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Diffstat (limited to 'arch/arm/mach-prima2/rstc.c')
-rw-r--r--arch/arm/mach-prima2/rstc.c69
1 files changed, 69 insertions, 0 deletions
diff --git a/arch/arm/mach-prima2/rstc.c b/arch/arm/mach-prima2/rstc.c
new file mode 100644
index 000000000000..d074786e83d4
--- /dev/null
+++ b/arch/arm/mach-prima2/rstc.c
@@ -0,0 +1,69 @@
+/*
+ * reset controller for CSR SiRFprimaII
+ *
+ * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2 or later.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+void __iomem *sirfsoc_rstc_base;
+static DEFINE_MUTEX(rstc_lock);
+
+static struct of_device_id rstc_ids[] = {
+ { .compatible = "sirf,prima2-rstc" },
+};
+
+static int __init sirfsoc_of_rstc_init(void)
+{
+ struct device_node *np;
+
+ np = of_find_matching_node(NULL, rstc_ids);
+ if (!np)
+ panic("unable to find compatible rstc node in dtb\n");
+
+ sirfsoc_rstc_base = of_iomap(np, 0);
+ if (!sirfsoc_rstc_base)
+ panic("unable to map rstc cpu registers\n");
+
+ of_node_put(np);
+
+ return 0;
+}
+early_initcall(sirfsoc_of_rstc_init);
+
+int sirfsoc_reset_device(struct device *dev)
+{
+ const unsigned int *prop = of_get_property(dev->of_node, "reset-bit", NULL);
+ unsigned int reset_bit;
+
+ if (!prop)
+ return -ENODEV;
+
+ reset_bit = be32_to_cpup(prop);
+
+ mutex_lock(&rstc_lock);
+
+ /*
+ * Writing 1 to this bit resets corresponding block. Writing 0 to this
+ * bit de-asserts reset signal of the corresponding block.
+ * datasheet doesn't require explicit delay between the set and clear
+ * of reset bit. it could be shorter if tests pass.
+ */
+ writel(readl(sirfsoc_rstc_base + (reset_bit / 32) * 4) | reset_bit,
+ sirfsoc_rstc_base + (reset_bit / 32) * 4);
+ msleep(10);
+ writel(readl(sirfsoc_rstc_base + (reset_bit / 32) * 4) & ~reset_bit,
+ sirfsoc_rstc_base + (reset_bit / 32) * 4);
+
+ mutex_unlock(&rstc_lock);
+
+ return 0;
+}