[v2,1/5] drivers: soc: sunxi: Introduce SoC driver to map SRAMs

diff --git a/Documentation/devicetree/bindings/soc/sunxi/sram.txt b/Documentation/devicetree/bindings/soc/sunxi/sram.txt
new file mode 100644
index 0000000..bd3e53d
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/sunxi/sram.txt
@@ -0,0 +1,64 @@ 
+Allwinnner sun4i / sun5i / sun7i SoC SRAM controllers
+-----------------------------------------------------
+
+Required properties:
+- compatible : "allwinner,sun4i-a10-sram-controller"
+- reg : sram controller register offset + length
+
+SRAM nodes
+----------
+
+Besides a node for the SRAM controller the devicetree must also contain a
+node for each SRAM block controlled by the controller.
+
+Required sram node properties:
+- compatible : "allwinner,sun4i-a10-sram"
+- allwinner,sram-name : should be one of
+  * "A1"
+  * "A2"
+  * "A3-A4"
+  * "D"
+
+Example
+-------
+
+/*
+ * Note we use the address where the mmio registers start, not where
+ * the SRAM blocks start, this cannot be changed because that would be
+ * a devicetree ABI change.
+ */
+soc@01c00000 {
+	compatible = "simple-bus";
+	#address-cells = <1>;
+	#size-cells = <1>;
+	ranges;
+
+	sram@00000000 {
+		compatible = "allwinner,sun4i-a10-sram";
+		reg = <0x00000000 0x4000>;
+		allwinner,sram-name = "A1";
+	};
+
+	sram@00004000 {
+		compatible = "allwinner,sun4i-a10-sram";
+		reg = <0x00004000 0x4000>;
+		allwinner,sram-name = "A2";
+	};
+
+	sram@00008000 {
+		compatible = "allwinner,sun4i-a10-sram";
+		reg = <0x00008000 0x4000>;
+		allwinner,sram-name = "A3-A4";
+	};
+
+	sram@00010000 {
+		compatible = "allwinner,sun4i-a10-sram";
+		reg = <0x00010000 0x1000>;
+		allwinner,sram-name = "D";
+	};
+
+	sram-controller@01c00000 {
+		compatible = "allwinner,sun4i-a10-sram-controller";
+		reg = <0x01c00000 0x30>;
+	};
+};
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 76d6bd4..5d0f55d 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -1,6 +1,7 @@ 
 menu "SOC (System On Chip) specific Drivers"
 
 source "drivers/soc/qcom/Kconfig"
+source "drivers/soc/sunxi/Kconfig"
 source "drivers/soc/ti/Kconfig"
 source "drivers/soc/versatile/Kconfig"
 
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 063113d..170bba3 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -3,6 +3,7 @@ 
 #
 
