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Subject: Re: [PATCHv3/RESEND 1/3] soc: qcom: rpmh-rsc: Remove tcs_is_free()
 API
To:     Stephen Boyd <swboyd@chromium.org>, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        Douglas Anderson <dianders@chromium.org>
References: <20200521060425.24285-1-swboyd@chromium.org>
 <20200521060425.24285-2-swboyd@chromium.org>
From:   Maulik Shah <mkshah@codeaurora.org>
Message-ID: <aa0d22f3-1885-4937-7410-c6c467008c7a@codeaurora.org>
Date:   Tue, 26 May 2020 12:37:06 +0530
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Hi,

Reviewed-by: Maulik Shah <mkshah@codeaurora.org>

Thanks,
Maulik

On 5/21/2020 11:34 AM, Stephen Boyd wrote:
> This API does very little. Let's replace all the callsites with the
> normal operations that would be done on top of the bitmap that
> tcs_in_use is. This simplifies and reduces the code size.
>
> Cc: Maulik Shah <mkshah@codeaurora.org>
> Cc: Douglas Anderson <dianders@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>   drivers/soc/qcom/rpmh-rsc.c | 59 +++++++++++++------------------------
>   1 file changed, 20 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index 076fd27f3081..60fc56987659 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
> @@ -184,22 +184,6 @@ static void write_tcs_reg_sync(const struct rsc_drv *drv, int reg, int tcs_id,
>   		       data, tcs_id, reg);
>   }
>   
> -/**
> - * tcs_is_free() - Return if a TCS is totally free.
> - * @drv:    The RSC controller.
> - * @tcs_id: The global ID of this TCS.
> - *
> - * Returns true if nobody has claimed this TCS (by setting tcs_in_use).
> - *
> - * Context: Must be called with the drv->lock held.
> - *
> - * Return: true if the given TCS is free.
> - */
> -static bool tcs_is_free(struct rsc_drv *drv, int tcs_id)
> -{
> -	return !test_bit(tcs_id, drv->tcs_in_use);
> -}
> -
>   /**
>    * tcs_invalidate() - Invalidate all TCSes of the given type (sleep or wake).
>    * @drv:  The RSC controller.
> @@ -512,7 +496,7 @@ static void __tcs_buffer_write(struct rsc_drv *drv, int tcs_id, int cmd_id,
>    *
>    * Return: 0 if nothing in flight or -EBUSY if we should try again later.
>    *         The caller must re-enable interrupts between tries since that's
> - *         the only way tcs_is_free() will ever return true and the only way
> + *         the only way tcs_in_use will ever be updated and the only way
>    *         RSC_DRV_CMD_ENABLE will ever be cleared.
>    */
>   static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
> @@ -520,17 +504,14 @@ static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
>   {
>   	unsigned long curr_enabled;
>   	u32 addr;
> -	int i, j, k;
> -	int tcs_id = tcs->offset;
> +	int j, k;
> +	int i = tcs->offset;
>   
> -	for (i = 0; i < tcs->num_tcs; i++, tcs_id++) {
> -		if (tcs_is_free(drv, tcs_id))
> -			continue;
> -
> -		curr_enabled = read_tcs_reg(drv, RSC_DRV_CMD_ENABLE, tcs_id);
> +	for_each_set_bit_from(i, drv->tcs_in_use, tcs->offset + tcs->num_tcs) {
> +		curr_enabled = read_tcs_reg(drv, RSC_DRV_CMD_ENABLE, i);
>   
>   		for_each_set_bit(j, &curr_enabled, MAX_CMDS_PER_TCS) {
> -			addr = read_tcs_cmd(drv, RSC_DRV_CMD_ADDR, tcs_id, j);
> +			addr = read_tcs_cmd(drv, RSC_DRV_CMD_ADDR, i, j);
>   			for (k = 0; k < msg->num_cmds; k++) {
>   				if (addr == msg->cmds[k].addr)
>   					return -EBUSY;
> @@ -548,18 +529,19 @@ static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
>    *
>    * Must be called with the drv->lock held since that protects tcs_in_use.
>    *
> - * Return: The first tcs that's free.
> + * Return: The first tcs that's free or -EBUSY if all in use.
>    */
>   static int find_free_tcs(struct tcs_group *tcs)
>   {
> -	int i;
> +	const struct rsc_drv *drv = tcs->drv;
> +	unsigned long i;
> +	unsigned long max = tcs->offset + tcs->num_tcs;
>   
> -	for (i = 0; i < tcs->num_tcs; i++) {
> -		if (tcs_is_free(tcs->drv, tcs->offset + i))
> -			return tcs->offset + i;
> -	}
> +	i = find_next_zero_bit(drv->tcs_in_use, max, tcs->offset);
> +	if (i >= max)
> +		return -EBUSY;
>   
> -	return -EBUSY;
> +	return i;
>   }
>   
>   /**
> @@ -757,8 +739,9 @@ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv, const struct tcs_request *msg)
>    */
>   static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv)
>   {
> -	int m;
> -	struct tcs_group *tcs = &drv->tcs[ACTIVE_TCS];
> +	unsigned long set;
> +	const struct tcs_group *tcs = &drv->tcs[ACTIVE_TCS];
> +	unsigned long max;
>   
>   	/*
>   	 * If we made an active request on a RSC that does not have a
> @@ -769,12 +752,10 @@ static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv)
>   	if (!tcs->num_tcs)
>   		tcs = &drv->tcs[WAKE_TCS];
>   
> -	for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) {
> -		if (!tcs_is_free(drv, m))
> -			return true;
> -	}
> +	max = tcs->offset + tcs->num_tcs;
> +	set = find_next_bit(drv->tcs_in_use, max, tcs->offset);
>   
> -	return false;
> +	return set < max;
>   }
>   
>   /**

-- 
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