Messages in this thread | | | Date | Thu, 18 Aug 2022 10:22:03 +0100 | Subject | Re: [PATCH] regmap: spi: Reserve space for register address/padding | From | Lucas tanure <> |
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On 8/17/22 22:38, Cristian Ciocaltea wrote: > Currently the max_raw_read and max_raw_write limits in regmap_spi struct > do not take into account the additional size of the transmitted register > address and padding. This may result in exceeding the maximum permitted > SPI transfer size, which could cause undefined behaviour, e.g. data > corruption. > > Fix regmap_get_spi_bus() to properly adjust the above mentioned limits > by reserving space for the register address/padding as set in the regmap > configuration. > > Fixes: f231ff38b7b2 ("regmap: spi: Set regmap max raw r/w from max_transfer_size") > > Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com> > --- > drivers/base/regmap/regmap-spi.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/base/regmap/regmap-spi.c b/drivers/base/regmap/regmap-spi.c > index 719323bc6c7f..6fb94c06a447 100644 > --- a/drivers/base/regmap/regmap-spi.c > +++ b/drivers/base/regmap/regmap-spi.c > @@ -113,6 +113,7 @@ static const struct regmap_bus *regmap_get_spi_bus(struct spi_device *spi, > const struct regmap_config *config) > { > size_t max_size = spi_max_transfer_size(spi); > + size_t max_msg_size, reg_reserve_size; > struct regmap_bus *bus; > > if (max_size != SIZE_MAX) { > @@ -120,9 +121,15 @@ static const struct regmap_bus *regmap_get_spi_bus(struct spi_device *spi, > if (!bus) > return ERR_PTR(-ENOMEM); > > + max_msg_size = spi_max_message_size(spi); > + reg_reserve_size = config->reg_bits / 8 + config->pad_bits / 8; I think you can use BITS_PER_BYTE here instead of 8.
> + if (max_size + reg_reserve_size > max_msg_size) > + max_size -= reg_reserve_size; > + > bus->free_on_exit = true; > bus->max_raw_read = max_size; > bus->max_raw_write = max_size; > + > return bus; > } > > base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868 > -- > 2.37.2
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