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Subject: Re: [PATCH v9 1/3] edac: Add support for Amazon's Annapurna Labs L1
 EDAC
To:     Borislav Petkov <bp@alien8.de>
CC:     <mchehab@kernel.org>, <tony.luck@intel.com>, <james.morse@arm.com>,
        <rrichter@marvell.com>, <robh+dt@kernel.org>,
        <frowand.list@gmail.com>, <davem@davemloft.net>,
        <gregkh@linuxfoundation.org>, <Jonathan.Cameron@huawei.com>,
        <arnd@arndb.de>, <linux-kernel@vger.kernel.org>,
        <linux-edac@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <dwmw@amazon.co.uk>, <benh@amazon.com>, <ronenk@amazon.com>,
        <talel@amazon.com>, <jonnyc@amazon.com>, <hanochu@amazon.com>,
        <barakw@amazon.com>
References: <20200129195016.956-1-hhhawa@amazon.com>
 <20200129195016.956-2-hhhawa@amazon.com> <20200225185211.GB5457@zn.tnic>
From:   "Hawa, Hanna" <hhhawa@amazon.com>
Message-ID: <270c7bad-0d68-4496-c83f-f491c38b4992@amazon.com>
Date:   Wed, 4 Mar 2020 11:02:43 +0200
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On 2/25/2020 8:52 PM, Borislav Petkov wrote:
> On Wed, Jan 29, 2020 at 09:50:14PM +0200, Hanna Hawa wrote:
> 
>> Adds support for Amazon's Annapurna Labs L1 EDAC driver to detect and
>> report L1 errors.
> 
> You don't add support for a driver - you either add a driver or you add
> support for HW...
> 
>> diff --git a/drivers/edac/al_l1_edac.c b/drivers/edac/al_l1_edac.c
>> new file mode 100644
>> index 000000000000..723b35b18f5b
>> --- /dev/null
>> +++ b/drivers/edac/al_l1_edac.c
>> @@ -0,0 +1,207 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
>> + */
>> +
>> +#include <asm/sysreg.h>
>> +#include <linux/bitfield.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/smp.h>
> 
> asm/ includes go after linux/ includes.

Will be fixed

> 
>> +
>> +#include "edac_device.h"
>> +#include "edac_module.h"
>> +
>> +#define DRV_NAME				"al_l1_edac"
>> +
>> +/* 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		BIT(31)
>> +#define ARM_CA57_CPUMERRSR_REPEAT		GENMASK_ULL(39, 32)
>> +#define ARM_CA57_CPUMERRSR_OTHER		GENMASK_ULL(47, 40)
>> +#define ARM_CA57_CPUMERRSR_FATAL		BIT_ULL(63)
>> +
>> +#define AL_L1_EDAC_MSG_MAX			256
>> +
>> +static void al_l1_edac_cpumerrsr_read_status(void *arg)
> 
> This is a static function so you don't really need a function prefix of
> "al_l1_edac_". Use those chars to make its name more descriptive. Ditto
> for the rest of the static functions in that file.

Will be fixed.

> 
>> +{
>> +	struct edac_device_ctl_info *edac_dev = arg;
>> +	int cpu, space, count;
>> +	u32 ramid, repeat, other, fatal;
>> +	u64 val;
>> +	char msg[AL_L1_EDAC_MSG_MAX];
>> +	char *p;
>> +	spinlock_t *lock;
> 
> Please sort function local variables declaration in a reverse christmas
> tree order:
> 
> 	<type A> longest_variable_name;
> 	<type B> shorter_var_name;
> 	<type C> even_shorter;
> 	<type D> i;

Will be fixed

> 
>> +
>> +	val = read_sysreg_s(ARM_CA57_CPUMERRSR_EL1);
>> +	if (!(FIELD_GET(ARM_CA57_CPUMERRSR_VALID, val)))
>> +		return;
>> +
>> +	write_sysreg_s(0, ARM_CA57_CPUMERRSR_EL1);
>> +
>> +	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 = scnprintf(p, space, "CPU%d L1 %serror detected", cpu,
>> +			  (fatal) ? "Fatal " : "");
>> +	p += count;
>> +	space -= count;
>> +
>> +	switch (ramid) {
>> +	case ARM_CA57_L1_I_TAG_RAM:
>> +		count = scnprintf(p, space, " RAMID='L1-I Tag RAM'");
>> +		break;
>> +	case ARM_CA57_L1_I_DATA_RAM:
>> +		count = scnprintf(p, space, " RAMID='L1-I Data RAM'");
>> +		break;
>> +	case ARM_CA57_L1_D_TAG_RAM:
>> +		count = scnprintf(p, space, " RAMID='L1-D Tag RAM'");
>> +		break;
>> +	case ARM_CA57_L1_D_DATA_RAM:
>> +		count = scnprintf(p, space, " RAMID='L1-D Data RAM'");
>> +		break;
>> +	case ARM_CA57_L2_TLB_RAM:
>> +		count = scnprintf(p, space, " RAMID='L2 TLB RAM'");
>> +		break;
>> +	default:
>> +		count = scnprintf(p, space, " RAMID='unknown'");
>> +		break;
>> +	}
>> +
>> +	p += count;
>> +	space -= count;
>> +	count = scnprintf(p, space,
>> +			  " repeat=%d, other=%d (CPUMERRSR_EL1=0x%llx)",
>> +			  repeat, other, val);
>> +
>> +	lock = edac_dev->pvt_info;
> 
> That sure looks funky - why not use a proper private struct like the
> rest of the drivers?

