Re: [PATCH 2/5] firmware: arm_scmi: Make use SCMI v2.0 fastchannel for performance protocol

[Etienne Carriere <etienne.carriere@linaro.org>]

On Fri, 26 Jul 2019 at 16:00, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> SCMI v2.0 adds support for "FastChannel" which do not use a message
> header as they are specialized for a single message.
>
> Only PERFORMANCE_LIMITS_{SET,GET} and PERFORMANCE_LEVEL_{SET,GET}
> commands are supported over fastchannels. As they are optional, they
> need to be discovered by PERFORMANCE_DESCRIBE_FASTCHANNEL command.
> Further {LIMIT,LEVEL}_SET commands can have optional doorbell support.
>
> Add support for making use of these fastchannels.
>
> Cc: Ionela Voinescu <Ionela.Voinescu@arm.com>
> Cc: Chris Redpath <Chris.Redpath@arm.com>
> Cc: Quentin Perret <Quentin.Perret@arm.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
>  drivers/firmware/arm_scmi/perf.c | 104 +++++++++++++++++++++++++++++--
>  1 file changed, 100 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
> index 6cce3e82e81e..b9144efbd6fb 100644
> --- a/drivers/firmware/arm_scmi/perf.c
> +++ b/drivers/firmware/arm_scmi/perf.c
> @@ -8,6 +8,7 @@
>  #include <linux/bits.h>
>  #include <linux/of.h>
>  #include <linux/io.h>
> +#include <linux/io-64-nonatomic-hi-lo.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_opp.h>
>  #include <linux/sort.h>
> @@ -293,7 +294,42 @@ scmi_perf_describe_levels_get(const struct scmi_handle *handle, u32 domain,
>         return ret;
>  }
>
> -static int scmi_perf_limits_set(const struct scmi_handle *handle, u32 domain,
> +#define SCMI_PERF_FC_RING_DB(doorbell, w)              \

Suggest to reformat into a macro style:
    #define SCMI_PERF_FC_RING_DB(doorbell, w)              \
        do { \
                (...) \
        } while (0)

> +{                                                      \
> +       u##w val = 0;                                   \
> +       struct scmi_fc_db_info *db = doorbell;          \
> +                                                       \
> +       if ((db)->mask)                                 \

remove parentheses. I would say, could simply remove `if (db->mask)` here.

> +               val = ioread##w(db->addr) & db->mask;   \
> +       iowrite##w((u##w)db->set | val, db->addr);      \
> +}
> +
> +static void scmi_perf_fc_ring_db(struct scmi_fc_db_info *db)
> +{
> +       if (!db || !db->addr)
> +               return;
> +
> +       if (db->width == 1)
> +               SCMI_PERF_FC_RING_DB(db, 8)
> +       else if (db->width == 2)
> +               SCMI_PERF_FC_RING_DB(db, 16)
> +       else if (db->width == 4)
> +               SCMI_PERF_FC_RING_DB(db, 32)
> +       else /* db->width == 8 */
> +#ifdef CONFIG_64BIT
> +               SCMI_PERF_FC_RING_DB(db, 64)
> +#else
> +       {
> +               u64 val = 0;
> +
> +               if (db->mask)
> +                       val = ioread64_hi_lo(db->addr) & db->mask;
> +               iowrite64_hi_lo(db->set, db->addr);

Is `value` missing here?
Why not using SCMI_PERF_FC_RING_DB(db, 64) here?



