Commit da48dc8c authored by Douglas Anderson's avatar Douglas Anderson Committed by Bjorn Andersson
Browse files

spi: spi-geni-qcom: Get rid of most overhead in prepare_message() 



There's a bunch of overhead in spi-geni-qcom's prepare_message.  Get
rid of it.  Before this change spi_geni_prepare_message() took around
14.5 us.  After this change, spi_geni_prepare_message() takes about
1.75 us (as measured by ftrace).

What's here:
* We're always in FIFO mode, so no need to call it for every transfer.
  This avoids a whole ton of readl/writel calls.
* We don't need to write a whole pile of config registers if the mode
  isn't changing.  Cache the last mode and only do the work if needed.
* For several registers we were trying to do read/modify/write, but
  there was no reason.  The registers only have one thing in them, so
  just write them.

Acked-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarAkash Asthana <akashast@codeaurora.org>
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200701174506.3.I2b3d7aeb1ea622335482cce60c58d2f8381e61dd@changeid


Signed-off-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
parent 5f219524

drivers/spi/spi-geni-qcom.c

+24 −30
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ struct spi_geni_master { 
	u32 tx_fifo_depth;

	u32 fifo_width_bits;

	u32 tx_wm;

	u32 last_mode;

	unsigned long cur_speed_hz;

	unsigned long cur_sclk_hz;

	unsigned int cur_bits_per_word;
@@ -181,8 +182,6 @@ static void spi_setup_word_len(struct spi_geni_master *mas, u16 mode, 
	struct geni_se *se = &mas->se;

	u32 word_len;



	word_len = readl(se->base + SE_SPI_WORD_LEN);



	/*

	 * If bits_per_word isn't a byte aligned value, set the packing to be

	 * 1 SPI word per FIFO word.
@@ -191,10 +190,9 @@ static void spi_setup_word_len(struct spi_geni_master *mas, u16 mode, 
		pack_words = mas->fifo_width_bits / bits_per_word;

	else

		pack_words = 1;

	word_len &= ~WORD_LEN_MSK;

	word_len |= ((bits_per_word - MIN_WORD_LEN) & WORD_LEN_MSK);

	geni_se_config_packing(&mas->se, bits_per_word, pack_words, msb_first,

								true, true);

	word_len = (bits_per_word - MIN_WORD_LEN) & WORD_LEN_MSK;

	writel(word_len, se->base + SE_SPI_WORD_LEN);

}
@@ -242,25 +240,18 @@ static int setup_fifo_params(struct spi_device *spi_slv, 
{

	struct spi_geni_master *mas = spi_master_get_devdata(spi);

	struct geni_se *se = &mas->se;

	u32 loopback_cfg, cpol, cpha, demux_output_inv;

	u32 loopback_cfg = 0, cpol = 0, cpha = 0, demux_output_inv = 0;

	u32 demux_sel;



	loopback_cfg = readl(se->base + SE_SPI_LOOPBACK);

	cpol = readl(se->base + SE_SPI_CPOL);

	cpha = readl(se->base + SE_SPI_CPHA);

	demux_output_inv = 0;

	loopback_cfg &= ~LOOPBACK_MSK;

	cpol &= ~CPOL;

	cpha &= ~CPHA;



	if (mas->last_mode != spi_slv->mode) {

		if (spi_slv->mode & SPI_LOOP)

		loopback_cfg |= LOOPBACK_ENABLE;

			loopback_cfg = LOOPBACK_ENABLE;



		if (spi_slv->mode & SPI_CPOL)

		cpol |= CPOL;

			cpol = CPOL;



		if (spi_slv->mode & SPI_CPHA)

		cpha |= CPHA;

			cpha = CPHA;



		if (spi_slv->mode & SPI_CS_HIGH)

			demux_output_inv = BIT(spi_slv->chip_select);
@@ -275,6 +266,9 @@ static int setup_fifo_params(struct spi_device *spi_slv, 
		writel(cpol, se->base + SE_SPI_CPOL);

		writel(demux_output_inv, se->base + SE_SPI_DEMUX_OUTPUT_INV);



		mas->last_mode = spi_slv->mode;

	}



	return geni_spi_set_clock_and_bw(mas, spi_slv->max_speed_hz);

}
@@ -283,9 +277,7 @@ static int spi_geni_prepare_message(struct spi_master *spi, 
{

	int ret;

	struct spi_geni_master *mas = spi_master_get_devdata(spi);

	struct geni_se *se = &mas->se;



	geni_se_select_mode(se, GENI_SE_FIFO);

	ret = setup_fifo_params(spi_msg->spi, spi);

	if (ret)

		dev_err(mas->dev, "Couldn't select mode %d\n", ret);
@@ -326,6 +318,8 @@ static int spi_geni_init(struct spi_geni_master *mas) 
	else

		mas->oversampling = 1;



	geni_se_select_mode(se, GENI_SE_FIFO);



	pm_runtime_put(mas->dev);

	return 0;

}

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