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Message-ID: <c4554f47-83e2-32d4-e30c-9610c35d9065@redhat.com>
Date:   Mon, 17 Apr 2023 10:17:37 +0200
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Subject: Re: [PATCH v1 1/1] mlxbf-bootctl: Add sysfs file for BlueField boot
 fifo
Content-Language: en-US, nl
To:     Liming Sun <limings@nvidia.com>,
        Vadim Pasternak <vadimp@nvidia.com>,
        David Thompson <davthompson@nvidia.com>,
        Mark Gross <markgross@kernel.org>
Cc:     platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
References: <52b0b00dacbc4aad3169dd3667d79c85e334783b.1680657571.git.limings@nvidia.com>
From:   Hans de Goede <hdegoede@redhat.com>
In-Reply-To: <52b0b00dacbc4aad3169dd3667d79c85e334783b.1680657571.git.limings@nvidia.com>
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Hi,

On 4/11/23 17:39, Liming Sun wrote:
> This commit adds sysfs file for BlueField boot fifo. The boot
> fifo is usually used to push boot stream via USB or PCIe. Once
> OS is up, it can be reused by applications to read data or
> configuration from external host.
> 
> Signed-off-by: Liming Sun <limings@nvidia.com>
> Reviewed-by: David Thompson <davthompson@nvidia.com>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans


> ---
>  .../testing/sysfs-platform-mellanox-bootctl   |  7 ++
>  drivers/platform/mellanox/mlxbf-bootctl.c     | 68 +++++++++++++++++++
>  2 files changed, 75 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl b/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> index e79ca22e2f45..9b99a81babb1 100644
> --- a/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> +++ b/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> @@ -68,3 +68,10 @@ Description:
>  		Wasted   burnt and invalid
>  		Invalid  not burnt but marked as valid (error state).
>  		=======  ===============================================
> +
> +What:		/sys/bus/platform/devices/MLNXBF04:00/bootfifo
> +Date:		Apr 2023
> +KernelVersion:	6.4
> +Contact:	"Liming Sun <limings@nvidia.com>"
> +Description:
> +		The file used to access the BlueField boot fifo.
> diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c b/drivers/platform/mellanox/mlxbf-bootctl.c
> index 1c7a288b59a5..d4463bb632e1 100644
> --- a/drivers/platform/mellanox/mlxbf-bootctl.c
> +++ b/drivers/platform/mellanox/mlxbf-bootctl.c
> @@ -10,6 +10,7 @@
>  
>  #include <linux/acpi.h>
>  #include <linux/arm-smccc.h>
> +#include <linux/delay.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
>  
> @@ -44,6 +45,10 @@ static const char * const mlxbf_bootctl_lifecycle_states[] = {
>  	[3] = "RMA",
>  };
>  
> +/* Mapped pointer for RSH_BOOT_FIFO_DATA and RSH_BOOT_FIFO_COUNT register. */
> +static void __iomem *mlxbf_rsh_boot_data;
> +static void __iomem *mlxbf_rsh_boot_cnt;
> +
>  /* ARM SMC call which is atomic and no need for lock. */
>  static int mlxbf_bootctl_smc(unsigned int smc_op, int smc_arg)
>  {
> @@ -268,6 +273,45 @@ static const struct acpi_device_id mlxbf_bootctl_acpi_ids[] = {
>  
>  MODULE_DEVICE_TABLE(acpi, mlxbf_bootctl_acpi_ids);
>  
> +static ssize_t mlxbf_bootctl_bootfifo_read(struct file *filp,
> +					   struct kobject *kobj,
> +					   struct bin_attribute *bin_attr,
> +					   char *buf, loff_t pos,
> +					   size_t count)
> +{
> +	unsigned long timeout = msecs_to_jiffies(500);
> +	unsigned long expire = jiffies + timeout;
> +	u64 data, cnt = 0;
> +	char *p = buf;
> +
> +	while (count >= sizeof(data)) {
> +		/* Give up reading if no more data within 500ms. */
> +		if (!cnt) {
> +			cnt = readq(mlxbf_rsh_boot_cnt);
> +			if (!cnt) {
> +				if (time_after(jiffies, expire))
> +					break;
> +				usleep_range(10, 50);
> +				continue;
> +			}
> +		}
> +
> +		data = readq(mlxbf_rsh_boot_data);
> +		memcpy(p, &data, sizeof(data));
> +		count -= sizeof(data);
> +		p += sizeof(data);
> +		cnt--;
> +		expire = jiffies + timeout;
> +	}
> +
> +	return p - buf;
> +}
> +
> +static struct bin_attribute mlxbf_bootctl_bootfifo_sysfs_attr = {
> +	.attr = { .name = "bootfifo", .mode = 0400 },
> +	.read = mlxbf_bootctl_bootfifo_read,
> +};
> +
>  static bool mlxbf_bootctl_guid_match(const guid_t *guid,
>  				     const struct arm_smccc_res *res)
>  {
> @@ -285,6 +329,16 @@ static int mlxbf_bootctl_probe(struct platform_device *pdev)
>  	guid_t guid;
>  	int ret;
>  
> +	/* Get the resource of the bootfifo data register. */
> +	mlxbf_rsh_boot_data = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(mlxbf_rsh_boot_data))
> +		return PTR_ERR(mlxbf_rsh_boot_data);
> +
> +	/* Get the resource of the bootfifo counter register. */
> +	mlxbf_rsh_boot_cnt = devm_platform_ioremap_resource(pdev, 1);
> +	if (IS_ERR(mlxbf_rsh_boot_cnt))
> +		return PTR_ERR(mlxbf_rsh_boot_cnt);
> +
>  	/* Ensure we have the UUID we expect for this service. */
>  	arm_smccc_smc(MLXBF_BOOTCTL_SIP_SVC_UID, 0, 0, 0, 0, 0, 0, 0, &res);
>  	guid_parse(mlxbf_bootctl_svc_uuid_str, &guid);
> @@ -302,11 +356,25 @@ static int mlxbf_bootctl_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		dev_warn(&pdev->dev, "Unable to reset the EMMC boot mode\n");
>  
> +	ret = sysfs_create_bin_file(&pdev->dev.kobj,
> +				    &mlxbf_bootctl_bootfifo_sysfs_attr);
> +	if (ret)
> +		pr_err("Unable to create bootfifo sysfs file, error %d\n", ret);
> +
> +	return ret;
> +}
> +
> +static int mlxbf_bootctl_remove(struct platform_device *pdev)
> +{
> +	sysfs_remove_bin_file(&pdev->dev.kobj,
> +			      &mlxbf_bootctl_bootfifo_sysfs_attr);
> +
>  	return 0;
>  }
>  
>  static struct platform_driver mlxbf_bootctl_driver = {
>  	.probe = mlxbf_bootctl_probe,
> +	.remove = mlxbf_bootctl_remove,
>  	.driver = {
>  		.name = "mlxbf-bootctl",
>  		.dev_groups = mlxbf_bootctl_groups,