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| author | Brian Norris <briannorris@chromium.org> | 2016-07-15 03:30:59 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2016-07-20 18:42:47 +0200 |
| commit | 5185a81c02d4118b11e6cb7b5fbf6f15ff7aff90 (patch) | |
| tree | 6eacba8fabd331367a9d99a9eb7b49418d36f74b /drivers/spi | |
| parent | Linux 4.7-rc1 (diff) | |
| download | linux-5185a81c02d4118b11e6cb7b5fbf6f15ff7aff90.tar.xz linux-5185a81c02d4118b11e6cb7b5fbf6f15ff7aff90.zip | |
spi: rockchip: limit transfers to (64K - 1) bytes
The Rockchip SPI controller's length register only supports 16-bits,
yielding a maximum length of 64KiB (the CTRLR1 register holds "length -
1"). Trying to transfer more than that (e.g., with a large SPI flash
read) will cause the driver to hang.
Now, it seems that while theoretically we should be able to program
CTRLR1 with 0xffff, and get a 64KiB transfer, but that also seems to
cause the core to choke, so stick with a maximum of 64K - 1 bytes --
i.e., 0xffff.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-rockchip.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c index cd89682065b9..cf69f4dfb8c7 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -142,6 +142,12 @@ /* sclk_out: spi master internal logic in rk3x can support 50Mhz */ #define MAX_SCLK_OUT 50000000 +/* + * SPI_CTRLR1 is 16-bits, so we should support lengths of 0xffff + 1. However, + * the controller seems to hang when given 0x10000, so stick with this for now. + */ +#define ROCKCHIP_SPI_MAX_TRANLEN 0xffff + enum rockchip_ssi_type { SSI_MOTO_SPI = 0, SSI_TI_SSP, @@ -573,6 +579,11 @@ static void rockchip_spi_config(struct rockchip_spi *rs) dev_dbg(rs->dev, "cr0 0x%x, div %d\n", cr0, div); } +static size_t rockchip_spi_max_transfer_size(struct spi_device *spi) +{ + return ROCKCHIP_SPI_MAX_TRANLEN; +} + static int rockchip_spi_transfer_one( struct spi_master *master, struct spi_device *spi, @@ -589,6 +600,11 @@ static int rockchip_spi_transfer_one( return -EINVAL; } + if (xfer->len > ROCKCHIP_SPI_MAX_TRANLEN) { + dev_err(rs->dev, "Transfer is too long (%d)\n", xfer->len); + return -EINVAL; + } + rs->speed = xfer->speed_hz; rs->bpw = xfer->bits_per_word; rs->n_bytes = rs->bpw >> 3; @@ -728,6 +744,7 @@ static int rockchip_spi_probe(struct platform_device *pdev) master->prepare_message = rockchip_spi_prepare_message; master->unprepare_message = rockchip_spi_unprepare_message; master->transfer_one = rockchip_spi_transfer_one; + master->max_transfer_size = rockchip_spi_max_transfer_size; master->handle_err = rockchip_spi_handle_err; rs->dma_tx.ch = dma_request_chan(rs->dev, "tx"); |