Re: [PATCH 12/25] dmaengine: dw-edma: Fix DebugFS reg entry type

Manivannan Sadhasivam
2022-03-24T17:49:23Z

On Thu, Mar 24, 2022 at 04:48:23AM +0300, Serge Semin wrote:
> debugfs_entries structure declared in the dw-edma-v0-debugfs.c module
> contains the DebugFS node' register address. The address is declared as
> dma_addr_t type, but first it's assigned with virtual CPU IOMEM address
> and then it's cast back to the virtual address. Even though the castes
> sandwich will unlikely cause any problem since normally DMA address is at
> least of the same size as the CPU virtual address, it's at the very least
> redundant if not to say logically incorrect. Let's fix it by just stop
> casting the pointer back and worth and just preserve the address as a
> pointer to void with __iomem qualifier.
>
> Fixes: 305aebeff879 ("dmaengine: Add Synopsys eDMA IP version 0 debugfs support")
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Thanks,
Mani

> ---
> drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> index 3a899f7f4e8d..12845a2dc016 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
> @@ -14,7 +14,7 @@
> #include "dw-edma-core.h"
>
> #define REGS_ADDR(name) \
> - ((void __force *)&regs->name)
> + ((void __iomem *)&regs->name)
> #define REGISTER(name) \
> { #name, REGS_ADDR(name) }
>
> @@ -48,12 +48,13 @@ static struct {
>
> struct debugfs_entries {
> const char *name;
> - dma_addr_t *reg;
> + void __iomem *reg;
> };
>
> static int dw_edma_debugfs_u32_get(void *data, u64 *val)
> {
> - void __iomem *reg = (void __force __iomem *)data;
> + void __iomem *reg = data;
> +
> if (dw->chip->mf == EDMA_MF_EDMA_LEGACY &&
> reg >= (void __iomem *)&regs->type.legacy.ch) {
> void __iomem *ptr = &regs->type.legacy.ch;
> --
> 2.35.1
>