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SubjectRe: [PATCH v7 05/10] drivers: qcom: rpmh-rsc: write sleep/wake requests to TCS
Hi Lina,

On Wed, May 02, 2018 at 01:37:44PM -0600, Lina Iyer wrote:
> Sleep and wake requests are sent when the application processor
> subsystem of the SoC is entering deep sleep states like in suspend.
> These requests help lower the system power requirements when the
> resources are not in use.
>
> Sleep and wake requests are written to the TCS slots but are not
> triggered at the time of writing. The TCS are triggered by the firmware
> after the last of the CPUs has executed its WFI. Since these requests
> may come in different batches of requests, it is the job of this
> controller driver to find and arrange the requests into the available
> TCSes.
>
> Signed-off-by: Lina Iyer <ilina@codeaurora.org>
> Reviewed-by: Evan Green <evgreen@chromium.org>
>
> ---
>
> Changes in v7:
> - Bug fix in find_match()
> ---
> drivers/soc/qcom/rpmh-internal.h | 8 +++
> drivers/soc/qcom/rpmh-rsc.c | 118 +++++++++++++++++++++++++++++++
> 2 files changed, 126 insertions(+)
>
> diff --git a/drivers/soc/qcom/rpmh-internal.h b/drivers/soc/qcom/rpmh-internal.h
> index d9a21726e568..6e19fe458c31 100644
> --- a/drivers/soc/qcom/rpmh-internal.h
> +++ b/drivers/soc/qcom/rpmh-internal.h
> @@ -14,6 +14,7 @@
> #define MAX_CMDS_PER_TCS 16
> #define MAX_TCS_PER_TYPE 3
> #define MAX_TCS_NR (MAX_TCS_PER_TYPE * TCS_TYPE_NR)
> +#define MAX_TCS_SLOTS (MAX_CMDS_PER_TCS * MAX_TCS_PER_TYPE)
> #define RPMH_MAX_CTRLR 2
>
> struct rsc_drv;
> @@ -30,6 +31,8 @@ struct rsc_drv;
> * @ncpt: number of commands in each TCS
> * @lock: lock for synchronizing this TCS writes
> * @req: requests that are sent from the TCS
> + * @cmd_cache: flattened cache of cmds in sleep/wake TCS
> + * @slots: indicates which of @cmd_addr are occupied
> */
> struct tcs_group {
> struct rsc_drv *drv;
> @@ -40,6 +43,8 @@ struct tcs_group {
> int ncpt;
> spinlock_t lock;
> const struct tcs_request *req[MAX_TCS_PER_TYPE];
> + u32 *cmd_cache;
> + DECLARE_BITMAP(slots, MAX_TCS_SLOTS);
> };
>
> /**
> @@ -69,6 +74,9 @@ struct rsc_drv {
> extern struct list_head rsc_drv_list;
>
> int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg);
> +int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv,
> + const struct tcs_request *msg);
> +int rpmh_rsc_invalidate(struct rsc_drv *drv);
>
> void rpmh_tx_done(const struct tcs_request *msg, int r);
>
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index 33270b1d5991..4e2144a14c31 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
> @@ -113,6 +113,12 @@ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
> case RPMH_ACTIVE_ONLY_STATE:
> type = ACTIVE_TCS;
> break;
> + case RPMH_WAKE_ONLY_STATE:
> + type = WAKE_TCS;
> + break;
> + case RPMH_SLEEP_STATE:
> + type = SLEEP_TCS;
> + break;
> default:
> return ERR_PTR(-EINVAL);
> }
> @@ -353,6 +359,105 @@ int rpmh_rsc_send_data(struct rsc_drv *drv, const struct tcs_request *msg)
> }
> EXPORT_SYMBOL(rpmh_rsc_send_data);
>
> +static int find_match(const struct tcs_group *tcs, const struct tcs_cmd *cmd,
> + int len)
> +{
> + int i, j;
> +
> + /* Check for already cached commands */
> + for_each_set_bit(i, tcs->slots, MAX_TCS_SLOTS) {
> + if (tcs->cmd_cache[i] != cmd[0].addr)
> + continue;
> + for (j = 0; j < len; j++) {
> + if (tcs->cmd_cache[i + j] != cmd[j].addr) {

As mentioned in the review of v6, the code could read memory beyond
tcs->cmd_cache if 'i + len > ARRAY_SIZE(tcs->cmd_cache)'

> + WARN(1, "Message does not match previous sequence.\n");
> + return -EINVAL;
> + }
> + }
> + return i;
> + }
> +
> + return -ENODATA;
> +}
> +
> +static int find_slots(struct tcs_group *tcs, const struct tcs_request *msg,
> + int *tcs_id, int *cmd_id)

The change from m/n => tcs_id/cmd_id in v7 greatly improves
readability, thanks!

Matthias

PS: Please remember to include reviewers of earlier revisions to cc:

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