RE: [PATCH 2/3] soc: sifive: beu: Add support for SiFive Bus Error Unit

[Yash Shah]

Any updates on this patch?

- Yash

> -----Original Message-----
> From: Yash Shah <yash.shah@xxxxxxxxxxxx>
> Sent: 12 November 2020 17:31
> To: robh+dt@xxxxxxxxxx; Paul Walmsley ( Sifive)
> <paul.walmsley@xxxxxxxxxx>; palmer@xxxxxxxxxxx; bp@xxxxxxxxx;
> mchehab@xxxxxxxxxx; tony.luck@xxxxxxxxx; james.morse@xxxxxxx;
> rric@xxxxxxxxxx
> Cc: aou@xxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> riscv@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> edac@xxxxxxxxxxxxxxx; Sachin Ghadi <sachin.ghadi@xxxxxxxxxxxx>; Yash
> Shah <yash.shah@xxxxxxxxxxxx>
> Subject: [PATCH 2/3] soc: sifive: beu: Add support for SiFive Bus Error Unit
> 
> Add driver support for Bus Error Unit present in SiFive's FU740 chip.
> Currently the driver reports erroneous events only using Platform-level
> interrupts. The support for reporting events using hart-local interrupts can
> be added in future.
> 
> Signed-off-by: Yash Shah <yash.shah@xxxxxxxxxx>
> ---
>  drivers/soc/sifive/Kconfig      |   5 +
>  drivers/soc/sifive/Makefile     |   1 +
>  drivers/soc/sifive/sifive_beu.c | 197
> ++++++++++++++++++++++++++++++++++++++++
>  include/soc/sifive/sifive_beu.h |  16 ++++
>  4 files changed, 219 insertions(+)
>  create mode 100644 drivers/soc/sifive/sifive_beu.c  create mode 100644
> include/soc/sifive/sifive_beu.h
> 
> diff --git a/drivers/soc/sifive/Kconfig b/drivers/soc/sifive/Kconfig index
> 58cf8c4..d575fc1 100644
> --- a/drivers/soc/sifive/Kconfig
> +++ b/drivers/soc/sifive/Kconfig
> @@ -7,4 +7,9 @@ config SIFIVE_L2
>  	help
>  	  Support for the L2 cache controller on SiFive platforms.
> 
> +config SIFIVE_BEU
> +	bool "Sifive Bus Error Unit"
> +	help
> +	  Support for the Bus Error Unit on SiFive platforms.
> +
>  endif
> diff --git a/drivers/soc/sifive/Makefile b/drivers/soc/sifive/Makefile index
> b5caff7..1b43ecd 100644
> --- a/drivers/soc/sifive/Makefile
> +++ b/drivers/soc/sifive/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0
> 
>  obj-$(CONFIG_SIFIVE_L2)	+= sifive_l2_cache.o
> +obj-$(CONFIG_SIFIVE_BEU)	+= sifive_beu.o
> diff --git a/drivers/soc/sifive/sifive_beu.c b/drivers/soc/sifive/sifive_beu.c
> new file mode 100644 index 0000000..87b69ba
> --- /dev/null
> +++ b/drivers/soc/sifive/sifive_beu.c
> @@ -0,0 +1,197 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * SiFive Bus Error Unit driver
> + * Copyright (C) 2020 SiFive
> + * Author: Yash Shah <yash.shah@xxxxxxxxxx>
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_platform.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <soc/sifive/sifive_beu.h>
> +
> +#define SIFIVE_BEU_CAUSE	0x00
> +#define SIFIVE_BEU_VALUE	0x08
> +#define SIFIVE_BEU_ENABLE	0x10
> +#define SIFIVE_BEU_PLIC_INTR	0x18
> +#define SIFIVE_BEU_ACCRUED	0x20
> +#define SIFIVE_BEU_LOCAL_INTR	0x28
> +
> +#define LOCAL_INTERRUPT	0
> +#define PLIC_INTERRUPT	1
> +#define MAX_ERR_EVENTS	5
> +
> +enum beu_err_events {
> +	RESERVED = -1,
> +	NO_ERR,
> +	ITIM_CORR_ECC = 2,
> +	ITIM_UNCORR_ECC,
> +	TILINKBUS_ERR = 5,
> +	DCACHE_CORR_ECC,
> +	DCACHE_UNCORR_ECC
> +};
> +
> +static
> +int err_events[MAX_ERR_EVENTS] = {ITIM_CORR_ECC, ITIM_UNCORR_ECC,
> TILINKBUS_ERR,
> +				  DCACHE_CORR_ECC,
> DCACHE_UNCORR_ECC};
> +
> +struct beu_sifive_ddata {
> +	void __iomem *regs;
> +	int irq;
> +};
> +
> +static int beu_enable_event(struct beu_sifive_ddata *ddata,
> +			    int event, int intr_type)
> +{
> +	unsigned char event_mask = BIT(event), val;
> +
> +	val = readb(ddata->regs + SIFIVE_BEU_ENABLE);
> +	val |= event_mask;
> +	writeb(val, ddata->regs + SIFIVE_BEU_ENABLE);
> +
> +	if (intr_type == PLIC_INTERRUPT) {
> +		val = readb(ddata->regs + SIFIVE_BEU_PLIC_INTR);
> +		val |= event_mask;
> +		writeb(val, ddata->regs + SIFIVE_BEU_PLIC_INTR);
> +	} else if (intr_type == LOCAL_INTERRUPT) {
> +		val = readb(ddata->regs + SIFIVE_BEU_LOCAL_INTR);
> +		val |= event_mask;
> +		writeb(event_mask, ddata->regs + SIFIVE_BEU_LOCAL_INTR);
> +	}
> +
> +	return 0;
> +}
> +
> +static ATOMIC_NOTIFIER_HEAD(beu_chain);
> +
> +int register_sifive_beu_error_notifier(struct notifier_block *nb) {
