diff options
| author | Alexandru Tachici <alexandru.tachici@analog.com> | 2021-07-17 00:02:45 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2021-07-20 13:34:05 +0100 |
| commit | c45c1e82bba130db4f19d9dbc1deefcf4ea994ed (patch) | |
| tree | dd15941be1c4c27dc22ae6b6721affdadb590c85 /drivers | |
| parent | 56912da7a68c8356df6a6740476237441b0b792a (diff) | |
spi: spi-bcm2835: Fix deadlock
The bcm2835_spi_transfer_one function can create a deadlock
if it is called while another thread already has the
CCF lock.
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Fixes: f8043872e796 ("spi: add driver for BCM2835")
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210716210245.13240-2-alexandru.tachici@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/spi/spi-bcm2835.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 5f8771fe1a31..775c0bf2f923 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -83,6 +83,7 @@ MODULE_PARM_DESC(polling_limit_us, * struct bcm2835_spi - BCM2835 SPI controller * @regs: base address of register map * @clk: core clock, divided to calculate serial clock + * @clk_hz: core clock cached speed * @irq: interrupt, signals TX FIFO empty or RX FIFO ¾ full * @tfr: SPI transfer currently processed * @ctlr: SPI controller reverse lookup @@ -116,6 +117,7 @@ MODULE_PARM_DESC(polling_limit_us, struct bcm2835_spi { void __iomem *regs; struct clk *clk; + unsigned long clk_hz; int irq; struct spi_transfer *tfr; struct spi_controller *ctlr; @@ -1045,19 +1047,18 @@ static int bcm2835_spi_transfer_one(struct spi_controller *ctlr, { struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr); struct bcm2835_spidev *slv = spi_get_ctldata(spi); - unsigned long spi_hz, clk_hz, cdiv; + unsigned long spi_hz, cdiv; unsigned long hz_per_byte, byte_limit; u32 cs = slv->prepare_cs; /* set clock */ spi_hz = tfr->speed_hz; - clk_hz = clk_get_rate(bs->clk); - if (spi_hz >= clk_hz / 2) { + if (spi_hz >= bs->clk_hz / 2) { cdiv = 2; /* clk_hz/2 is the fastest we can go */ } else if (spi_hz) { /* CDIV must be a multiple of two */ - cdiv = DIV_ROUND_UP(clk_hz, spi_hz); + cdiv = DIV_ROUND_UP(bs->clk_hz, spi_hz); cdiv += (cdiv % 2); if (cdiv >= 65536) @@ -1065,7 +1066,7 @@ static int bcm2835_spi_transfer_one(struct spi_controller *ctlr, } else { cdiv = 0; /* 0 is the slowest we can go */ } - tfr->effective_speed_hz = cdiv ? (clk_hz / cdiv) : (clk_hz / 65536); + tfr->effective_speed_hz = cdiv ? (bs->clk_hz / cdiv) : (bs->clk_hz / 65536); bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv); /* handle all the 3-wire mode */ @@ -1354,6 +1355,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev) return bs->irq ? bs->irq : -ENODEV; clk_prepare_enable(bs->clk); + bs->clk_hz = clk_get_rate(bs->clk); err = bcm2835_dma_init(ctlr, &pdev->dev, bs); if (err) |