bus: Add Baikal-T1 AXI-bus driver (63cb7713) · Commits · 戴 / test

drivers/bus/Kconfig

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		@@ -29,6 +29,21 @@ config BRCMSTB_GISB_ARB
		arbiter. This driver provides timeout and target abort error handling
		and internal bus master decoding.

		config BT1_AXI
		tristate "Baikal-T1 AXI-bus driver"
		depends on MIPS_BAIKAL_T1 \|\| COMPILE_TEST
		select MFD_SYSCON
		help
		AXI3-bus is the main communication bus connecting all high-speed
		peripheral IP-cores with RAM controller and with MIPS P5600 cores on
		Baikal-T1 SoC. Traffic arbitration is done by means of DW AMBA 3 AXI
		Interconnect (so called AXI Main Interconnect) routing IO requests
		from one SoC block to another. This driver provides a way to detect
		any bus protocol errors and device not responding situations by
		means of an embedded on top of the interconnect errors handler
		block (EHB). AXI Interconnect QoS arbitration tuning is currently
		unsupported.

		config MOXTET
		tristate "CZ.NIC Turris Mox module configuration bus"
		depends on SPI_MASTER && OF

drivers/bus/Makefile

+1 −0

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		@@ -13,6 +13,7 @@ obj-$(CONFIG_MOXTET) += moxtet.o
		# DPAA2 fsl-mc bus
		obj-$(CONFIG_FSL_MC_BUS) += fsl-mc/

		obj-$(CONFIG_BT1_AXI) += bt1-axi.o
		obj-$(CONFIG_IMX_WEIM) += imx-weim.o
		obj-$(CONFIG_MIPS_CDMM) += mips_cdmm.o
		obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o

drivers/bus/bt1-axi.c

0 → 100644

+320 −0

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		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
		*
		* Authors:
		* Serge Semin <Sergey.Semin@baikalelectronics.ru>
		*
		* Baikal-T1 AXI-bus driver
		*/

		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/types.h>
		#include <linux/bitfield.h>
		#include <linux/device.h>
		#include <linux/atomic.h>
		#include <linux/regmap.h>
		#include <linux/platform_device.h>
		#include <linux/mfd/syscon.h>
		#include <linux/interrupt.h>
		#include <linux/io.h>
		#include <linux/nmi.h>
		#include <linux/of.h>
		#include <linux/clk.h>
		#include <linux/reset.h>
		#include <linux/sysfs.h>

		#define BT1_AXI_WERRL 0x110
		#define BT1_AXI_WERRH 0x114
		#define BT1_AXI_WERRH_TYPE BIT(23)
		#define BT1_AXI_WERRH_ADDR_FLD 24
		#define BT1_AXI_WERRH_ADDR_MASK GENMASK(31, BT1_AXI_WERRH_ADDR_FLD)

		/*
		* struct bt1_axi - Baikal-T1 AXI-bus private data
		* @dev: Pointer to the device structure.
		* @qos_regs: AXI Interconnect QoS tuning registers.
		* @sys_regs: Baikal-T1 System Controller registers map.
		* @irq: Errors IRQ number.
		* @aclk: AXI reference clock.
		* @arst: AXI Interconnect reset line.
		* @count: Number of errors detected.
		*/
		struct bt1_axi {
		struct device *dev;

		void __iomem *qos_regs;
		struct regmap *sys_regs;
		int irq;

		struct clk *aclk;

		struct reset_control *arst;

		atomic_t count;
		};

		static irqreturn_t bt1_axi_isr(int irq, void *data)
		{
		struct bt1_axi *axi = data;
		u32 low = 0, high = 0;

		regmap_read(axi->sys_regs, BT1_AXI_WERRL, &low);
		regmap_read(axi->sys_regs, BT1_AXI_WERRH, &high);

		dev_crit_ratelimited(axi->dev,
		"AXI-bus fault %d: %s at 0x%x%08x\n",
		atomic_inc_return(&axi->count),
		high & BT1_AXI_WERRH_TYPE ? "no slave" : "slave protocol error",
		high, low);

		/*
		* Print backtrace on each CPU. This might be pointless if the fault
		* has happened on the same CPU as the IRQ handler is executed or
		* the other core proceeded further execution despite the error.
		* But if it's not, by looking at the trace we would get straight to
		* the cause of the problem.
		*/
		trigger_all_cpu_backtrace();

		return IRQ_HANDLED;
		}

		static void bt1_axi_clear_data(void *data)
		{
		struct bt1_axi *axi = data;
		struct platform_device *pdev = to_platform_device(axi->dev);

		platform_set_drvdata(pdev, NULL);
		}

		static struct bt1_axi bt1_axi_create_data(struct platform_device pdev)
		{
		struct device *dev = &pdev->dev;
		struct bt1_axi *axi;
		int ret;

		axi = devm_kzalloc(dev, sizeof(*axi), GFP_KERNEL);
		if (!axi)
		return ERR_PTR(-ENOMEM);

		ret = devm_add_action(dev, bt1_axi_clear_data, axi);
		if (ret) {
		dev_err(dev, "Can't add AXI EHB data clear action\n");
		return ERR_PTR(ret);
		}

		axi->dev = dev;
		atomic_set(&axi->count, 0);
		platform_set_drvdata(pdev, axi);

		return axi;
		}

		static int bt1_axi_request_regs(struct bt1_axi *axi)
		{
		struct platform_device *pdev = to_platform_device(axi->dev);
		struct device *dev = axi->dev;

