> -----Original Message-----
> From: Liming Sun <limings@xxxxxxxxxx>
> Sent: Wednesday, May 10, 2023 7:55 AM
> To: Vadim Pasternak <vadimp@xxxxxxxxxx>; David Thompson
> <davthompson@xxxxxxxxxx>; Hans de Goede <hdegoede@xxxxxxxxxx>; Mark
> Gross <markgross@xxxxxxxxxx>
> Cc: Liming Sun <limings@xxxxxxxxxx>; platform-driver-x86@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH v2] mlxbf-bootctl: Add sysfs file for BlueField boot log
>
> This commit adds sysfs interface to be used to write into the boot log which is 1KB
> HW buffer on BlueField SoC. The same log buffer is also used by firmware code
> like ATF/UEFI, and can be displayed by userspace tools or from external host via
> USB/PCIe.
>
> Signed-off-by: Liming Sun <limings@xxxxxxxxxx>
> Reviewed-by: Vadim Pasternak <vadimp@xxxxxxxxxx>
> ---
> v1->v2:
> Fixes for comments from Hans:
> - Add more details in Documentation about the log levels;
> - Replace 0x0a with '\n';
> - Solve comment 'Why len + 1, this seems intended to assume some
> separator between prefix'. The change is to remove the '+ 1'
> here to avoid confusion. Yes, it's trying to remove the space
> separator. Since the next block 'Ignore leading spaces' already
> has similar logic, no need for the '+ 1" here.
> v1: Initial version.
> ---
> .../testing/sysfs-platform-mellanox-bootctl | 9 ++
> drivers/platform/mellanox/mlxbf-bootctl.c | 141 ++++++++++++++++++
> 2 files changed, 150 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> b/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> index 9b99a81babb1..4c5c02d8f870 100644
> --- a/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> +++ b/Documentation/ABI/testing/sysfs-platform-mellanox-bootctl
> @@ -75,3 +75,12 @@ KernelVersion: 6.4
> Contact: "Liming Sun <limings@xxxxxxxxxx>"
> Description:
> The file used to access the BlueField boot fifo.
> +
> +What: /sys/bus/platform/devices/MLNXBF04:00/rsh_log
> +Date: May 2023
> +KernelVersion: 6.4
> +Contact: "Liming Sun <limings@xxxxxxxxxx>"
> +Description:
> + The file used to write BlueField boot log with the format
> + "[INFO|WARN|ERR|ASSERT ]<msg>". Log level 'INFO' is used by
> + default if not specified.
> diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c
> b/drivers/platform/mellanox/mlxbf-bootctl.c
> index 1bad1d278672..e88ce68acb89 100644
> --- a/drivers/platform/mellanox/mlxbf-bootctl.c
> +++ b/drivers/platform/mellanox/mlxbf-bootctl.c
> @@ -45,10 +45,38 @@ static const char * const mlxbf_bootctl_lifecycle_states[]
> = {
> [3] = "RMA",
> };
>
> +/* Log header format. */
> +#define MLXBF_RSH_LOG_TYPE_SHIFT 56
> +#define MLXBF_RSH_LOG_LEN_SHIFT 48
> +#define MLXBF_RSH_LOG_LEVEL_SHIFT 0
> +
> +/* Log module ID and type (only MSG type in Linux driver for now). */
> +#define MLXBF_RSH_LOG_TYPE_MSG 0x04ULL
> +
> +/* Log ctl/data register offset. */
> +#define MLXBF_RSH_SCRATCH_BUF_CTL_OFF 0
> +#define MLXBF_RSH_SCRATCH_BUF_DATA_OFF 0x10
> +
> +/* Log message levels. */
> +enum {
> + MLXBF_RSH_LOG_INFO,
> + MLXBF_RSH_LOG_WARN,
> + MLXBF_RSH_LOG_ERR
> +};
> +
Should add "MLXBF_RSH_LOG_ASSERT" to enum for completeness
> /* 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;
>
> +/* Mapped pointer for rsh log semaphore/ctrl/data register. */ static
> +void __iomem *mlxbf_rsh_semaphore; static void __iomem
> +*mlxbf_rsh_scratch_buf_ctl; static void __iomem
> +*mlxbf_rsh_scratch_buf_data;
> +
> +/* Rsh log levels. */
> +static const char * const mlxbf_rsh_log_level[] = {
> + "INFO", "WARN", "ERR", "ASSERT"};
> +
> /* ARM SMC call which is atomic and no need for lock. */ static int
> mlxbf_bootctl_smc(unsigned int smc_op, int smc_arg) { @@ -266,12 +294,111
> @@ static ssize_t fw_reset_store(struct device *dev,
> return count;
> }
>
> +/* Size(8-byte words) of the log buffer. */
> +#define RSH_SCRATCH_BUF_CTL_IDX_MASK 0x7f
> +
> +static int mlxbf_rsh_log_sem_lock(void) {
