[mirror_ubuntu-hirsute-kernel.git] / drivers / bus / bt1-axi.c

// 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_OR_ZERO(axi->qos_regs);
}

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;
}

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;
}

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 (sysfs_streq(data, "bus"))
		readb(axi->qos_regs);
	else if (sysfs_streq(data, "unaligned"))
		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");
Commit	Line	Data
63cb7713 SS	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
	4	*
	5	* Authors:
	6	* Serge Semin <Sergey.Semin@baikalelectronics.ru>
	7	*
	8	* Baikal-T1 AXI-bus driver
	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/types.h>
	14	#include <linux/bitfield.h>
	15	#include <linux/device.h>
	16	#include <linux/atomic.h>
	17	#include <linux/regmap.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/mfd/syscon.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/io.h>
	22	#include <linux/nmi.h>
	23	#include <linux/of.h>
	24	#include <linux/clk.h>
	25	#include <linux/reset.h>
	26	#include <linux/sysfs.h>
	27
	28	#define BT1_AXI_WERRL 0x110
	29	#define BT1_AXI_WERRH 0x114
	30	#define BT1_AXI_WERRH_TYPE BIT(23)
	31	#define BT1_AXI_WERRH_ADDR_FLD 24
	32	#define BT1_AXI_WERRH_ADDR_MASK GENMASK(31, BT1_AXI_WERRH_ADDR_FLD)
	33
	34	/*
	35	* struct bt1_axi - Baikal-T1 AXI-bus private data
	36	* @dev: Pointer to the device structure.
	37	* @qos_regs: AXI Interconnect QoS tuning registers.
	38	* @sys_regs: Baikal-T1 System Controller registers map.
	39	* @irq: Errors IRQ number.
	40	* @aclk: AXI reference clock.
	41	* @arst: AXI Interconnect reset line.
	42	* @count: Number of errors detected.
	43	*/
	44	struct bt1_axi {
	45	struct device *dev;
	46
	47	void __iomem *qos_regs;
	48	struct regmap *sys_regs;
	49	int irq;
	50
	51	struct clk *aclk;
	52
	53	struct reset_control *arst;
	54
	55	atomic_t count;
	56	};
	57
	58	static irqreturn_t bt1_axi_isr(int irq, void *data)
	59	{
	60	struct bt1_axi *axi = data;
	61	u32 low = 0, high = 0;
	62
	63	regmap_read(axi->sys_regs, BT1_AXI_WERRL, &low);
	64	regmap_read(axi->sys_regs, BT1_AXI_WERRH, &high);
65
66	dev_crit_ratelimited(axi->dev,
67	"AXI-bus fault %d: %s at 0x%x%08x\n",
68	atomic_inc_return(&axi->count),
69	high & BT1_AXI_WERRH_TYPE ? "no slave" : "slave protocol error",
70	high, low);
71
72	/*
73	* Print backtrace on each CPU. This might be pointless if the fault
74	* has happened on the same CPU as the IRQ handler is executed or
75	* the other core proceeded further execution despite the error.
76	* But if it's not, by looking at the trace we would get straight to
77	* the cause of the problem.
78	*/
79	trigger_all_cpu_backtrace();
80
81	return IRQ_HANDLED;
82	}
83
84	static void bt1_axi_clear_data(void *data)
85	{
86	struct bt1_axi *axi = data;
87	struct platform_device *pdev = to_platform_device(axi->dev);
88
89	platform_set_drvdata(pdev, NULL);
90	}
91
92	static struct bt1_axi bt1_axi_create_data(struct platform_device pdev)
93	{
94	struct device *dev = &pdev->dev;
95	struct bt1_axi *axi;
96	int ret;
97
98	axi = devm_kzalloc(dev, sizeof(*axi), GFP_KERNEL);
99	if (!axi)
100	return ERR_PTR(-ENOMEM);
101
102	ret = devm_add_action(dev, bt1_axi_clear_data, axi);
103	if (ret) {
104	dev_err(dev, "Can't add AXI EHB data clear action\n");
105	return ERR_PTR(ret);
106	}
107
108	axi->dev = dev;
109	atomic_set(&axi->count, 0);
110	platform_set_drvdata(pdev, axi);
111
112	return axi;
113	}
114
115	static int bt1_axi_request_regs(struct bt1_axi *axi)
116	{
117	struct platform_device *pdev = to_platform_device(axi->dev);
118	struct device *dev = axi->dev;
119
120	axi->sys_regs = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
121	if (IS_ERR(axi->sys_regs)) {
122	dev_err(dev, "Couldn't find syscon registers\n");
123	return PTR_ERR(axi->sys_regs);
124	}
125
126	axi->qos_regs = devm_platform_ioremap_resource_byname(pdev, "qos");
7f57416f	127	if (IS_ERR(axi->qos_regs))
63cb7713	128	dev_err(dev, "Couldn't map AXI-bus QoS registers\n");
63cb7713	129
7f57416f	130	return PTR_ERR_OR_ZERO(axi->qos_regs);
63cb7713 SS	131	}
	132
	133	static int bt1_axi_request_rst(struct bt1_axi *axi)
	134	{
	135	int ret;
	136
	137	axi->arst = devm_reset_control_get_optional_exclusive(axi->dev, "arst");
	138	if (IS_ERR(axi->arst)) {
	139	dev_warn(axi->dev, "Couldn't get reset control line\n");
	140	return PTR_ERR(axi->arst);
	141	}
	142
	143	ret = reset_control_deassert(axi->arst);