		axi->sys_regs = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
		if (IS_ERR(axi->sys_regs)) {
		dev_err(dev, "Couldn't find syscon registers\n");
		return PTR_ERR(axi->sys_regs);
		}

		axi->qos_regs = devm_platform_ioremap_resource_byname(pdev, "qos");
		if (IS_ERR(axi->qos_regs)) {
		dev_err(dev, "Couldn't map AXI-bus QoS registers\n");
		return PTR_ERR(axi->qos_regs);
		}

		return 0;
		}

		static int bt1_axi_request_rst(struct bt1_axi *axi)
		{
		int ret;

		axi->arst = devm_reset_control_get_optional_exclusive(axi->dev, "arst");
		if (IS_ERR(axi->arst)) {
		dev_warn(axi->dev, "Couldn't get reset control line\n");
		return PTR_ERR(axi->arst);
		}

		ret = reset_control_deassert(axi->arst);
		if (ret)
		dev_err(axi->dev, "Failed to deassert the reset line\n");

		return ret;
		}

		static void bt1_axi_disable_clk(void *data)
		{
		struct bt1_axi *axi = data;

		clk_disable_unprepare(axi->aclk);
		}

		static int bt1_axi_request_clk(struct bt1_axi *axi)
		{
		int ret;

		axi->aclk = devm_clk_get(axi->dev, "aclk");
		if (IS_ERR(axi->aclk)) {
		dev_err(axi->dev, "Couldn't get AXI Interconnect clock\n");
		return PTR_ERR(axi->aclk);
		}

		ret = clk_prepare_enable(axi->aclk);
		if (ret) {
		dev_err(axi->dev, "Couldn't enable the AXI clock\n");
		return ret;
		}

		ret = devm_add_action_or_reset(axi->dev, bt1_axi_disable_clk, axi);
		if (ret) {
		dev_err(axi->dev, "Can't add AXI clock disable action\n");
		return ret;
		}

		return 0;
		}

		static int bt1_axi_request_irq(struct bt1_axi *axi)
		{
		struct platform_device *pdev = to_platform_device(axi->dev);
		int ret;

		axi->irq = platform_get_irq(pdev, 0);
		if (axi->irq < 0)
		return axi->irq;

		ret = devm_request_irq(axi->dev, axi->irq, bt1_axi_isr, IRQF_SHARED,
		"bt1-axi", axi);
		if (ret) {
		dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n");
		return ret;
		}

		return 0;
		}

		static ssize_t count_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		struct bt1_axi *axi = dev_get_drvdata(dev);

		return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&axi->count));
		}
		static DEVICE_ATTR_RO(count);

		static ssize_t inject_error_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		return scnprintf(buf, PAGE_SIZE, "Error injection: bus unaligned\n");
		}

		static ssize_t inject_error_store(struct device *dev,
		struct device_attribute *attr,
		const char *data, size_t count)
		{
		struct bt1_axi *axi = dev_get_drvdata(dev);

		/*
		* Performing unaligned read from the memory will cause the CM2 bus
		* error while unaligned writing - the AXI bus write error handled
		* by this driver.
		*/
		if (!strncmp(data, "bus", 3))
		readb(axi->qos_regs);
		else if (!strncmp(data, "unaligned", 9))
		writeb(0, axi->qos_regs);
		else
		return -EINVAL;

		return count;
		}
		static DEVICE_ATTR_RW(inject_error);

		static struct attribute *bt1_axi_sysfs_attrs[] = {
		&dev_attr_count.attr,
		&dev_attr_inject_error.attr,
		NULL
		};
		ATTRIBUTE_GROUPS(bt1_axi_sysfs);

		static void bt1_axi_remove_sysfs(void *data)
		{
		struct bt1_axi *axi = data;

		device_remove_groups(axi->dev, bt1_axi_sysfs_groups);
		}

		static int bt1_axi_init_sysfs(struct bt1_axi *axi)
		{
		int ret;

		ret = device_add_groups(axi->dev, bt1_axi_sysfs_groups);
		if (ret) {
		dev_err(axi->dev, "Failed to add sysfs files group\n");
		return ret;
		}

		ret = devm_add_action_or_reset(axi->dev, bt1_axi_remove_sysfs, axi);
		if (ret)
		dev_err(axi->dev, "Can't add AXI EHB sysfs remove action\n");

		return ret;
		}

		static int bt1_axi_probe(struct platform_device *pdev)
		{
		struct bt1_axi *axi;
		int ret;

		axi = bt1_axi_create_data(pdev);
		if (IS_ERR(axi))
		return PTR_ERR(axi);

		ret = bt1_axi_request_regs(axi);
		if (ret)
		return ret;

		ret = bt1_axi_request_rst(axi);
		if (ret)
		return ret;

		ret = bt1_axi_request_clk(axi);
		if (ret)
		return ret;

		ret = bt1_axi_request_irq(axi);
		if (ret)
		return ret;

		ret = bt1_axi_init_sysfs(axi);
		if (ret)
		return ret;

		return 0;
		}

		static const struct of_device_id bt1_axi_of_match[] = {
		{ .compatible = "baikal,bt1-axi" },
		{ }
		};
		MODULE_DEVICE_TABLE(of, bt1_axi_of_match);

		static struct platform_driver bt1_axi_driver = {
		.probe = bt1_axi_probe,
		.driver = {
		.name = "bt1-axi",
		.of_match_table = bt1_axi_of_match
		}
		};
		module_platform_driver(bt1_axi_driver);

		MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
		MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver");
		MODULE_LICENSE("GPL v2");

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