Then the structure will include single variable..

> 
>> +	spin_lock(lock);
>> +	if (fatal)
>> +		edac_device_handle_ue_count(edac_dev, repeat, 0, 0, msg);
>> +	else
>> +		edac_device_handle_ce_count(edac_dev, repeat, 0, 0, msg);
>> +	spin_unlock(lock);
>> +}
>> +
>> +static void al_l1_edac_check(struct edac_device_ctl_info *edac_dev)
>> +{
>> +	on_each_cpu(al_l1_edac_cpumerrsr_read_status, 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;
>> +	spinlock_t *lock;
>> +	int ret;
>> +
>> +	edac_dev = edac_device_alloc_ctl_info(sizeof(*lock), DRV_NAME, 1, "L",
>> +					      1, 1, NULL, 0,
>> +					      edac_device_alloc_index());
>> +	if (!edac_dev)
>> +		return -ENOMEM;
>> +
>> +	edac_dev->edac_check = al_l1_edac_check;
>> +	edac_dev->dev = dev;
>> +	edac_dev->mod_name = DRV_NAME;
>> +	edac_dev->dev_name = dev_name(dev);
>> +	edac_dev->ctl_name = "L1_cache";
>> +	platform_set_drvdata(pdev, edac_dev);
>> +	lock = edac_dev->pvt_info;
>> +
>> +	spin_lock_init(lock);
>> +
>> +	ret = edac_device_add_device(edac_dev);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to add L1 edac device (%d)\n", ret);
>> +		edac_device_free_ctl_info(edac_dev);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +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);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id al_l1_edac_of_match[] = {
>> +	/*
>> +	 * "al,alpine-v2", and "amazon,al-alpine-v3" are machine compatible
>> +	 * strings which have Cortex-A57/A72 configured with this support,
>> +	 * and access to CPUMERRSR_EL1 register is enabled in firmware.
>> +	 */
>> +	{ .compatible = "al,alpine-v2" },
> 
> Err, checkpatch says:
> 
> WARNING: DT compatible string "al,alpine-v2" appears un-documented -- check ./Documentation/devicetree/bindings/
> #236: FILE: drivers/edac/al_l1_edac.c:151:
> +       { .compatible = "al,alpine-v2" },
> 
> 
> Do you need a devicetree addition? I usually get such with the ARM EDAC
> drivers...

There is missing documentation for alpine-v2, there is an open patches 
to add this missing doc. [1]

[1]: https://lkml.org/lkml/2020/2/25/362

> 
>> +	{ .compatible = "amazon,al-alpine-v3" },
>> +	{}
>> +};
>> +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 = DRV_NAME,
>> +	},
>> +};
>> +
>> +static struct platform_device *edac_l1_device;
> 
> Please move to the top of the file.

Ack.

> 
>> +
>> +static int __init al_l1_init(void)
>> +{
>> +	struct device_node *root;
>> +	int ret;
>> +
>> +	root = of_find_node_by_path("/");
>> +	if (!root) {
>> +		pr_debug("Can't find root node!\n");
>> +		return 0;
>> +	}
>> +
>> +	if (!of_match_node(al_l1_edac_of_match, root))
>> +		return 0;
>> +
>> +	ret = platform_driver_register(&al_l1_edac_driver);
>> +	if (ret) {
>> +		pr_err("Failed to register %s (%d)\n", DRV_NAME, ret);
>> +		return ret;
>> +	}
>> +
>> +	edac_l1_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
>> +	if (IS_ERR(edac_l1_device)) {
>> +		pr_err("Failed to register EDAC AL L1 platform device\n");
> 
> 		platform_driver_unregister() ?

Ack

> 
>> +		return PTR_ERR(edac_l1_device);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static void __exit al_l1_exit(void)
>> +{
>> +	platform_device_unregister(edac_l1_device);
>> +	platform_driver_unregister(&al_l1_edac_driver);
>> +}
>> +
>> +late_initcall(al_l1_init);
> 
> Why not module_init() ?

Will be fixed.

Thanks,
Hanna
>