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/soc/amazon/amazon,al-pos.txt
+F:	drivers/soc/amazon/al_pos.c
+
 AMAZON ANNAPURNA LABS THERMAL MMIO DRIVER
 M:	Talel Shenhar <talel@amazon.com>
 S:	Maintained
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 833e04a..913a6b1 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -2,6 +2,7 @@
 menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/actions/Kconfig"
+source "drivers/soc/amazon/Kconfig"
 source "drivers/soc/amlogic/Kconfig"
 source "drivers/soc/aspeed/Kconfig"
 source "drivers/soc/atmel/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 2ec3550..c1c5c64 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -6,6 +6,7 @@
 obj-$(CONFIG_ARCH_ACTIONS)	+= actions/
 obj-$(CONFIG_SOC_ASPEED)	+= aspeed/
 obj-$(CONFIG_ARCH_AT91)		+= atmel/
+obj-y				+= amazon/
 obj-y				+= bcm/
 obj-$(CONFIG_ARCH_DOVE)		+= dove/
 obj-$(CONFIG_MACH_DOVE)		+= dove/
diff --git a/drivers/soc/amazon/Kconfig b/drivers/soc/amazon/Kconfig
new file mode 100644
index 00000000..fdd4cdd
--- /dev/null
+++ b/drivers/soc/amazon/Kconfig
@@ -0,0 +1,5 @@
+config AL_POS
+	bool "Amazon's Annapurna Labs POS driver"
+	depends on ARCH_ALPINE || COMPILE_TEST
+	help
+	  Include support for the SoC POS error capability.
diff --git a/drivers/soc/amazon/Makefile b/drivers/soc/amazon/Makefile
new file mode 100644
index 00000000..a31441a
--- /dev/null
+++ b/drivers/soc/amazon/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_AL_POS) += al_pos.o
diff --git a/drivers/soc/amazon/al_pos.c b/drivers/soc/amazon/al_pos.c
new file mode 100644
index 00000000..a865111
--- /dev/null
+++ b/drivers/soc/amazon/al_pos.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ */
+#include <linux/bitfield.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+/* Registers Offset */
+#define AL_POS_ERROR_LOG_1	0x0
+#define AL_POS_ERROR_LOG_0	0x4
+
+/* Registers Fields */
+#define AL_POS_ERROR_LOG_1_VALID	GENMASK(31, 31)
+#define AL_POS_ERROR_LOG_1_BRESP	GENMASK(18, 17)
+#define AL_POS_ERROR_LOG_1_REQUEST_ID	GENMASK(16, 8)
+#define AL_POS_ERROR_LOG_1_ADDR_HIGH	GENMASK(7, 0)
+
+#define AL_POS_ERROR_LOG_0_ADDR_LOW	GENMASK(31, 0)
+
+static int al_pos_panic;
+module_param(al_pos_panic, int, 0);
+MODULE_PARM_DESC(al_pos_panic, "Defines if POS error is causing panic()");
+
+struct al_pos {
+	struct platform_device *pdev;
+	void __iomem *mmio_base;
+	int irq;
+};
+
+static irqreturn_t al_pos_irq_handler(int irq, void *info)
+{
+	struct platform_device *pdev = info;
+	struct al_pos *pos = platform_get_drvdata(pdev);
+	u32 log1;
+	u32 log0;
+	u64 addr;
+	u16 request_id;
+	u8 bresp;
+
+	log1 = readl(pos->mmio_base + AL_POS_ERROR_LOG_1);
+	if (!FIELD_GET(AL_POS_ERROR_LOG_1_VALID, log1))
+		return IRQ_NONE;
+
+	log0 = readl(pos->mmio_base + AL_POS_ERROR_LOG_0);
+	writel(0, pos->mmio_base + AL_POS_ERROR_LOG_1);
+
+	addr = FIELD_GET(AL_POS_ERROR_LOG_0_ADDR_LOW, log0);
+	addr |= (FIELD_GET(AL_POS_ERROR_LOG_1_ADDR_HIGH, log1) << 32);
+	request_id = FIELD_GET(AL_POS_ERROR_LOG_1_REQUEST_ID, log1);
+	bresp = FIELD_GET(AL_POS_ERROR_LOG_1_BRESP, log1);
+
+	dev_err(&pdev->dev, "addr=0x%llx request_id=0x%x bresp=0x%x\n",
+		addr, request_id, bresp);
+
+	if (al_pos_panic)
+		panic("POS");
+
+	return IRQ_HANDLED;
+}
+
+static int al_pos_probe(struct platform_device *pdev)
+{
+	struct al_pos *pos;
+	int ret;
+
+	pos = devm_kzalloc(&pdev->dev, sizeof(*pos), GFP_KERNEL);
+	if (!pos)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, pos);
+	pos->pdev = pdev;
+
+	pos->mmio_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pos->mmio_base)) {
+		dev_err(&pdev->dev, "failed to ioremap memory (%ld)\n",
+			PTR_ERR(pos->mmio_base));
+		return PTR_ERR(pos->mmio_base);
+	}
+
+	pos->irq = platform_get_irq(pdev, 0);
+	if (pos->irq <= 0) {
+		dev_err(&pdev->dev, "fail to parse and map irq\n");
+		return -EINVAL;
+	}
+
+	ret = devm_request_irq(&pdev->dev,
+			       pos->irq,
+			       al_pos_irq_handler,
+			       0,
+			       pdev->name,
+			       pdev);
+	if (ret != 0) {
+		dev_err(&pdev->dev,
+			"failed to register to irq %d (%d)\n",
+			pos->irq, ret);
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "successfully loaded\n");
+
+	return 0;
+}
+
+static const struct of_device_id al_pos_of_match[] = {
+	{ .compatible = "amazon,al-pos", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, al_pos_of_match);
+
+static struct platform_driver al_pos_driver = {
+	.probe = al_pos_probe,
+	.driver = {
+		.name = "al-pos",
+		.of_match_table = al_pos_of_match,
+	},
+};
+
+module_platform_driver(al_pos_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Talel Shenhar");
+MODULE_DESCRIPTION("Amazon's Annapurna Labs POS driver");
-- 
2.7.4