Re: [PATCH V2 6/8] spi: spi-geni-qcom: Add interconnect support

[Akash Asthana <akashast@xxxxxxxxxxxxxx>]

Hi Matthias,

On 3/14/2020 6:11 AM, Matthias Kaehlcke wrote:
> Hi Akash,
>
> On Fri, Mar 13, 2020 at 06:42:12PM +0530, Akash Asthana wrote:
> > Get the interconnect paths for SPI based Serial Engine device
> > and vote according to the current bus speed of the driver.
> >
> > Signed-off-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
> > ---
> >   - As per Bjorn's comment, removed se == NULL check from geni_spi_icc_get
> >   - As per Bjorn's comment, removed code to set se->icc_path* to NULL in failure
> >   - As per Bjorn's comment, introduced and using devm_of_icc_get API for getting
> >     path handle
> >   - As per Matthias comment, added error handling for icc_set_bw call
> >
> >   drivers/spi/spi-geni-qcom.c | 74 ++++++++++++++++++++++++++++++++++++++++++++-
> >   1 file changed, 73 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> > index c397242..09c4709 100644
> > --- a/drivers/spi/spi-geni-qcom.c
> > +++ b/drivers/spi/spi-geni-qcom.c
> > @@ -118,6 +118,19 @@ static int get_spi_clk_cfg(unsigned int speed_hz,
> >   	return ret;
> >   }
> >   
> > +static int geni_spi_icc_get(struct geni_se *se)
> > +{
> > +	se->icc_path_geni_to_core = devm_of_icc_get(se->dev, "qup-core");
> > +	if (IS_ERR(se->icc_path_geni_to_core))
> > +		return PTR_ERR(se->icc_path_geni_to_core);
> > +
> > +	se->icc_path_cpu_to_geni = devm_of_icc_get(se->dev, "qup-config");
> > +	if (IS_ERR(se->icc_path_cpu_to_geni))
> > +		return PTR_ERR(se->icc_path_cpu_to_geni);
> > +
> > +	return 0;
> > +}
> As per my comments on (https://patchwork.kernel.org/patch/11436895/#23222713),
> the above function could be replaced by calling a 'geni_icc_get()' (or so, to
> be created) provided by the geni SE driver.
ok
> > +
> >   static void handle_fifo_timeout(struct spi_master *spi,
> >   				struct spi_message *msg)
> >   {
> > @@ -234,6 +247,20 @@ static int setup_fifo_params(struct spi_device *spi_slv,
> >   		return ret;
> >   	}
> >   
> > +	/*
> > +	 * Set BW quota for CPU as driver supports FIFO mode only.
> > +	 * Assume peak bw as twice of avg bw.
> > +	 */
> > +	se->avg_bw_cpu = Bps_to_icc(mas->cur_speed_hz);
> > +	se->peak_bw_cpu = Bps_to_icc(2 * mas->cur_speed_hz);
> > +	ret = icc_set_bw(se->icc_path_cpu_to_geni, se->avg_bw_cpu,
> > +			se->peak_bw_cpu);
> > +	if (ret) {
> > +		dev_err(mas->dev, "%s: ICC BW voting failed for cpu\n",
> > +			__func__);
> > +		return ret;
> > +	}
> > +
> >   	clk_sel = idx & CLK_SEL_MSK;
> >   	m_clk_cfg = (div << CLK_DIV_SHFT) | SER_CLK_EN;
> >   	spi_setup_word_len(mas, spi_slv->mode, spi_slv->bits_per_word);
> > @@ -578,6 +605,15 @@ static int spi_geni_probe(struct platform_device *pdev)
> >   	spin_lock_init(&mas->lock);
> >   	pm_runtime_enable(dev);
> >   
> > +	ret = geni_spi_icc_get(&mas->se);
> > +	if (ret)
> > +		goto spi_geni_probe_runtime_disable;
> > +	/* Set the bus quota to a reasonable value for register access */
> > +	mas->se.avg_bw_core = Bps_to_icc(CORE_2X_50_MHZ);
> > +	mas->se.peak_bw_core = Bps_to_icc(CORE_2X_100_MHZ);
> > +	mas->se.avg_bw_cpu = Bps_to_icc(1000);
> > +	mas->se.peak_bw_cpu = Bps_to_icc(1000);
> > +
> >   	ret = spi_geni_init(mas);
> >   	if (ret)
> >   		goto spi_geni_probe_runtime_disable;
> > @@ -616,14 +652,50 @@ static int __maybe_unused spi_geni_runtime_suspend(struct device *dev)
> >   {
> >   	struct spi_master *spi = dev_get_drvdata(dev);
> >   	struct spi_geni_master *mas = spi_master_get_devdata(spi);
> > +	int ret;
> > +
> > +	ret = geni_se_resources_off(&mas->se);
> > +	if (ret)
> > +		return ret;
> >   
> > -	return geni_se_resources_off(&mas->se);
> > +	ret = icc_set_bw(mas->se.icc_path_geni_to_core, 0, 0);
> > +	if (ret) {
> > +		dev_err_ratelimited(mas->dev, "%s: ICC BW remove failed for core\n",
> > +			__func__);
> > +		return ret;
> > +	}
> > +
> > +	ret = icc_set_bw(mas->se.icc_path_cpu_to_geni, 0, 0);
> > +	if (ret) {
> > +		dev_err_ratelimited(mas->dev, "%s: ICC BW remove failed for cpu\n",
> > +			__func__);
> > +		return ret;
> > +	}
> the ICC stuff above would become:
>
> 	ret = geni_icc_vote_off(&mas->se);
> 	if (ret)
> 		return ret;
>
> with the consolidated code in geni SE.
ok
> > +
> > +	return 0;
> >   }
> >   
> >   static int __maybe_unused spi_geni_runtime_resume(struct device *dev)
> >   {
> >   	struct spi_master *spi = dev_get_drvdata(dev);
> >   	struct spi_geni_master *mas = spi_master_get_devdata(spi);
> > +	int ret;
> > +
> > +	ret = icc_set_bw(mas->se.icc_path_geni_to_core, mas->se.avg_bw_core,
> > +		mas->se.peak_bw_core);
> > +	if (ret) {
> > +		dev_err_ratelimited(mas->dev, "%s: ICC BW voting failed for core\n",
> > +			__func__);
> > +		return ret;
> > +	}
> > +
> > +	ret = icc_set_bw(mas->se.icc_path_cpu_to_geni, mas->se.avg_bw_cpu,
> > +		mas->se.peak_bw_cpu);
> > +	if (ret) {
> > +		dev_err_ratelimited(mas->dev, "%s: ICC BW voting failed for cpu\n",
> > +			__func__);
> > +		return ret;
> > +	}
> and this:
>
> 	ret = geni_icc_vote_on(&mas->se);
> 	if (ret)
> 		return ret;
ok
> >   	return geni_se_resources_on(&mas->se);
> possibly you could even do the ICC voting from geni_se_resources_on/off()
> it seems the two are always done together for UART, I2C and SPI.

I think we should expose geni_icc_vote_on/off API seperately and not 
merge to resources_on/off.

Because if we merge then it will appear that we are just doing 
geni_icc_get() from individual SE driver probe not using any of ICC apis.

It looks somewhat asymmetry.


Thanks for reviewing,

Regards,

Akash

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