Re: [PATCH v4 09/15] memory: tegra: Squash tegra20-mc into common tegra-mc driver

[Thierry Reding]

On Mon, Apr 09, 2018 at 10:28:31PM +0300, Dmitry Osipenko wrote:
[...]
> diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
[...]
> +#define MC_GART_ERROR_REQ		0x30
> +#define MC_DECERR_EMEM_OTHERS_STATUS	0x58
> +#define MC_SECURITY_VIOLATION_STATUS	0x74
[...]
> diff --git a/drivers/memory/tegra/mc.h b/drivers/memory/tegra/mc.h
[...]
> @@ -21,19 +21,30 @@
>  #define MC_INT_INVALID_SMMU_PAGE (1 << 10)
>  #define MC_INT_ARBITRATION_EMEM (1 << 9)
>  #define MC_INT_SECURITY_VIOLATION (1 << 8)
> +#define MC_INT_INVALID_GART_PAGE (1 << 7)
>  #define MC_INT_DECERR_EMEM (1 << 6)
>  
>  static inline u32 mc_readl(struct tegra_mc *mc, unsigned long offset)
>  {
> +	if (mc->regs2 && offset >= 0x24)
> +		return readl(mc->regs2 + offset - 0x3c);

I'm still not sure how this is supposed to work. If we pass in
MC_GART_ERROR_REQ as offset into mc_readl(), then the condition above
will be true (0x30 >= 0x24) but then the new offset will be computed
and we end up with:

	return readl(mc->regs2 + 0x30 - 0x3c);

which means we'll be adding a negative offset (or rather a very large
offset because it will wrap around).

Thierry

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