> + unsigned long timeout;
> +
> + /* Take the semaphore. */
> + timeout = jiffies + msecs_to_jiffies(100);
> + while (readq(mlxbf_rsh_semaphore)) {
> + if (time_after(jiffies, timeout))
> + return -ETIMEDOUT;
> + }
> +
> + return 0;
> +}
> +
> +static void mlxbf_rsh_log_sem_unlock(void) {
> + writeq(0, mlxbf_rsh_semaphore);
> +}
> +
> +static ssize_t rsh_log_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + int rc, idx, num, len, size = (int)count, level = MLXBF_RSH_LOG_INFO;
> + u64 data;
> +
> + if (!size)
> + return -EINVAL;
> +
> + if (!mlxbf_rsh_semaphore || !mlxbf_rsh_scratch_buf_ctl)
> + return -EOPNOTSUPP;
> +
> + /* Ignore line break at the end. */
> + if (buf[size - 1] == '\n')
> + size--;
> +
> + /* Check the message prefix. */
> + for (idx = 0; idx < ARRAY_SIZE(mlxbf_rsh_log_level); idx++) {
> + len = strlen(mlxbf_rsh_log_level[idx]);
> + if (len + 1 < size &&
> + !strncmp(buf, mlxbf_rsh_log_level[idx], len)) {
> + buf += len;
> + size -= len;
> + level = idx;
> + break;
> + }
> + }
> +
> + /* Ignore leading spaces. */
> + while (size > 0 && buf[0] == ' ') {
> + size--;
> + buf++;
> + }
> +
> + /* Take the semaphore. */
> + rc = mlxbf_rsh_log_sem_lock();
> + if (rc)
> + return rc;
> +
> + /* Calculate how many words are available. */
> + num = (size + sizeof(u64) - 1) / sizeof(u64);
> + idx = readq(mlxbf_rsh_scratch_buf_ctl);
> + if (idx + num + 1 >= RSH_SCRATCH_BUF_CTL_IDX_MASK)
> + num = RSH_SCRATCH_BUF_CTL_IDX_MASK - idx - 1;
> + if (num <= 0)
> + goto done;
> +
> + /* Write Header. */
> + data = (MLXBF_RSH_LOG_TYPE_MSG << MLXBF_RSH_LOG_TYPE_SHIFT)
> |
> + ((u64)num << MLXBF_RSH_LOG_LEN_SHIFT) |
> + ((u64)level << MLXBF_RSH_LOG_LEVEL_SHIFT);
Should use FIELD_PREP() macro to generate value in "data"
> + writeq(data, mlxbf_rsh_scratch_buf_data);
> +
> + /* Write message. */
> + for (idx = 0, len = size; idx < num && len > 0; idx++) {
> + if (len <= sizeof(u64)) {
> + data = 0;
> + memcpy(&data, buf, len);
> + len = 0;
> + } else {
> + memcpy(&data, buf, sizeof(u64));
> + len -= sizeof(u64);
> + buf += sizeof(u64);
> + }
> + writeq(data, mlxbf_rsh_scratch_buf_data);
> + }
> +
> +done:
> + /* Release the semaphore. */
> + mlxbf_rsh_log_sem_unlock();
> +
> + /* Ignore the rest if no more space. */
> + return count;
> +}
> +
> static DEVICE_ATTR_RW(post_reset_wdog); static
> DEVICE_ATTR_RW(reset_action); static
> DEVICE_ATTR_RW(second_reset_action);
> 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 struct attribute *mlxbf_bootctl_attrs[] = {
> &dev_attr_post_reset_wdog.attr,
> @@ -280,6 +407,7 @@ static struct attribute *mlxbf_bootctl_attrs[] = {
> &dev_attr_lifecycle_state.attr,
> &dev_attr_secure_boot_fuse_state.attr,
> &dev_attr_fw_reset.attr,
> + &dev_attr_rsh_log.attr,
> NULL
> };
>
> @@ -345,6 +473,7 @@ static bool mlxbf_bootctl_guid_match(const guid_t *guid,
> static int mlxbf_bootctl_probe(struct platform_device *pdev) {
> struct arm_smccc_res res = { 0 };
> + void __iomem *reg;
> guid_t guid;
> int ret;
>
> @@ -358,6 +487,18 @@ static int mlxbf_bootctl_probe(struct platform_device
> *pdev)
> if (IS_ERR(mlxbf_rsh_boot_cnt))
> return PTR_ERR(mlxbf_rsh_boot_cnt);
>
> + /* Get the resource of the bootfifo counter register. */
Wrong comment, seems like cut-and-paste error
> + mlxbf_rsh_semaphore = devm_platform_ioremap_resource(pdev, 2);
> + if (IS_ERR(mlxbf_rsh_semaphore))
> + return PTR_ERR(mlxbf_rsh_semaphore);
> +
> + /* Get the resource of the bootfifo counter register. */
Wrong comment, seems like cut-and-paste error
> + reg = devm_platform_ioremap_resource(pdev, 3);
> + if (IS_ERR(reg))
> + return PTR_ERR(reg);
> + mlxbf_rsh_scratch_buf_ctl = reg + MLXBF_RSH_SCRATCH_BUF_CTL_OFF;
> + mlxbf_rsh_scratch_buf_data = reg +
> MLXBF_RSH_SCRATCH_BUF_DATA_OFF;
> +
> /* 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);
> --
> 2.30.1
