1 files changed, 145 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/mmio_nvram.c b/arch/powerpc/sysdev/mmio_nvram.c
new file mode 100644
index 000000000..eb48210ef
--- /dev/null
+++ b/arch/powerpc/sysdev/mmio_nvram.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * memory mapped NVRAM
+ *
+ * (C) Copyright IBM Corp. 2005
+ *
+ * Authors : Utz Bacher <utz.bacher@de.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include <asm/machdep.h>
+#include <asm/nvram.h>
+
+static void __iomem *mmio_nvram_start;
+static long mmio_nvram_len;
+static DEFINE_SPINLOCK(mmio_nvram_lock);
+
+static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
+{
+	unsigned long flags;
+
+	if (*index >= mmio_nvram_len)
+		return 0;
+	if (*index + count > mmio_nvram_len)
+		count = mmio_nvram_len - *index;
+
+	spin_lock_irqsave(&mmio_nvram_lock, flags);
+
+	memcpy_fromio(buf, mmio_nvram_start + *index, count);
+
+	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
+	
+	*index += count;
+	return count;
+}
+
+static unsigned char mmio_nvram_read_val(int addr)
+{
+	unsigned long flags;
+	unsigned char val;
+
+	if (addr >= mmio_nvram_len)
+		return 0xff;
+
+	spin_lock_irqsave(&mmio_nvram_lock, flags);
+
+	val = ioread8(mmio_nvram_start + addr);
+
+	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
+
+	return val;
+}
+
+static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
+{
+	unsigned long flags;
+
+	if (*index >= mmio_nvram_len)
+		return 0;
+	if (*index + count > mmio_nvram_len)
+		count = mmio_nvram_len - *index;
+
+	spin_lock_irqsave(&mmio_nvram_lock, flags);
+
+	memcpy_toio(mmio_nvram_start + *index, buf, count);
+
+	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
+	
+	*index += count;
+	return count;
+}
+
+static void mmio_nvram_write_val(int addr, unsigned char val)
+{
+	unsigned long flags;
+
+	if (addr < mmio_nvram_len) {
+		spin_lock_irqsave(&mmio_nvram_lock, flags);
+
+		iowrite8(val, mmio_nvram_start + addr);
+
+		spin_unlock_irqrestore(&mmio_nvram_lock, flags);
+	}
+}
+
+static ssize_t mmio_nvram_get_size(void)
+{
+	return mmio_nvram_len;
+}
+
+int __init mmio_nvram_init(void)
+{
+	struct device_node *nvram_node;
+	unsigned long nvram_addr;
+	struct resource r;
+	int ret;
+
+	nvram_node = of_find_node_by_type(NULL, "nvram");
+	if (!nvram_node)
+		nvram_node = of_find_compatible_node(NULL, NULL, "nvram");
+	if (!nvram_node) {
+		printk(KERN_WARNING "nvram: no node found in device-tree\n");
+		return -ENODEV;
+	}
+
+	ret = of_address_to_resource(nvram_node, 0, &r);
+	if (ret) {
+		printk(KERN_WARNING "nvram: failed to get address (err %d)\n",
+		       ret);
+		goto out;
+	}
+	nvram_addr = r.start;
+	mmio_nvram_len = resource_size(&r);
+	if ( (!mmio_nvram_len) || (!nvram_addr) ) {
+		printk(KERN_WARNING "nvram: address or length is 0\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
+	if (!mmio_nvram_start) {
+		printk(KERN_WARNING "nvram: failed to ioremap\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
+	       mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start);
+
+	ppc_md.nvram_read_val	= mmio_nvram_read_val;
+	ppc_md.nvram_write_val	= mmio_nvram_write_val;
+	ppc_md.nvram_read	= mmio_nvram_read;
+	ppc_md.nvram_write	= mmio_nvram_write;
+	ppc_md.nvram_size	= mmio_nvram_get_size;
+
+out:
+	of_node_put(nvram_node);
+	return ret;
+}