lkml.org 
[lkml]   [2018]   [Apr]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 3/6] spi: sun6i: restrict transfer length in PIO-mode
On Tue, Apr 03, 2018 at 06:44:46PM +0300, Sergey Suloev wrote:
> There is no need to handle 3/4 empty interrupt as the maximum
> supported transfer length in PIO mode is equal to FIFO depth,
> i.e. 128 bytes for sun6i and 64 bytes for sun8i SoCs.
>
> Changes in v3:
> 1) Restored processing of 3/4 FIFO full interrupt.
>
> Signed-off-by: Sergey Suloev <ssuloev@orpaltech.com>
> ---
> drivers/spi/spi-sun6i.c | 41 +++++++++++++++++------------------------
> 1 file changed, 17 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
> index 78acc1f..c09ad10 100644
> --- a/drivers/spi/spi-sun6i.c
> +++ b/drivers/spi/spi-sun6i.c
> @@ -207,7 +207,10 @@ static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
>
> static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
> {
> - return SUN6I_MAX_XFER_SIZE - 1;
> + struct spi_master *master = spi->master;
> + struct sun6i_spi *sspi = spi_master_get_devdata(master);
> +
> + return sspi->fifo_depth;

Doesn't that effectively revert 3288d5cb40c0 ?

Why do you need to do so?

> }
>
> static int sun6i_spi_prepare_message(struct spi_master *master,
> @@ -255,8 +258,14 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
> int ret = 0;
> u32 reg;
>
> - if (tfr->len > SUN6I_MAX_XFER_SIZE)
> - return -EINVAL;
> + /* A zero length transfer never finishes if programmed
> + in the hardware */

Improper comment style here. Please make sure to run checkpatch before
sending your patches.

> + if (!tfr->len)
> + return 0;

Can that case even happen?

> + /* Don't support transfer larger than the FIFO */
> + if (tfr->len > sspi->fifo_depth)
> + return -EMSGSIZE;

You're changing the return type, why?

> reinit_completion(&sspi->done);
> sspi->tx_buf = tfr->tx_buf;
> @@ -278,8 +287,7 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
> */
> trig_level = sspi->fifo_depth / 4 * 3;
> sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
> - (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
> - (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS));
> + (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS));
>
>
> reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
> @@ -343,11 +351,8 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
> sun6i_spi_fill_fifo(sspi, sspi->fifo_depth);
>
> /* Enable the interrupts */
> - sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, SUN6I_INT_CTL_TC);
> sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TC |
> SUN6I_INT_CTL_RF_RDY);
> - if (tx_len > sspi->fifo_depth)
> - sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);

This would also need to be explained in your commit log.

>
> /* Start the transfer */
> reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
> @@ -376,7 +381,9 @@ out:
> static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
> {
> struct sun6i_spi *sspi = dev_id;
> - u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
> + u32 status;
> +
> + status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);

Why is this change needed?

Maxime

--
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-04-04 08:51    [W:0.137 / U:17.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site