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From: Lucas Stach <l.stach@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH] ARM: imx6: add OF fixup to delete nonexistent CPU cores
Date: Mon, 26 Oct 2015 17:33:49 +0100	[thread overview]
Message-ID: <1445877229-14319-1-git-send-email-l.stach@pengutronix.de> (raw)

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>
---
 arch/arm/mach-imx/imx6.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/arch/arm/mach-imx/imx6.c b/arch/arm/mach-imx/imx6.c
index c49de49209f3..c2a4d62c51da 100644
--- a/arch/arm/mach-imx/imx6.c
+++ b/arch/arm/mach-imx/imx6.c
@@ -238,3 +238,37 @@ 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) {
+	return of_register_fixup(imx6_fixup_cpus, NULL);
+}
+device_initcall(imx6_fixup_cpus_register);
-- 
2.6.1


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             reply	other threads:[~2015-10-26 16:34 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-26 16:33 Lucas Stach [this message]
2015-10-27 14:43 ` Sascha Hauer
2015-10-27 14:45   ` Lucas Stach

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