> +	return atomic_notifier_chain_register(&beu_chain, nb); }
> +
> +int unregister_sifive_beu_error_notifier(struct notifier_block *nb) {
> +	return atomic_notifier_chain_unregister(&beu_chain, nb); }
> +
> +static irqreturn_t beu_sifive_irq(int irq, void *data) {
> +	struct beu_sifive_ddata *ddata = data;
> +	unsigned char cause, addr;
> +
> +	addr = readb(ddata->regs + SIFIVE_BEU_VALUE);
> +	cause = readb(ddata->regs + SIFIVE_BEU_CAUSE);
> +	switch (cause) {
> +	case NO_ERR:
> +		break;
> +	case ITIM_CORR_ECC:
> +		pr_err("BEU: ITIM ECCFIX @ %d\n", addr);
> +		atomic_notifier_call_chain(&beu_chain,
> SIFIVE_BEU_ERR_TYPE_CE,
> +					   "ITIM ECCFIX");
> +		break;
> +	case ITIM_UNCORR_ECC:
> +		pr_err("BEU: ITIM ECCFAIL @ %d\n", addr);
> +		atomic_notifier_call_chain(&beu_chain,
> SIFIVE_BEU_ERR_TYPE_UE,
> +					   "ITIM ECCFAIL");
> +		break;
> +	case TILINKBUS_ERR:
> +		pr_err("BEU: Load or Store TILINK BUS ERR occurred\n");
> +		break;
> +	case DCACHE_CORR_ECC:
> +		pr_err("BEU: DATACACHE ECCFIX @ %d\n", addr);
> +		atomic_notifier_call_chain(&beu_chain,
> SIFIVE_BEU_ERR_TYPE_CE,
> +					   "DCACHE ECCFIX");
> +		break;
> +	case DCACHE_UNCORR_ECC:
> +		pr_err("BEU: DATACACHE ECCFAIL @ %d\n", addr);
> +		atomic_notifier_call_chain(&beu_chain,
> SIFIVE_BEU_ERR_TYPE_UE,
> +					   "DCACHE ECCFAIL");
> +		break;
> +	default:
> +		pr_err("BEU: Unidentified cause\n");
> +		break;
> +	}
> +	writeb(0, ddata->regs + SIFIVE_BEU_CAUSE);
> +	writeb(0, ddata->regs + SIFIVE_BEU_ACCRUED);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int beu_sifive_probe(struct platform_device *pdev) {
> +	struct device *dev = &pdev->dev;
> +	struct beu_sifive_ddata *ddata;
> +	struct resource *res;
> +	int ret, i;
> +
> +	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
> +	if (!ddata)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	ddata->regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(ddata->regs)) {
> +		dev_err(dev, "Unable to map IO resources\n");
> +		return PTR_ERR(ddata->regs);
> +	}
> +
> +	ddata->irq = platform_get_irq(pdev, 0);
> +	if (ddata->irq < 0) {
> +		dev_err(dev, "Unable to find interrupt\n");
> +		ret = ddata->irq;
> +		return ret;
> +	}
> +
> +	ret = devm_request_irq(dev, ddata->irq, beu_sifive_irq, 0,
> +			       dev_name(dev), ddata);
> +	if (ret) {
> +		dev_err(dev, "Unable to request IRQ\n");
> +		return ret;
> +	}
> +
> +	for (i = 0; i < MAX_ERR_EVENTS; i++) {
> +		ret = beu_enable_event(ddata, err_events[i],
> PLIC_INTERRUPT);
> +		if (ret) {
> +			dev_err(dev, "Unable to register PLIC interrupt\n");
> +			return ret;
> +		}
> +	}
> +
> +	platform_set_drvdata(pdev, ddata);
> +
> +	return 0;
> +}
> +
> +static int beu_sifive_remove(struct platform_device *pdev) {
> +	struct beu_sifive_ddata *ddata = platform_get_drvdata(pdev);
> +
> +	/* Mask all error events */
> +	writeb(0, ddata->regs + SIFIVE_BEU_ENABLE);
> +	writeb(0, ddata->regs + SIFIVE_BEU_PLIC_INTR);
> +	writeb(0, ddata->regs + SIFIVE_BEU_LOCAL_INTR);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id beu_sifive_of_match[] = {
> +	{ .compatible = "sifive,beu0" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, beu_sifive_of_match);
> +
> +static struct platform_driver beu_sifive_driver = {
> +	.probe = beu_sifive_probe,
> +	.remove = beu_sifive_remove,
> +	.driver = {
> +		.name = "beu-sifive",
> +		.of_match_table = beu_sifive_of_match,
> +	},
> +};
> +module_platform_driver(beu_sifive_driver);
> +
> +MODULE_DESCRIPTION("SiFive BEU driver"); MODULE_LICENSE("GPL v2");
> diff --git a/include/soc/sifive/sifive_beu.h b/include/soc/sifive/sifive_beu.h
> new file mode 100644 index 0000000..c2ab688
> --- /dev/null
> +++ b/include/soc/sifive/sifive_beu.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * SiFive Bus Error unit header file
> + *
> + */
> +
> +#ifndef __SOC_SIFIVE_BEU_H
> +#define __SOC_SIFIVE_BEU_H
> +
> +extern int register_sifive_beu_error_notifier(struct notifier_block
> +*nb); extern int unregister_sifive_beu_error_notifier(struct
> +notifier_block *nb);
> +
> +#define SIFIVE_BEU_ERR_TYPE_CE 0
> +#define SIFIVE_BEU_ERR_TYPE_UE 1
> +
> +#endif /* __SOC_SIFIVE_BEU_H */
> --
> 2.7.4