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dmaengine: qcom: gpi: order event ring pointer reads #45

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dmaengine: qcom: gpi: order event ring pointer reads #45

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12 changes: 9 additions & 3 deletions drivers/dma/qcom/gpi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -662,8 +662,14 @@ static inline u32 gpi_read_reg(struct gpii *gpii, void __iomem *addr)

static phys_addr_t gpi_read_ev_rp(struct gpii *gpii)
{
u32 lsb = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg);
u32 msb;
u32 lsb, msb;

/*
* The event read pointer publishes entries written by the device into
* coherent memory. Use ordered MMIO reads so those writes are visible
* before the caller consumes an event from the ring.
*/
lsb = readl(gpii->ev_ring_rp_lsb_reg);

/*
* Denali publishes and may inspect the event ring before either QSPI
Expand All @@ -674,7 +680,7 @@ static phys_addr_t gpi_read_ev_rp(struct gpii *gpii)
if (!gpii_has_denali_qspi(gpii))
return lsb;

msb = gpi_read_reg(gpii, gpii->ev_ring_rp_lsb_reg + 4);
msb = readl(gpii->ev_ring_rp_lsb_reg + 4);

return ((phys_addr_t)msb << 32) | lsb;
}
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