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

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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: Mark Brown <broonie@kernel.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200701174506.3.I2b3d7aeb1ea622335482cce60c58d2f8381e61dd@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
This commit is contained in:
Douglas Anderson 2020-07-01 17:45:09 -07:00 committed by Bjorn Andersson
parent 5f219524ec
commit da48dc8c70
1 changed files with 24 additions and 30 deletions
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54
drivers/spi/spi-geni-qcom.c
View file

@ -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);
}
@ -242,38 +240,34 @@ 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;
if (spi_slv->mode & SPI_LOOP)
loopback_cfg |= LOOPBACK_ENABLE;
if (spi_slv->mode & SPI_CPOL)
cpol = CPOL;
if (spi_slv->mode & SPI_CPOL)
cpol |= CPOL;
if (spi_slv->mode & SPI_CPHA)
cpha = CPHA;
if (spi_slv->mode & SPI_CPHA)
cpha |= CPHA;
if (spi_slv->mode & SPI_CS_HIGH)
demux_output_inv = BIT(spi_slv->chip_select);
if (spi_slv->mode & SPI_CS_HIGH)
demux_output_inv = BIT(spi_slv->chip_select);
demux_sel = spi_slv->chip_select;
mas->cur_bits_per_word = spi_slv->bits_per_word;
demux_sel = spi_slv->chip_select;
mas->cur_bits_per_word = spi_slv->bits_per_word;
spi_setup_word_len(mas, spi_slv->mode, spi_slv->bits_per_word);
writel(loopback_cfg, se->base + SE_SPI_LOOPBACK);
writel(demux_sel, se->base + SE_SPI_DEMUX_SEL);
writel(cpha, se->base + SE_SPI_CPHA);
writel(cpol, se->base + SE_SPI_CPOL);
writel(demux_output_inv, se->base + SE_SPI_DEMUX_OUTPUT_INV);
spi_setup_word_len(mas, spi_slv->mode, spi_slv->bits_per_word);
writel(loopback_cfg, se->base + SE_SPI_LOOPBACK);
writel(demux_sel, se->base + SE_SPI_DEMUX_SEL);
writel(cpha, se->base + SE_SPI_CPHA);
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;
}