Re: [PATCH] mmc: dw_mmc: use resource_size_t to store physical address

From: Andy Shevchenko
Date: Thu Nov 12 2015 - 20:10:22 EST

On Thu, Nov 12, 2015 at 4:14 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> The dw_mmc driver stores the physical address of the MMIO registers
> in a pointer, which requires the use of type casts, and is actually
> broken if anyone ever has this device on a 32-bit SoC in registers
> above 4GB. Gcc warns about this possibility when the driver is built
> with ARM LPAE enabled:

> - host->phy_regs = (void *)(regs->start);
> + host->phy_regs = regs->start;

> /* Set external dma config: burst size, burst width */
> - cfg.dst_addr = (dma_addr_t)(host->phy_regs + fifo_offset);
> + cfg.dst_addr = host->phy_regs + fifo_offset;

dst_addr is dma_addr_t?

> /* Registers's physical base address */
> - void *phy_regs;
> + resource_size_t phy_regs;

If dst_addr is dma_addr_t wouldn't be a problem when
resource_size_t is defined as 64-bit address, and dma_addr_t as 32-bit?

Btw, for me casting to dma_addr_t looks sane.

With Best Regards,
Andy Shevchenko
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