[PATCH] ARM: tegra: only run PL310 init on systems with one

[Luís Henriques]

On Wed, Feb 26, 2014 at 11:02:26AM -0700, Stephen Warren wrote:
> From: Stephen Warren <swarren at nvidia.com>
> 
> (This is commit 8859685785bfafadf9bc922dd3a2278e59886947 upstream)
> 
> Fix tegra_init_cache() to check whether the system has a PL310 cache
> before touching the PL310 registers. This prevents access to non-existent
> registers on Tegra114 and later.
> 
> (When applying this to 3.10, there will be a trivial conflict, just due to
> context differences, at the added include of (linux/of.h>)
> 
> (I applied and tested this backport on each of v3.10.*, v3.11.*, v3.12.*)

Thanks a lot for backporting and testing this patch.  I will queue it for
the 3.11 kernel.

Cheers,
--
Luís

> Cc: <stable at vger.kernel.org> # v3.10..v3.12 inclusive
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
>  arch/arm/mach-tegra/common.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
> index 94a119a35af8..3c405f43ca39 100644
> --- a/arch/arm/mach-tegra/common.c
> +++ b/arch/arm/mach-tegra/common.c
> @@ -22,6 +22,7 @@
>  #include <linux/io.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> +#include <linux/of.h>
>  #include <linux/reboot.h>
>  #include <linux/irqchip.h>
>  #include <linux/clk-provider.h>
> @@ -82,10 +83,20 @@ void tegra_assert_system_reset(enum reboot_mode mode, const char *cmd)
>  static void __init tegra_init_cache(void)
>  {
>  #ifdef CONFIG_CACHE_L2X0
> +	static const struct of_device_id pl310_ids[] __initconst = {
> +		{ .compatible = "arm,pl310-cache",  },
> +		{}
> +	};
> +
> +	struct device_node *np;
>  	int ret;
>  	void __iomem *p = IO_ADDRESS(TEGRA_ARM_PERIF_BASE) + 0x3000;
>  	u32 aux_ctrl, cache_type;
>  
> +	np = of_find_matching_node(NULL, pl310_ids);
> +	if (!np)
> +		return;
> +
>  	cache_type = readl(p + L2X0_CACHE_TYPE);
>  	aux_ctrl = (cache_type & 0x700) << (17-8);
>  	aux_ctrl |= 0x7C400001;
> -- 
> 1.8.1.5
> 
> --
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