lkml.org 
[lkml]   [2020]   [Jan]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v7 1/3] edac: Add support for Amazon's Annapurna Labs L1 EDAC
From
Date
Hi Hanna,

(This was still on my list. I've not seen a newer version, its not in next, and it still
applies, so:)

On 15/10/2019 13:09, Hanna Hawa wrote:
> Adds support for Amazon's Annapurna Labs L1 EDAC driver to detect and
> report L1 errors.

> diff --git a/drivers/edac/al_l1_edac.c b/drivers/edac/al_l1_edac.c
> new file mode 100644
> index 000000000000..e363a80b4d13
> --- /dev/null
> +++ b/drivers/edac/al_l1_edac.c
> @@ -0,0 +1,190 @@

> +#include <asm/sysreg.h>
> +#include <linux/bitfield.h>
> +#include <linux/of.h>
> +#include <linux/smp.h>

You need <linux/platform_device.h> for platform_device_register_simple().

[...]

> +static void al_l1_edac_cpumerrsr_read_status(void *arg)
> +{

> + 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);
> + }

What serialises these? You kick this off from on_each_cpu(), what stops two CPUs calling
this at the same time? 'edac_dev->counters.ce_count += count;' will go wrong in this case.

I think you need a spinlock around the edac_device_* calls that take edac_dev so that only
one occurs at a time.


> +}
> +
> +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;
> + int ret;
> +
> + edac_dev = edac_device_alloc_ctl_info(0, 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);
> +
> + ret = edac_device_add_device(edac_dev);
> + if (ret)
> + goto err;
> +
> + return 0;
> +err:

(this goto has one user, meaning you can remove it by restructuring the code)


> + dev_err(dev, "Failed to add L1 edac device (%d)\n", ret);
> + edac_device_free_ctl_info(edac_dev);
> +
> + return ret;
> +}
> +

> +static const struct of_device_id al_l1_edac_of_match[] = {
> + { .compatible = "al,alpine-v2" },
> + { .compatible = "amazon,alpine-v3" },
> + {}
> +};

Unusually these are machine compatibles. It may be worth a comment that these are the
platforms which are known to have Cortex-A57/A72 configured with this support, and access
to the registers enabled by firmware.


> +MODULE_DEVICE_TABLE(of, al_l1_edac_of_match);

[..]

> +static int __init al_l1_init(void)
> +{
> + struct device_node *root = of_find_node_by_path("/");
> + int ret;

root could be NULL here.


> + 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");
> + return PTR_ERR(edac_l1_device);
> + }
> +
> + return 0;
> +}

With the edac_device_handle_ce() race fixed:
Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

\
 
 \ /
  Last update: 2020-01-15 19:50    [W:0.079 / U:149.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site