Messages in this thread | | | Subject | Re: [PATCH] net: macb: Clean 64b dma addresses if they are not detected | From | Michal Simek <> | Date | Thu, 20 Sep 2018 08:23:58 +0200 |
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On 19.9.2018 20:08, Edgar E. Iglesias wrote: > On Wed, Sep 19, 2018 at 06:08:18PM +0200, Michal Simek wrote: >> Clear ADDR64 dma bit in DMACFG register in case that HW_DMA_CAP_64B >> is not detected on 64bit system. >> The issue was observed when bootloader(u-boot) does not check macb >> feature at DCFG6 register (DAW64_OFFSET) and enabling 64bit dma support >> by default. Then macb driver is reading DMACFG register back and only >> adding 64bit dma configuration but not cleaning it out. >> >> This is also align with other features which are also cleared if they are not >> present. > > Hi Michal, > >> >> Signed-off-by: Michal Simek <michal.simek@xilinx.com> >> --- >> >> drivers/net/ethernet/cadence/macb_main.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c >> index 16e4ef7d7185..79707dff3f13 100644 >> --- a/drivers/net/ethernet/cadence/macb_main.c >> +++ b/drivers/net/ethernet/cadence/macb_main.c >> @@ -2163,6 +2163,8 @@ static void macb_configure_dma(struct macb *bp) >> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT >> if (bp->hw_dma_cap & HW_DMA_CAP_64B) >> dmacfg |= GEM_BIT(ADDR64); >> + else >> + dmacfg &= ~GEM_BIT(ADDR64); >> #endif > > I think you might want to do this clearing outside of the #ifdef. > If CONFIG_ARCH_DMA_ADDR_T_64BIT is not defined, we'd want to make > sure the ADDR64 is cleared. E.g something like: > > dmacfg &= ~GEM_BIT(ADDR64); > #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT > if (bp->hw_dma_cap & HW_DMA_CAP_64B) > dmacfg |= GEM_BIT(ADDR64); > #endif > > > Same thing for the USE_HWSTAMP/PTP flags below.
Origin patch, which introduce this read with mask, macfg = gem_readl(bp, DMACFG) & ~GEM_BF(RXBS, -1L); was done in 2011 and from that time this function was extended a little bit. I am even not quite sure if make sense to read this reg and apply setting on the top of it.
Nicolas: Isn't it better simply compose that reg from scratch?
Thanks, Michal
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