linux-kernel - RE: [PATCH v1 1/2] mlxbf-bootctl: Support the large icmc write/read

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Date:   Wed, 9 Aug 2023 14:33:55 +0000
From:   Vadim Pasternak <vadimp@...dia.com>
To:     Asmaa Mnebhi <asmaa@...dia.com>,
        "markgross@...nel.org" <markgross@...nel.org>,
        "hdegoede@...hat.com" <hdegoede@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v1 1/2] mlxbf-bootctl: Support the large icmc write/read



> -----Original Message-----
> From: Asmaa Mnebhi <asmaa@...dia.com>
> Sent: Wednesday, 9 August 2023 17:15
> To: markgross@...nel.org; Vadim Pasternak <vadimp@...dia.com>;
> hdegoede@...hat.com; linux-kernel@...r.kernel.org
> Cc: Asmaa Mnebhi <asmaa@...dia.com>
> Subject: [PATCH v1 1/2] mlxbf-bootctl: Support the large icmc write/read
> 
> Enable reading and writing the size of the memory region associated with the
> large ICM carveout.
> The max size of the large ICM carveout is 1TB, has a granularity of 128MB and
> will be passed and printed in hex. The size unit is MB.
> 
> Signed-off-by: Asmaa Mnebhi <asmaa@...dia.com>
> ---
>  drivers/platform/mellanox/mlxbf-bootctl.c | 42 +++++++++++++++++++++++
> drivers/platform/mellanox/mlxbf-bootctl.h |  9 +++++
>  2 files changed, 51 insertions(+)
> 
> diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c
> b/drivers/platform/mellanox/mlxbf-bootctl.c
> index fb9f7815c6cd..3ea11250b681 100644
> --- a/drivers/platform/mellanox/mlxbf-bootctl.c
> +++ b/drivers/platform/mellanox/mlxbf-bootctl.c
> @@ -79,6 +79,8 @@ static void __iomem *mlxbf_rsh_scratch_buf_data;
> static const char * const mlxbf_rsh_log_level[] = {
>  	"INFO", "WARN", "ERR", "ASSERT"};
> 
> +static DEFINE_MUTEX(icm_ops_lock);
> +
>  /* ARM SMC call which is atomic and no need for lock. */  static int
> mlxbf_bootctl_smc(unsigned int smc_op, int smc_arg)  { @@ -391,6 +393,44
> @@ static ssize_t rsh_log_store(struct device *dev,
>  	return count;
>  }
> 
> +static ssize_t large_icm_show(struct device *dev,
> +				struct device_attribute *attr, char *buf) {
> +	struct arm_smccc_res res;
> +
> +	mutex_lock(&icm_ops_lock);
> +	arm_smccc_smc(MLNX_HANDLE_GET_ICM_INFO, 0, 0, 0, 0,
> +		      0, 0, 0, &res);
> +	mutex_unlock(&icm_ops_lock);
> +	if (res.a0)
> +		return -EPERM;
> +
> +	return snprintf(buf, PAGE_SIZE, "0x%lx", res.a1); }
> +
> +static ssize_t large_icm_store(struct device *dev,
> +			       struct device_attribute *attr,
> +			       const char *buf, size_t count) {
> +	struct arm_smccc_res res;
> +	unsigned long icm_data;
> +	int err;
> +
> +	err = kstrtoul(buf, 16, &icm_data);
> +	if (err)
> +		return err;

I suggest using define instead of 16.

> +
> +	if (((icm_data != 0) && (icm_data < 0x80)) ||
> +	    (icm_data > 0x100000) || (icm_data % 128))
> +		return -EPERM;

You can remove reduce '()' and I suggest for to use for consistency 128:
Instead of 128 and 0x80
	If ((icm_data > 0 && icm_data < 128)

Probably consider to use defines also for the above magic.

> +
> +	mutex_lock(&icm_ops_lock);
> +	arm_smccc_smc(MLNX_HANDLE_SET_ICM_INFO, icm_data, 0, 0, 0,
> 0, 0, 0, &res);
> +	mutex_unlock(&icm_ops_lock);
> +
> +	return res.a0 ? -EPERM : count;
> +}
> +
>  static DEVICE_ATTR_RW(post_reset_wdog);  static
> DEVICE_ATTR_RW(reset_action);  static
> DEVICE_ATTR_RW(second_reset_action);
> @@ -398,6 +438,7 @@ static DEVICE_ATTR_RO(lifecycle_state);  static
> DEVICE_ATTR_RO(secure_boot_fuse_state);
>  static DEVICE_ATTR_WO(fw_reset);
>  static DEVICE_ATTR_WO(rsh_log);
> +static DEVICE_ATTR_RW(large_icm);
> 
>  static struct attribute *mlxbf_bootctl_attrs[] = {
>  	&dev_attr_post_reset_wdog.attr,
> @@ -407,6 +448,7 @@ static struct attribute *mlxbf_bootctl_attrs[] = {
>  	&dev_attr_secure_boot_fuse_state.attr,
>  	&dev_attr_fw_reset.attr,
>  	&dev_attr_rsh_log.attr,
> +	&dev_attr_large_icm.attr,
>  	NULL
>  };
> 
> diff --git a/drivers/platform/mellanox/mlxbf-bootctl.h
> b/drivers/platform/mellanox/mlxbf-bootctl.h
> index b48243f60a59..75d59ade92be 100644
> --- a/drivers/platform/mellanox/mlxbf-bootctl.h
> +++ b/drivers/platform/mellanox/mlxbf-bootctl.h
> @@ -81,6 +81,15 @@
>   */
>  #define MLXBF_BOOTCTL_FW_RESET  0x8200000D
> 
> +/*
> + * SMC function IDs to set and get the large ICM carveout size
> + * stored in the eeprom.
> + */
> +#define MLNX_HANDLE_SET_ICM_INFO    0x82000012
> +#define MLNX_HANDLE_GET_ICM_INFO    0x82000013
> +
> +#define MAX_ICM_BUFFER_SIZE 10
> +
>  /* SMC function IDs for SiP Service queries */
>  #define MLXBF_BOOTCTL_SIP_SVC_CALL_COUNT	0x8200ff00
>  #define MLXBF_BOOTCTL_SIP_SVC_UID		0x8200ff01
> --
> 2.30.1