| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 136/163] spi: rockchip: modify DMA max burst to 1 | Date | Mon, 2 May 2016 17:12:44 -0700 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Addy Ke <addy.ke@rock-chips.com>
commit 80abf8880cc6e1594c11b7c417f22dde60e25312 upstream.
Generic dma controller on Rockchips' platform cannot support DMAFLUSHP instruction which make dma to flush the req of non-aligned or non-multiple of what we need. That will cause an unrecoverable dma bus error. The saftest way is to set dma max burst to 1.
Signed-off-by: Addy ke <addy.ke@rock-chips.com> Fixes: 64e36824b32b06 ("spi/rockchip: add driver for Rockchip...") Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com> cc: Heiko Stuebner <heiko@sntech.de> cc: Olof Johansson <olof@lixom.net> cc: Doug Anderson <dianders@chromium.org> cc: Sonny Rao <sonnyrao@chromium.org> Acked-by: Mark Brown <broonie@kernel.org> Signed-off-by: Caesar Wang <wxt@rock-chips.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/spi/spi-rockchip.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
--- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -199,6 +199,7 @@ struct rockchip_spi { struct sg_table rx_sg; struct rockchip_spi_dma_data dma_rx; struct rockchip_spi_dma_data dma_tx; + struct dma_slave_caps dma_caps; }; static inline void spi_enable_chip(struct rockchip_spi *rs, int enable) @@ -454,7 +455,10 @@ static void rockchip_spi_prepare_dma(str rxconf.direction = rs->dma_rx.direction; rxconf.src_addr = rs->dma_rx.addr; rxconf.src_addr_width = rs->n_bytes; - rxconf.src_maxburst = rs->n_bytes; + if (rs->dma_caps.max_burst > 4) + rxconf.src_maxburst = 4; + else + rxconf.src_maxburst = 1; dmaengine_slave_config(rs->dma_rx.ch, &rxconf); rxdesc = dmaengine_prep_slave_sg( @@ -471,7 +475,10 @@ static void rockchip_spi_prepare_dma(str txconf.direction = rs->dma_tx.direction; txconf.dst_addr = rs->dma_tx.addr; txconf.dst_addr_width = rs->n_bytes; - txconf.dst_maxburst = rs->n_bytes; + if (rs->dma_caps.max_burst > 4) + txconf.dst_maxburst = 4; + else + txconf.dst_maxburst = 1; dmaengine_slave_config(rs->dma_tx.ch, &txconf); txdesc = dmaengine_prep_slave_sg( @@ -735,6 +742,7 @@ static int rockchip_spi_probe(struct pla } if (rs->dma_tx.ch && rs->dma_rx.ch) { + dma_get_slave_caps(rs->dma_rx.ch, &(rs->dma_caps)); rs->dma_tx.addr = (dma_addr_t)(mem->start + ROCKCHIP_SPI_TXDR); rs->dma_rx.addr = (dma_addr_t)(mem->start + ROCKCHIP_SPI_RXDR); rs->dma_tx.direction = DMA_MEM_TO_DEV;
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