lkml.org 
[lkml]   [2018]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 3/6] spi: sun6i: restrict transfer length in PIO-mode
Date
There is no need to handle 3/4 empty/full interrupts as
the maximum supported transfer length in PIO mode is
128 bytes for sun6i- and 64 bytes for sun8i-family SoCs.

Signed-off-by: Sergey Suloev <ssuloev@orpaltech.com>

---
drivers/spi/spi-sun6i.c | 61 ++++++++++++++-----------------------------------
1 file changed, 17 insertions(+), 44 deletions(-)

diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
index 78acc1f..4db1f20 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;
}

static int sun6i_spi_prepare_message(struct spi_master *master,
@@ -250,13 +253,18 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
struct sun6i_spi *sspi = spi_master_get_devdata(master);
unsigned int mclk_rate, div, timeout;
unsigned int start, end, tx_time;
- unsigned int trig_level;
unsigned int tx_len = 0;
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 */
+ if (!tfr->len)
+ return 0;
+
+ /* Don't support transfer larger than the FIFO */
+ if (tfr->len > sspi->fifo_depth)
+ return -EMSGSIZE;

reinit_completion(&sspi->done);
sspi->tx_buf = tfr->tx_buf;
@@ -270,17 +278,6 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);

- /*
- * Setup FIFO interrupt trigger level
- * Here we choose 3/4 of the full fifo depth, as it's the hardcoded
- * value used in old generation of Allwinner SPI controller.
- * (See spi-sun4i.c)
- */
- 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));
-

reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
/*
@@ -342,12 +339,8 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
/* Fill the TX FIFO */
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);
+ /* Enable transfer complete interrupt */
+ sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TC);

/* Start the transfer */
reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
@@ -376,7 +369,9 @@ 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);

/* Transfer complete */
if (status & SUN6I_INT_CTL_TC) {
@@ -386,28 +381,6 @@ static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
return IRQ_HANDLED;
}

- /* Receive FIFO 3/4 full */
- if (status & SUN6I_INT_CTL_RF_RDY) {
- sun6i_spi_drain_fifo(sspi, SUN6I_FIFO_DEPTH);
- /* Only clear the interrupt _after_ draining the FIFO */
- sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
- return IRQ_HANDLED;
- }
-
- /* Transmit FIFO 3/4 empty */
- if (status & SUN6I_INT_CTL_TF_ERQ) {
- sun6i_spi_fill_fifo(sspi, SUN6I_FIFO_DEPTH);
-
- if (!sspi->len)
- /* nothing left to transmit */
- sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
-
- /* Only clear the interrupt _after_ re-seeding the FIFO */
- sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
-
- return IRQ_HANDLED;
- }
-
return IRQ_NONE;
}

--
2.16.2
\
 
 \ /
  Last update: 2018-03-30 14:52    [W:13.919 / U:3.988 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site