Patch adds detection of Zynq-7000 base silicon configuration,
namely Dual or Single CPU. Device trees attempting to enable DUAL CORE
behavior on SINGLE CPU Zynq-7000S devices are prevented from corrupting
system behavior.
Detection of Dual or Single CPU is done via eFuses.
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
Acked-by: Sören Brinkmann <soren.brinkmann@xxxxxxxxxx>
---
arch/arm/boot/dts/zynq-7000.dtsi | 5 +++
arch/arm/mach-zynq/Makefile | 2 +-
arch/arm/mach-zynq/common.c | 1 +
arch/arm/mach-zynq/common.h | 3 ++
arch/arm/mach-zynq/efuse.c | 75 ++++++++++++++++++++++++++++++++++++++++
arch/arm/mach-zynq/platsmp.c | 3 ++
6 files changed, 88 insertions(+), 1 deletion(-)
create mode 100644 arch/arm/mach-zynq/efuse.c
diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi
index f3ac9bfe580e..ac37d46b2eab 100644
--- a/arch/arm/boot/dts/zynq-7000.dtsi
+++ b/arch/arm/boot/dts/zynq-7000.dtsi
@@ -305,6 +305,11 @@
syscon = <&slcr>;
};
+ efuse: efuse@f800d000 {
+ compatible = "xlnx,zynq-efuse";
+ reg = <0xf800d000 0x20>;
+ };
+
global_timer: timer@f8f00200 {
compatible = "arm,cortex-a9-global-timer";
reg = <0xf8f00200 0x20>;
diff --git a/arch/arm/mach-zynq/Makefile b/arch/arm/mach-zynq/Makefile
index b03a97eb7501..1fc2d4b53a5e 100644
--- a/arch/arm/mach-zynq/Makefile
+++ b/arch/arm/mach-zynq/Makefile
@@ -3,5 +3,5 @@
#
# Common support
-obj-y := common.o slcr.o pm.o
+obj-y := common.o efuse.o slcr.o pm.o
obj-$(CONFIG_SMP) += headsmp.o platsmp.o
diff --git a/arch/arm/mach-zynq/common.c b/arch/arm/mach-zynq/common.c
index 6aba9ebf8041..5f28f7220d48 100644
--- a/arch/arm/mach-zynq/common.c
+++ b/arch/arm/mach-zynq/common.c
@@ -182,6 +182,7 @@ static void __init zynq_map_io(void)
static void __init zynq_irq_init(void)
{
+ zynq_early_efuse_init();
zynq_early_slcr_init();
irqchip_init();
}
diff --git a/arch/arm/mach-zynq/common.h b/arch/arm/mach-zynq/common.h
index e771933db7e8..33742c3308e0 100644
--- a/arch/arm/mach-zynq/common.h
+++ b/arch/arm/mach-zynq/common.h
@@ -25,6 +25,9 @@
extern void zynq_slcr_cpu_state_write(int cpu, bool die);
extern u32 zynq_slcr_get_device_id(void);
+extern bool zynq_efuse_cpu_state(int cpu);
+extern int zynq_early_efuse_init(void);
+
#ifdef CONFIG_SMP
extern char zynq_secondary_trampoline;
extern char zynq_secondary_trampoline_jump;
diff --git a/arch/arm/mach-zynq/efuse.c b/arch/arm/mach-zynq/efuse.c
new file mode 100644
index 000000000000..d31a5822ec65
--- /dev/null
+++ b/arch/arm/mach-zynq/efuse.c
@@ -0,0 +1,75 @@
+/*
+ * Xilinx EFUSE driver
+ *
+ * Copyright (c) 2016 Xilinx Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include "common.h"
+
+#define EFUSE_STATUS_OFFSET 0x10
+
+/* 0 means cpu1 is working, 1 means cpu1 is broken */
+#define EFUSE_STATUS_CPU_BIT BIT(7)
+
+void __iomem *zynq_efuse_base;
+
+/**
+ * zynq_efuse_cpu_state - Read/write cpu state
+ * @cpu: cpu number
+ *
+ * Return: true if cpu is running, false if cpu is broken
+ */
+bool zynq_efuse_cpu_state(int cpu)
+{
+ u32 state;
+
+ if (!cpu)
+ return true;
+
+ state = readl(zynq_efuse_base + EFUSE_STATUS_OFFSET);
+ state &= EFUSE_STATUS_CPU_BIT;
+
+ if (!state)
+ return true;
+
+ return false;
+}
+
+/**
+ * zynq_early_efuse_init - Early efuse init function
+ *
+ * Return: 0 on success, negative errno otherwise.
+ *
+ * Called very early during boot from platform code.
+ */
+int __init zynq_early_efuse_init(void)
+{
+ struct device_node *np;
+
+ np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-efuse");
+ if (!np) {
+ pr_err("%s: no efuse node found\n", __func__);
+ BUG();
+ }
+
+ zynq_efuse_base = of_iomap(np, 0);
+ if (!zynq_efuse_base) {
+ pr_err("%s: Unable to map I/O memory\n", __func__);
+ BUG();
+ }
+
+ np->data = (__force void *)zynq_efuse_base;
+
+ pr_info("%s mapped to %p\n", np->name, zynq_efuse_base);
+
+ of_node_put(np);
+
+ return 0;
+}
diff --git a/arch/arm/mach-zynq/platsmp.c b/arch/arm/mach-zynq/platsmp.c
index caa6d5fe9078..3d81e0f2972f 100644
--- a/arch/arm/mach-zynq/platsmp.c
+++ b/arch/arm/mach-zynq/platsmp.c
@@ -89,6 +89,9 @@ int zynq_cpun_start(u32 address, int cpu)
static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
+ if (!zynq_efuse_cpu_state(cpu))
+ return -1;
+
return zynq_cpun_start(__pa_symbol(secondary_startup), cpu);
}
--
1.9.1
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