DMA4 channel fails to continue with descriptor load when pause bit is cleared through config port access while in mstandby. Work around: Software should configure DMA in no standby mode or force standby before clearing the pause bit(CDPi[7]) using mstandby mode control API's. Applicable for all versions of OMAP3630 silicons. Signed-off-by: G, Manjunath Kondaiah <manjugk@xxxxxx> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> Cc: Tony Lindgren <tony@xxxxxxxxxxx> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx> Cc: Benoit Cousson <b-cousson@xxxxxx> --- arch/arm/mach-omap2/dma.c | 18 ++++++++++++++++++ arch/arm/plat-omap/include/plat/dma.h | 1 + 2 files changed, 19 insertions(+), 0 deletions(-) diff --git a/arch/arm/mach-omap2/dma.c b/arch/arm/mach-omap2/dma.c index 290b40c..86c8d20 100644 --- a/arch/arm/mach-omap2/dma.c +++ b/arch/arm/mach-omap2/dma.c @@ -689,6 +689,17 @@ static u32 configure_dma_errata(void) if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP)) SET_DMA_ERRATA(DMA_ROMCODE_BUG); + /* + * Erratum i557 - DMA4 channel fails to continue with descriptor load + * when pause bit is cleared through config port access while in + * standby. + * Work around: Software should configure DMA in no standby mode or + * Force standby before clearing the pause bit(CDPi[7]). + * Applicable for all versions of OMAP3630 silicons. + */ + if (cpu_is_omap3630()) + SET_DMA_ERRATA(DMA_ERRATA_i557); + return errata; } @@ -1431,12 +1442,19 @@ int omap_resume_dma_sglist_transfers(int lch, int pauseafter) */ wmb(); + if (IS_DMA_ERRATA(DMA_ERRATA_i557)) + omap_device_require_no_mstandby(pd); + /* Clear pause bit in CDP */ l = dma_read(CDP, lch); l &= ~(DMA_LIST_CDP_PAUSEMODE); dma_write(l, CDP, lch); omap_start_dma(lch); + + if (IS_DMA_ERRATA(DMA_ERRATA_i88)) + omap_device_release_no_mstandby(pd); + return 0; } EXPORT_SYMBOL(omap_resume_dma_sglist_transfers); diff --git a/arch/arm/plat-omap/include/plat/dma.h b/arch/arm/plat-omap/include/plat/dma.h index fd378f6..e18603d 100644 --- a/arch/arm/plat-omap/include/plat/dma.h +++ b/arch/arm/plat-omap/include/plat/dma.h @@ -285,6 +285,7 @@ #define DMA_ERRATA_i88 BIT(0x4) #define DMA_ERRATA_3_3 BIT(0x5) #define DMA_ROMCODE_BUG BIT(0x6) +#define DMA_ERRATA_i557 BIT(0x7) /* Attributes for OMAP DMA Contrller */ #define DMA_LINKED_LCH BIT(0x0) -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
