From: Alexandru Tachici alexandru.tachici@analog.com
[ Upstream commit c45c1e82bba130db4f19d9dbc1deefcf4ea994ed ]
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.co... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi-bcm2835.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 29ee555a42f9..33c32e931767 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -84,6 +84,7 @@ 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 @@ -124,6 +125,7 @@ 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; @@ -1082,19 +1084,18 @@ static int bcm2835_spi_transfer_one(struct spi_controller *ctlr, struct spi_transfer *tfr) { struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr); - unsigned long spi_hz, clk_hz, cdiv; + unsigned long spi_hz, cdiv; unsigned long hz_per_byte, byte_limit; u32 cs = bs->prepare_cs[spi->chip_select];
/* 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) @@ -1102,7 +1103,7 @@ 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 */ @@ -1318,6 +1319,7 @@ 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)