[PATCH v2] ARM: imx6: add OF fixup to delete nonexistent CPU cores

[PATCH v2] ARM: imx6: add OF fixup to delete nonexistent CPU cores

[Lucas Stach]

Make sure that the DT passed to Linux reflects the actual number of CPU
cores present in the system by reading the SCU configuration. As both
the Q and DL variants of the MX6 have versions with cores fused away,
but the DTs have the maximum number of cores specified, this just deletes
any nonexistent CPU core nodes.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
v2:
- make sure to only install the fixup on i.MX6
---
 arch/arm/mach-imx/imx6.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/arch/arm/mach-imx/imx6.c b/arch/arm/mach-imx/imx6.c
index c49de49209f3..0fdd785c6dc6 100644
--- a/arch/arm/mach-imx/imx6.c
+++ b/arch/arm/mach-imx/imx6.c
@@ -238,3 +238,42 @@ static int imx6_mmu_init(void)
 	return 0;
 }
 postmmu_initcall(imx6_mmu_init);
+
+#define SCU_CONFIG	0x04
+
+static int imx6_fixup_cpus(struct device_node *root, void *context)
+{
+	struct device_node *cpus_node, *np, *tmp;
+	unsigned long scu_phys_base;
+	unsigned int max_core_index;
+
+	cpus_node = of_find_node_by_name(root, "cpus");
+	if (!cpus_node)
+		return 0;
+
+	/* get actual number of available CPU cores from SCU */
+	asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (scu_phys_base));
+	max_core_index = (readl(IOMEM(scu_phys_base) + SCU_CONFIG) & 0x03);
+
+	for_each_child_of_node_safe(cpus_node, tmp, np) {
+		u32 cpu_index;
+
+		if (of_property_read_u32(np, "reg", &cpu_index))
+			continue;
+
+		if (cpu_index > max_core_index)
+			of_delete_node(np);
+	}
+
+	return 0;
+}
+
+static int imx6_fixup_cpus_register(void)
+{
+	if (!of_machine_is_compatible("fsl,imx6q") &&
+	    !of_machine_is_compatible("fsl,imx6dl"))
+		return 0;
+
+	return of_register_fixup(imx6_fixup_cpus, NULL);
+}
+device_initcall(imx6_fixup_cpus_register);
-- 
2.6.1


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

Re: [PATCH v2] ARM: imx6: add OF fixup to delete nonexistent CPU cores

[Sascha Hauer]

On Tue, Oct 27, 2015 at 04:09:29PM +0100, Lucas Stach wrote:
> Make sure that the DT passed to Linux reflects the actual number of CPU
> cores present in the system by reading the SCU configuration. As both
> the Q and DL variants of the MX6 have versions with cores fused away,
> but the DTs have the maximum number of cores specified, this just deletes
> any nonexistent CPU core nodes.
> 
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> ---
> v2:
> - make sure to only install the fixup on i.MX6

Applied, thanks

Sascha

> ---
>  arch/arm/mach-imx/imx6.c | 39 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/imx6.c b/arch/arm/mach-imx/imx6.c
> index c49de49209f3..0fdd785c6dc6 100644
> --- a/arch/arm/mach-imx/imx6.c
> +++ b/arch/arm/mach-imx/imx6.c
> @@ -238,3 +238,42 @@ static int imx6_mmu_init(void)
>  	return 0;
>  }
>  postmmu_initcall(imx6_mmu_init);
> +
> +#define SCU_CONFIG	0x04
> +
> +static int imx6_fixup_cpus(struct device_node *root, void *context)
> +{
> +	struct device_node *cpus_node, *np, *tmp;
> +	unsigned long scu_phys_base;
> +	unsigned int max_core_index;
> +
> +	cpus_node = of_find_node_by_name(root, "cpus");
> +	if (!cpus_node)
> +		return 0;
> +
> +	/* get actual number of available CPU cores from SCU */
> +	asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (scu_phys_base));
> +	max_core_index = (readl(IOMEM(scu_phys_base) + SCU_CONFIG) & 0x03);
> +
> +	for_each_child_of_node_safe(cpus_node, tmp, np) {
> +		u32 cpu_index;
> +
> +		if (of_property_read_u32(np, "reg", &cpu_index))
> +			continue;
> +
> +		if (cpu_index > max_core_index)
> +			of_delete_node(np);
> +	}
> +
> +	return 0;
> +}
> +
> +static int imx6_fixup_cpus_register(void)
> +{
> +	if (!of_machine_is_compatible("fsl,imx6q") &&
> +	    !of_machine_is_compatible("fsl,imx6dl"))
> +		return 0;
> +
> +	return of_register_fixup(imx6_fixup_cpus, NULL);
> +}
> +device_initcall(imx6_fixup_cpus_register);
> -- 
> 2.6.1
> 
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox