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Date:   Tue, 9 Jul 2019 17:32:29 +0800
From:   Jonathan Cameron <Jonathan.Cameron@huawei.com>
To:     Hanna Hawa <hhhawa@amazon.com>
CC:     <robh+dt@kernel.org>, <mark.rutland@arm.com>, <bp@alien8.de>,
        <mchehab@kernel.org>, <james.morse@arm.com>, <davem@davemloft.net>,
        <gregkh@linuxfoundation.org>, <linus.walleij@linaro.org>,
        <nicolas.ferre@microchip.com>, <paulmck@linux.ibm.com>,
        <dwmw@amazon.co.uk>, <benh@amazon.com>, <ronenk@amazon.com>,
        <talel@amazon.com>, <jonnyc@amazon.com>, <hanochu@amazon.com>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-edac@vger.kernel.org>
Subject: Re: [PATCH v2 2/4] edac: Add support for Amazon's Annapurna Labs L1
 EDAC
Message-ID: <20190709173229.0000135f@huawei.com>
In-Reply-To: <1562500658-14717-3-git-send-email-hhhawa@amazon.com>
References: <1562500658-14717-1-git-send-email-hhhawa@amazon.com>
        <1562500658-14717-3-git-send-email-hhhawa@amazon.com>
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On Sun, 7 Jul 2019 14:57:36 +0300
Hanna Hawa <hhhawa@amazon.com> wrote:

> Adds support for Amazon's Annapurna Labs L1 EDAC driver to detect and
> report L1 errors.
> 
> Signed-off-by: Hanna Hawa <hhhawa@amazon.com>
A quick drive by review as I was feeling curious.

Just a couple of trivial queries and observation on the fact it
might be useful to add a few devm managed functions to cut down
on edac driver boilerplate.

Thanks,

Jonathan

> ---
>  MAINTAINERS               |   6 ++
>  drivers/edac/Kconfig      |   8 +++
>  drivers/edac/Makefile     |   1 +
>  drivers/edac/al_l1_edac.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 169 insertions(+)
>  create mode 100644 drivers/edac/al_l1_edac.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 77eae44..fd29ea6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -743,6 +743,12 @@ F:	drivers/tty/serial/altera_jtaguart.c
>  F:	include/linux/altera_uart.h
>  F:	include/linux/altera_jtaguart.h
>  
> +AMAZON ANNAPURNA LABS L1 EDAC
> +M:	Hanna Hawa <hhhawa@amazon.com>
> +S:	Maintained
> +F:	drivers/edac/al_l1_edac.c
> +F:	Documentation/devicetree/bindings/edac/amazon,al-l1-edac.txt
> +
>  AMAZON ANNAPURNA LABS THERMAL MMIO DRIVER
>  M:	Talel Shenhar <talel@amazon.com>
>  S:	Maintained
> diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
> index 200c04c..58b92bc 100644
> --- a/drivers/edac/Kconfig
> +++ b/drivers/edac/Kconfig
> @@ -74,6 +74,14 @@ config EDAC_GHES
>  
>  	  In doubt, say 'Y'.
>  
> +config EDAC_AL_L1
> +	bool "Amazon's Annapurna Labs L1 EDAC"
> +	depends on ARCH_ALPINE
> +	help
> +	  Support for L1 error detection and correction
> +	  for Amazon's Annapurna Labs SoCs.
> +	  This driver detects errors of L1 caches.
> +
>  config EDAC_AMD64
>  	tristate "AMD64 (Opteron, Athlon64)"
>  	depends on AMD_NB && EDAC_DECODE_MCE
> diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
> index 165ca65e..caa2dc9 100644
> --- a/drivers/edac/Makefile
> +++ b/drivers/edac/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_EDAC_GHES)			+= ghes_edac.o
>  edac_mce_amd-y				:= mce_amd.o
>  obj-$(CONFIG_EDAC_DECODE_MCE)		+= edac_mce_amd.o
>  
> +obj-$(CONFIG_EDAC_AL_L1)		+= al_l1_edac.o
>  obj-$(CONFIG_EDAC_AMD76X)		+= amd76x_edac.o
>  obj-$(CONFIG_EDAC_CPC925)		+= cpc925_edac.o
>  obj-$(CONFIG_EDAC_I5000)		+= i5000_edac.o
> diff --git a/drivers/edac/al_l1_edac.c b/drivers/edac/al_l1_edac.c
> new file mode 100644
> index 0000000..f51a6c3
> --- /dev/null
> +++ b/drivers/edac/al_l1_edac.c
> @@ -0,0 +1,154 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
> + */
> +
> +#include <linux/bitfield.h>
> +
> +#include "edac_device.h"
> +#include "edac_module.h"
> +
> +/* Same bit assignments of CPUMERRSR_EL1 in ARM CA57/CA72 */
> +#define ARM_CA57_CPUMERRSR_EL1			sys_reg(3, 1, 15, 2, 2)
> +#define ARM_CA57_CPUMERRSR_RAM_ID		GENMASK(30, 24)
> +#define  ARM_CA57_L1_I_TAG_RAM			0x00
> +#define  ARM_CA57_L1_I_DATA_RAM			0x01
> +#define  ARM_CA57_L1_D_TAG_RAM			0x08
> +#define  ARM_CA57_L1_D_DATA_RAM			0x09
> +#define  ARM_CA57_L2_TLB_RAM			0x18
> +#define ARM_CA57_CPUMERRSR_VALID		GENMASK(31, 31)

For a single bit it's common to use BIT(31) rather than GENMASK to make
it explicit.