> +       }
> +#endif
> +}
> +
> +static int scmi_perf_mb_limits_set(const struct scmi_handle *handle, u32 domain,
>                                    u32 max_perf, u32 min_perf)
>  {
>         int ret;
> @@ -316,7 +352,23 @@ static int scmi_perf_limits_set(const struct scmi_handle *handle, u32 domain,
>         return ret;
>  }
>
> -static int scmi_perf_limits_get(const struct scmi_handle *handle, u32 domain,
> +static int scmi_perf_limits_set(const struct scmi_handle *handle, u32 domain,
> +                               u32 max_perf, u32 min_perf)
> +{
> +       struct scmi_perf_info *pi = handle->perf_priv;
> +       struct perf_dom_info *dom = pi->dom_info + domain;
> +
> +       if (dom->fc_info && dom->fc_info->limit_set_addr) {
> +               iowrite32(max_perf, dom->fc_info->limit_set_addr);
> +               iowrite32(min_perf, dom->fc_info->limit_set_addr + 4);
> +               scmi_perf_fc_ring_db(dom->fc_info->limit_set_db);
> +               return 0;
> +       }
> +
> +       return scmi_perf_mb_limits_set(handle, domain, max_perf, min_perf);
> +}
> +
> +static int scmi_perf_mb_limits_get(const struct scmi_handle *handle, u32 domain,
>                                    u32 *max_perf, u32 *min_perf)
>  {
>         int ret;
> @@ -342,7 +394,22 @@ static int scmi_perf_limits_get(const struct scmi_handle *handle, u32 domain,
>         return ret;
>  }
>
> -static int scmi_perf_level_set(const struct scmi_handle *handle, u32 domain,
> +static int scmi_perf_limits_get(const struct scmi_handle *handle, u32 domain,
> +                               u32 *max_perf, u32 *min_perf)
> +{
> +       struct scmi_perf_info *pi = handle->perf_priv;
> +       struct perf_dom_info *dom = pi->dom_info + domain;
> +
> +       if (dom->fc_info && dom->fc_info->limit_get_addr) {
> +               *max_perf = ioread32(dom->fc_info->limit_get_addr);
> +               *min_perf = ioread32(dom->fc_info->limit_get_addr + 4);
> +               return 0;
> +       }
> +
> +       return scmi_perf_mb_limits_get(handle, domain, max_perf, min_perf);
> +}
> +
> +static int scmi_perf_mb_level_set(const struct scmi_handle *handle, u32 domain,
>                                   u32 level, bool poll)
>  {
>         int ret;
> @@ -365,7 +432,22 @@ static int scmi_perf_level_set(const struct scmi_handle *handle, u32 domain,
>         return ret;
>  }
>
> -static int scmi_perf_level_get(const struct scmi_handle *handle, u32 domain,
> +static int scmi_perf_level_set(const struct scmi_handle *handle, u32 domain,
> +                              u32 level, bool poll)
> +{
> +       struct scmi_perf_info *pi = handle->perf_priv;
> +       struct perf_dom_info *dom = pi->dom_info + domain;
> +
> +       if (dom->fc_info && dom->fc_info->level_set_addr) {
> +               iowrite32(level, dom->fc_info->level_set_addr);
> +               scmi_perf_fc_ring_db(dom->fc_info->level_set_db);
> +               return 0;
> +       }
> +
> +       return scmi_perf_mb_level_set(handle, domain, level, poll);
> +}
> +
> +static int scmi_perf_mb_level_get(const struct scmi_handle *handle, u32 domain,
>                                   u32 *level, bool poll)
>  {
>         int ret;
> @@ -387,6 +469,20 @@ static int scmi_perf_level_get(const struct scmi_handle *handle, u32 domain,
>         return ret;
>  }
>
> +static int scmi_perf_level_get(const struct scmi_handle *handle, u32 domain,
> +                              u32 *level, bool poll)
> +{
> +       struct scmi_perf_info *pi = handle->perf_priv;
> +       struct perf_dom_info *dom = pi->dom_info + domain;
> +
> +       if (dom->fc_info && dom->fc_info->level_get_addr) {
> +               *level = ioread32(dom->fc_info->level_get_addr);
> +               return 0;
> +       }
> +
> +       return scmi_perf_mb_level_get(handle, domain, level, poll);
> +}
> +
>  static bool scmi_perf_fc_size_is_valid(u32 msg, u32 size)
>  {
>         if ((msg == PERF_LEVEL_GET || msg == PERF_LEVEL_SET) && size == 4)
> --
> 2.17.1
>