Re: [PATCH] dmaengine: dw-edma: Fix linked list physical address calculation on non-64 bits architectures

Vinod Koul
2020-08-27T05:10:54Z

On 26-08-20, 12:31, Gustavo Pimentel wrote:
> On Tue, Aug 25, 2020 at 12:9:37, Vinod Koul <vkoul@kernel.org> wrote:
>
> > On 13-08-20, 16:13, Gustavo Pimentel wrote:
> > > Fix linked list physical address calculation on non-64 bits architectures.
> > >
> > > The paddr variable is phys_addr_t type, which can assume a different
> > > type (u64 or u32) depending on the conditional compilation flag
> > > CONFIG_PHYS_ADDR_T_64BIT.
> > >
> > > Since this variable is used in with upper_32 bits() macro to get the
> > > value from 32 to 63 bits, on a non-64 bits architecture this variable
> > > will assume a u32 type, it can cause a compilation warning.
> > >
> > > This issue was reported by a Coverity analysis.
> > >
> > > Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
> > >
> > > Cc: Joao Pinto <jpinto@synopsys.com>
> > > Cc: stable@vger.kernel.org
> > > Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> > > ---
> > > drivers/dma/dw-edma/dw-edma-v0-core.c | 23 +++++++++++++++++------
> > > 1 file changed, 17 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> > > index 692de47..cfabbf5 100644
> > > --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> > > +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> > > @@ -229,8 +229,13 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
> > > /* Channel control */
> > > SET_LL(&llp->control, control);
> > > /* Linked list - low, high */
> > > - SET_LL(&llp->llp_low, lower_32_bits(chunk->ll_region.paddr));
> > > - SET_LL(&llp->llp_high, upper_32_bits(chunk->ll_region.paddr));
> > > + #ifdef CONFIG_PHYS_ADDR_T_64BIT
> > > + SET_LL(&llp->llp_low, lower_32_bits(chunk->ll_region.paddr));
> > > + SET_LL(&llp->llp_high, upper_32_bits(chunk->ll_region.paddr));
> > > + #else /* CONFIG_PHYS_ADDR_T_64BIT */
> > > + SET_LL(&llp->llp_low, chunk->ll_region.paddr);
> > > + SET_LL(&llp->llp_high, 0x0);
> >
> > Shouldn't upper_32_bits(chunk->ll_region.paddr) return zero for non
> > 64bit archs?
>
> At the time when I made this patch, I got a compiler warning about the
> u32 vs u64 type mixing (phys_addr_t) and the macro usage upper_32 bits()
> on non-64 bits architectures. That's why I made this patch, but now I
> don't see this warning anymore.
>
> Vinod, please disregard this patch.

Ok dropped

--
~Vinod