> +#define ARM_CA57_CPUMERRSR_REPEAT		GENMASK(39, 32)
> +#define ARM_CA57_CPUMERRSR_OTHER		GENMASK(47, 40)
> +#define ARM_CA57_CPUMERRSR_FATAL		GENMASK(63, 63)
> +
> +#define AL_L1_EDAC_MSG_MAX			256
> +
> +static void al_l1_edac_cpumerrsr(void *arg)
> +{
> +	struct edac_device_ctl_info *edac_dev = arg;
> +	int cpu, i;
> +	u32 ramid, repeat, other, fatal;
> +	u64 val = read_sysreg_s(ARM_CA57_CPUMERRSR_EL1);
> +	char msg[AL_L1_EDAC_MSG_MAX];
> +	int space, count;
> +	char *p;
> +
> +	if (!(FIELD_GET(ARM_CA57_CPUMERRSR_VALID, val)))
> +		return;
> +
> +	cpu = smp_processor_id();
> +	ramid = FIELD_GET(ARM_CA57_CPUMERRSR_RAM_ID, val);
> +	repeat = FIELD_GET(ARM_CA57_CPUMERRSR_REPEAT, val);
> +	other = FIELD_GET(ARM_CA57_CPUMERRSR_OTHER, val);
> +	fatal = FIELD_GET(ARM_CA57_CPUMERRSR_FATAL, val);
> +
> +	space = sizeof(msg);
> +	p = msg;
> +	count = snprintf(p, space, "CPU%d L1 %serror detected", cpu,
> +			 (fatal) ? "Fatal " : "");
> +	p += count;
> +	space -= count;
> +
> +	switch (ramid) {
> +	case ARM_CA57_L1_I_TAG_RAM:
> +		count = snprintf(p, space, " RAMID='L1-I Tag RAM'");
> +		break;
> +	case ARM_CA57_L1_I_DATA_RAM:
> +		count = snprintf(p, space, " RAMID='L1-I Data RAM'");
> +		break;
> +	case ARM_CA57_L1_D_TAG_RAM:
> +		count = snprintf(p, space, " RAMID='L1-D Tag RAM'");
> +		break;
> +	case ARM_CA57_L1_D_DATA_RAM:
> +		count = snprintf(p, space, " RAMID='L1-D Data RAM'");
> +		break;
> +	case ARM_CA57_L2_TLB_RAM:
> +		count = snprintf(p, space, " RAMID='L2 TLB RAM'");
> +		break;
> +	default:
> +		count = snprintf(p, space, " RAMID='unknown'");
> +		break;
> +	}
> +
> +	p += count;
> +	space -= count;
> +	count = snprintf(p, space,
> +			 " repeat=%d, other=%d (CPUMERRSR_EL1=0x%llx)",
> +			 repeat, other, val);
> +
> +	for (i = 0; i < repeat; i++) {
> +		if (fatal)
> +			edac_device_handle_ue(edac_dev, 0, 0, msg);
> +		else
> +			edac_device_handle_ce(edac_dev, 0, 0, msg);
> +	}
> +
> +	write_sysreg_s(0, ARM_CA57_CPUMERRSR_EL1);
> +}
> +
> +static void al_l1_edac_check(struct edac_device_ctl_info *edac_dev)
> +{
> +	on_each_cpu(al_l1_edac_cpumerrsr, edac_dev, 1);
> +}
> +
> +static int al_l1_edac_probe(struct platform_device *pdev)
> +{
> +	struct edac_device_ctl_info *edac_dev;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	edac_dev = edac_device_alloc_ctl_info(0, (char *)dev_name(dev), 1, "L",
> +					      1, 1, NULL, 0,
> +					      edac_device_alloc_index());
> +	if (IS_ERR(edac_dev))
> +		return -ENOMEM;
> +
> +	edac_dev->edac_check = al_l1_edac_check;
> +	edac_dev->dev = dev;
> +	edac_dev->mod_name = dev_name(dev);

I'd admit I'm not that familiar with edac, but seems odd that a
module name field would have the dev_name. 

> +	edac_dev->dev_name = dev_name(dev);
> +	edac_dev->ctl_name = dev_name(dev);
> +	platform_set_drvdata(pdev, edac_dev);
> +
> +	ret = edac_device_add_device(edac_dev);
> +	if (ret) {
> +		dev_err(dev, "Failed to add L1 edac device\n");
> +		goto err;
> +	}
> +
> +	return 0;
> +err:
> +	edac_device_free_ctl_info(edac_dev);
> +
> +	return ret;
> +}
> +
> +static int al_l1_edac_remove(struct platform_device *pdev)
> +{
> +	struct edac_device_ctl_info *edac_dev = platform_get_drvdata(pdev);
> +
> +	edac_device_del_device(edac_dev->dev);
> +	edac_device_free_ctl_info(edac_dev);

More a passing observation than a suggestion for this driver, but if there was
ever a place where it looked like a couple of devm_ allocation functions would
be useful, this is it ;)

edac_dev = devm_device_alloc_ctrl_info(dev, ...)
...
devm_edac_device_add_device(dev, ...)


> +
> +	return 0;
> +}
> +
> +static const struct of_device_id al_l1_edac_of_match[] = {
> +	{ .compatible = "amazon,al-l1-edac" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, al_l1_edac_of_match);
> +
> +static struct platform_driver al_l1_edac_driver = {
> +	.probe = al_l1_edac_probe,
> +	.remove = al_l1_edac_remove,
> +	.driver = {
> +		.name = "al_l1_edac",
> +		.of_match_table = al_l1_edac_of_match,
> +	},
> +};
> +module_platform_driver(al_l1_edac_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Hanna Hawa <hhhawa@amazon.com>");
> +MODULE_DESCRIPTION("Amazon's Annapurna Lab's L1 EDAC Driver");