 obj-$(CONFIG_ARCH_QCOM)		+= qcom/
+obj-$(CONFIG_ARCH_SUNXI)	+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-$(CONFIG_SOC_TI)		+= ti/
 obj-$(CONFIG_PLAT_VERSATILE)	+= versatile/
diff --git a/drivers/soc/sunxi/Kconfig b/drivers/soc/sunxi/Kconfig
new file mode 100644
index 0000000..e6de9fe
--- /dev/null
+++ b/drivers/soc/sunxi/Kconfig
@@ -0,0 +1,11 @@ 
+#
+# Allwinner sunXi SoC drivers
+#
+config SUNXI_SRAM
+	boolean
+	depends on ARCH_SUNXI
+	default y
+	help
+	  Say y here to enable the SRAM controller support. This
+	  device is responsible on mapping the SRAM in the sunXi SoCs
+	  whether to the CPU/DMA, or to the devices.
diff --git a/drivers/soc/sunxi/Makefile b/drivers/soc/sunxi/Makefile
new file mode 100644
index 0000000..4cf9dbd
--- /dev/null
+++ b/drivers/soc/sunxi/Makefile
@@ -0,0 +1 @@ 
+obj-$(CONFIG_SUNXI_SRAM) +=	sunxi_sram.o
diff --git a/drivers/soc/sunxi/sunxi_sram.c b/drivers/soc/sunxi/sunxi_sram.c
new file mode 100644
index 0000000..5b76fd1
--- /dev/null
+++ b/drivers/soc/sunxi/sunxi_sram.c
@@ -0,0 +1,235 @@ 
+/*
+ * Allwinner SoCs SRAM Controller Driver
+ *
+ * Copyright (C) 2015 Maxime Ripard
+ *
+ * Author: Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#include <linux/soc/sunxi/sunxi_sram.h>
+
+struct sunxi_sram_func {
+	char	*func;
+	u8	val;
+};
+
+struct sunxi_sram_desc {
+	enum sunxi_sram_type	type;
+	char			*name;
+	u8			reg;
+	u8			offset;
+	u8			width;
+	struct sunxi_sram_func	*func;
+	bool			claimed;
+	bool			enabled;
+};
+
+#define SUNXI_SRAM_MAP(_val, _func)				\
+	{							\
+		.func = _func,					\
+		.val = _val,					\
+	}
+
+#define SUNXI_SRAM_DESC(_type, _name, _reg, _off, _width, ...)	\
+	{							\
+		.type = _type,					\
+		.name = _name,					\
+		.reg = _reg,					\
+		.offset = _off,					\
+		.width = _width,				\
+		.func = (struct sunxi_sram_func[]){		\
+			__VA_ARGS__, { } },			\
+	}
+
+struct sunxi_sram_desc sun4i_sram_desc[] = {
+	SUNXI_SRAM_DESC(SUNXI_SRAM_EMAC, "A3-A4", 0x4, 0x4, 1,
+			SUNXI_SRAM_MAP(0, "cpu"),
+			SUNXI_SRAM_MAP(1, "emac")),
+	SUNXI_SRAM_DESC(SUNXI_SRAM_USB_OTG, "D", 0x4, 0x0, 1,
+			SUNXI_SRAM_MAP(0, "cpu"),
+			SUNXI_SRAM_MAP(1, "usb-otg")),
+	{ /* Sentinel */ },
+};
+
+static struct sunxi_sram_desc *sram_list;
+static DEFINE_SPINLOCK(sram_lock);
+static void __iomem *base;
+
+static int sunxi_sram_show(struct seq_file *s, void *data)
+{
+	struct sunxi_sram_desc *sram;
+	struct sunxi_sram_func *func;
+	u32 val;
+
+	seq_puts(s, "Allwinner sunXi SRAM\n");
+	seq_puts(s, "--------------------\n");
+
+
+	for (sram = sram_list; sram->name; sram++) {
+		if (!sram->enabled)
+			continue;
+
+		seq_printf(s, "\n%s\n", sram->name);
+
+		val = readl(base + sram->reg);
+		val >>= sram->offset;
+		val &= sram->width;
+
+		for (func = sram->func; func->func; func++) {
+			seq_printf(s, "\t\t%s%c\n", func->func,
+				   func->val == val ? '*' : ' ');
+		}
+	}
+
+	return 0;
+}
+
+static int sunxi_sram_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, sunxi_sram_show, inode->i_private);
+}
+
+static const struct file_operations sunxi_sram_fops = {
+	.open = sunxi_sram_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+int sunxi_sram_claim(enum sunxi_sram_type type, const char *function)
+{
+	struct sunxi_sram_desc *sram;
+	struct sunxi_sram_func *func;
+	u32 val;
+
+	if (IS_ERR(base))
+		return -EPROBE_DEFER;
+
+	for (sram = sram_list; sram->name; sram++) {
+		if (sram->type != type)
+			continue;
+
+		if (!sram->enabled)
+			return -ENODEV;
+
+		spin_lock(&sram_lock);
+
+		if (sram->claimed) {
+			spin_unlock(&sram_lock);
+			return -EBUSY;
+		}
+
+		sram->claimed = true;
+		spin_unlock(&sram_lock);
+
+		for (func = sram->func; func->func; func++) {
+			if (strcmp(function, func->func))
+				continue;
+
+			val = readl(base + sram->reg);
+			val &= ~GENMASK(sram->offset + sram->width,
+					sram->offset);
+			writel(val | func->val, base + sram->reg);
+
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(sunxi_sram_claim);
+
+int sunxi_sram_release(enum sunxi_sram_type type)
+{
+	struct sunxi_sram_desc *sram;
+
+	for (sram = sram_list; sram->type; sram++) {
+		if (sram->type != type)
+			continue;
+
+		if (!sram->enabled)
+			return -ENODEV;
+
+		spin_lock(&sram_lock);
+		sram->claimed = false;
+		spin_unlock(&sram_lock);
+
+		return 0;
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(sunxi_sram_release);
+
+static const struct of_device_id sunxi_sram_dt_match[] = {
+	{ .compatible = "allwinner,sun4i-a10-sram-controller",
+	  .data = &sun4i_sram_desc },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sunxi_sram_dt_match);
+
+static int sunxi_sram_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	struct sunxi_sram_desc *sram;
+	struct device_node *node;
+	struct resource *res;
+	struct dentry *d;
+	const char *name;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	match = of_match_device(sunxi_sram_dt_match, &pdev->dev);
+	if (!match)
+		return -ENODEV;
+
+	sram_list = (struct sunxi_sram_desc *)match->data;
+
+	for_each_compatible_node(node, NULL, "allwinner,sun4i-a10-sram") {
+		if (of_property_read_string(node, "allwinner,sram-name", &name))
+			continue;
+
+		for (sram = sram_list; sram->name; sram++)
+			if (!strcmp(name, sram->name))
+				break;
+
+		if (!sram->name)
+			continue;
+
+		sram->enabled = true;
+	}
+
+	d = debugfs_create_file("sram", S_IRUGO, NULL, NULL,
+				&sunxi_sram_fops);
+	if (!d)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static struct platform_driver sunxi_sram_driver = {
+	.driver = {
+		.name		= "sunxi-sram",
+		.of_match_table	= sunxi_sram_dt_match,
+	},
+	.probe	= sunxi_sram_probe,
+};
+module_platform_driver(sunxi_sram_driver);
+
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner sunXi SRAM Controller Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/soc/sunxi/sunxi_sram.h b/include/linux/soc/sunxi/sunxi_sram.h
new file mode 100644
index 0000000..351c31a
--- /dev/null
+++ b/include/linux/soc/sunxi/sunxi_sram.h
@@ -0,0 +1,24 @@ 
+/*
+ * Allwinner SoCs SRAM Controller Driver
+ *
+ * Copyright (C) 2015 Maxime Ripard
+ *
+ * Author: Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _SUNXI_SRAM_H_
+#define _SUNXI_SRAM_H_
+
+enum sunxi_sram_type {
+	SUNXI_SRAM_USB_OTG,
+	SUNXI_SRAM_EMAC,
+};
+
+int sunxi_sram_claim(enum sunxi_sram_type type, const char *function);
+int sunxi_sram_release(enum sunxi_sram_type type);
+
+#endif /* _SUNXI_SRAM_H_ */