linux-kernel - Re: [PATCH v8 05/10] drivers: qcom: rpmh-rsc: write sleep/wake requests to TCS

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Date:   Wed, 9 May 2018 16:25:03 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Lina Iyer <ilina@...eaurora.org>
Cc:     andy.gross@...aro.org, david.brown@...aro.org,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        rnayak@...eaurora.org, bjorn.andersson@...aro.org,
        linux-kernel@...r.kernel.org, sboyd@...nel.org,
        evgreen@...omium.org, dianders@...omium.org, rplsssn@...eaurora.org
Subject: Re: [PATCH v8 05/10] drivers: qcom: rpmh-rsc: write sleep/wake
 requests to TCS

Hi Lina,

On Wed, May 09, 2018 at 11:01:54AM -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@...eaurora.org>
> Reviewed-by: Evan Green <evgreen@...omium.org>
> 
> ---
>
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index c0edf3850147..b5894b001ae1 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
>
> <snip>
>
> +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;
> +		if (i + len >= MAX_TCS_SLOTS)
> +			goto seq_err;

The command cache can have less than MAX_TCS_SLOTS slot:

static int rpmh_probe_tcs_config(struct platform_device *pdev,
				 struct rsc_drv *drv)
{
	...
	tcs->cmd_cache = devm_kcalloc(&pdev->dev,
				      tcs->num_tcs * ncpt, sizeof(u32),
				      GFP_KERNEL);
	...
}

So the condition needs to be:

if (i + len >= tcs->num_tcs * tcs->ncpt)

> +static int find_slots(struct tcs_group *tcs, const struct tcs_request *msg,
> +		      int *tcs_id, int *cmd_id)
> +{
> +	int slot, offset;
> +	int i = 0;
> +
> +	/* Find if we already have the msg in our TCS */
> +	slot = find_match(tcs, msg->cmds, msg->num_cmds);
> +	if (slot >= 0)
> +		goto copy_data;
> +
> +	/* Do over, until we can fit the full payload in a TCS */
> +	do {
> +		slot = bitmap_find_next_zero_area(tcs->slots, MAX_TCS_SLOTS,
> +						  i, msg->num_cmds, 0);
> +		if (slot == MAX_TCS_SLOTS)
> +			return -ENOMEM;

Like above, use 'tcs->num_tcs * tcs->ncpt' as maximum instead of
MAX_TCS_SLOTS.

> +static int tcs_ctrl_write(struct rsc_drv *drv, const struct tcs_request *msg)
> +{
> +	struct tcs_group *tcs;
> +	int tcs_id = 0, cmd_id = 0;
> +	unsigned long flags;
> +	int ret;
> +
> +	tcs = get_tcs_for_msg(drv, msg);
> +	if (IS_ERR(tcs))
> +		return PTR_ERR(tcs);
> +
> +	spin_lock_irqsave(&tcs->lock, flags);
> +	/* find the m-th TCS and the n-th position in the TCS to write to */

The comment still refers to the old names 'm' and 'n'.

Thanks

Matthias