	144	if (ret)
	145	dev_err(axi->dev, "Failed to deassert the reset line\n");
	146
	147	return ret;
	148	}
	149
	150	static void bt1_axi_disable_clk(void *data)
	151	{
	152	struct bt1_axi *axi = data;
	153
	154	clk_disable_unprepare(axi->aclk);
	155	}
	156
	157	static int bt1_axi_request_clk(struct bt1_axi *axi)
	158	{
	159	int ret;
	160
	161	axi->aclk = devm_clk_get(axi->dev, "aclk");
	162	if (IS_ERR(axi->aclk)) {
	163	dev_err(axi->dev, "Couldn't get AXI Interconnect clock\n");
	164	return PTR_ERR(axi->aclk);
	165	}
	166
	167	ret = clk_prepare_enable(axi->aclk);
	168	if (ret) {
	169	dev_err(axi->dev, "Couldn't enable the AXI clock\n");
	170	return ret;
	171	}
	172
	173	ret = devm_add_action_or_reset(axi->dev, bt1_axi_disable_clk, axi);
7f57416f	174	if (ret)
63cb7713	175	dev_err(axi->dev, "Can't add AXI clock disable action\n");
63cb7713	176
7f57416f	177	return ret;
63cb7713 SS	178	}
	179
	180	static int bt1_axi_request_irq(struct bt1_axi *axi)
	181	{
	182	struct platform_device *pdev = to_platform_device(axi->dev);
	183	int ret;
	184
	185	axi->irq = platform_get_irq(pdev, 0);
	186	if (axi->irq < 0)
	187	return axi->irq;
	188
	189	ret = devm_request_irq(axi->dev, axi->irq, bt1_axi_isr, IRQF_SHARED,
	190	"bt1-axi", axi);
7f57416f	191	if (ret)
63cb7713	192	dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n");
63cb7713	193
7f57416f	194	return ret;
63cb7713 SS	195	}
	196
	197	static ssize_t count_show(struct device *dev,
	198	struct device_attribute attr, char buf)
	199	{
	200	struct bt1_axi *axi = dev_get_drvdata(dev);
	201
	202	return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&axi->count));
	203	}
	204	static DEVICE_ATTR_RO(count);
	205
	206	static ssize_t inject_error_show(struct device *dev,
	207	struct device_attribute attr, char buf)
	208	{
	209	return scnprintf(buf, PAGE_SIZE, "Error injection: bus unaligned\n");
	210	}
	211
	212	static ssize_t inject_error_store(struct device *dev,
	213	struct device_attribute *attr,
	214	const char *data, size_t count)
	215	{
	216	struct bt1_axi *axi = dev_get_drvdata(dev);
	217
	218	/*
	219	* Performing unaligned read from the memory will cause the CM2 bus
	220	* error while unaligned writing - the AXI bus write error handled
	221	* by this driver.
	222	*/
91920088	223	if (sysfs_streq(data, "bus"))
63cb7713	224	readb(axi->qos_regs);
91920088	225	else if (sysfs_streq(data, "unaligned"))
63cb7713 SS	226	writeb(0, axi->qos_regs);
	227	else
	228	return -EINVAL;
	229
	230	return count;
	231	}
	232	static DEVICE_ATTR_RW(inject_error);
	233
	234	static struct attribute *bt1_axi_sysfs_attrs[] = {
	235	&dev_attr_count.attr,
	236	&dev_attr_inject_error.attr,
	237	NULL
	238	};
	239	ATTRIBUTE_GROUPS(bt1_axi_sysfs);
	240
	241	static void bt1_axi_remove_sysfs(void *data)
	242	{
	243	struct bt1_axi *axi = data;
	244
	245	device_remove_groups(axi->dev, bt1_axi_sysfs_groups);
	246	}
	247
	248	static int bt1_axi_init_sysfs(struct bt1_axi *axi)
	249	{
	250	int ret;
	251
	252	ret = device_add_groups(axi->dev, bt1_axi_sysfs_groups);
	253	if (ret) {
	254	dev_err(axi->dev, "Failed to add sysfs files group\n");
	255	return ret;
	256	}
	257
	258	ret = devm_add_action_or_reset(axi->dev, bt1_axi_remove_sysfs, axi);
	259	if (ret)
	260	dev_err(axi->dev, "Can't add AXI EHB sysfs remove action\n");
	261
	262	return ret;
	263	}
	264
	265	static int bt1_axi_probe(struct platform_device *pdev)
	266	{
	267	struct bt1_axi *axi;
	268	int ret;
	269
	270	axi = bt1_axi_create_data(pdev);
	271	if (IS_ERR(axi))
	272	return PTR_ERR(axi);
	273
	274	ret = bt1_axi_request_regs(axi);
	275	if (ret)
	276	return ret;
	277
	278	ret = bt1_axi_request_rst(axi);
	279	if (ret)
	280	return ret;
	281
	282	ret = bt1_axi_request_clk(axi);
	283	if (ret)
	284	return ret;
	285
	286	ret = bt1_axi_request_irq(axi);
	287	if (ret)
	288	return ret;
	289
290	ret = bt1_axi_init_sysfs(axi);
291	if (ret)
292	return ret;
293
294	return 0;
295	}
296
297	static const struct of_device_id bt1_axi_of_match[] = {
298	{ .compatible = "baikal,bt1-axi" },
299	{ }
300	};
301	MODULE_DEVICE_TABLE(of, bt1_axi_of_match);
302
303	static struct platform_driver bt1_axi_driver = {
304	.probe = bt1_axi_probe,
305	.driver = {
306	.name = "bt1-axi",
307	.of_match_table = bt1_axi_of_match
308	}
309	};
310	module_platform_driver(bt1_axi_driver);
311
312	MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
313	MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver");
314	MODULE_LICENSE("GPL v2");