1 files changed, 128 insertions, 0 deletions
diff --git a/drivers/misc/vexpress_config.c b/drivers/misc/vexpress_config.c
new file mode 100644
index 0000000000..9f5baa5288
--- /dev/null
+++ b/drivers/misc/vexpress_config.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Arm Ltd
+ * Author: Liviu Dudau <liviu.dudau@foss.arm.com>
+ *
+ */
+#include <common.h>
+#include <dm.h>
+#include <dm/read.h>
+#include <asm/io.h>
+#include <linux/delay.h>
+#include <misc.h>
+
+#define SYS_CFGDATA		0xa0
+
+#define SYS_CFGCTRL		0xa4
+#define SYS_CFGCTRL_START	BIT(31)
+#define SYS_CFGCTRL_WRITE	BIT(30)
+
+#define SYS_CFGSTAT		0xa8
+#define SYS_CFGSTAT_ERR		BIT(1)
+#define SYS_CFGSTAT_COMPLETE	BIT(0)
+
+struct vexpress_config_sysreg {
+	phys_addr_t addr;
+	u32 site;
+};
+
+static int vexpress_config_exec(struct vexpress_config_sysreg *syscfg,
+				bool write, void *buf, int size)
+{
+	u32 cmd, status, tries = 100;
+
+	cmd = (*(u32 *)buf) | SYS_CFGCTRL_START | (syscfg->site << 16);
+
+	if (!write) {
+		/* write a canary in the data register for reads */
+		writel(0xdeadbeef, syscfg->addr + SYS_CFGDATA);
+	} else {
+		cmd |= SYS_CFGCTRL_WRITE;
+		writel(((u32 *)buf)[1], syscfg->addr + SYS_CFGDATA);
+	}
+	writel(0, syscfg->addr + SYS_CFGSTAT);
+	writel(cmd, syscfg->addr + SYS_CFGCTRL);
+
+	/* completion of command takes ages, go to sleep (150us) */
+	do {
+		udelay(150);
+		status = readl(syscfg->addr + SYS_CFGSTAT);
+		if (status & SYS_CFGSTAT_ERR)
+			return -EFAULT;
+	} while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
+
+	if (!tries)
+		return -ETIMEDOUT;
+
+	if (!write)
+		(*(u32 *)buf) = readl(syscfg->addr + SYS_CFGDATA);
+
+	return 0;
+}
+
+static int vexpress_config_read(struct udevice *dev,
+				int offset, void *buf, int size)
+{
+	struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev);
+
+	if (size != sizeof(u32))
+		return -EINVAL;
+
+	return vexpress_config_exec(priv, false, buf, size);
+}
+
+static int vexpress_config_write(struct udevice *dev,
+				 int offset, const void *buf, int size)
+{
+	struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev);
+
+	if (size != sizeof(u32) * 2)
+		return -EINVAL;
+
+	return vexpress_config_exec(priv, true, (void *)buf, size);
+}
+
+static struct misc_ops vexpress_config_ops = {
+	.read = vexpress_config_read,
+	.write = vexpress_config_write,
+};
+
+static int vexpress_config_probe(struct udevice *dev)
+{
+	struct ofnode_phandle_args args;
+	struct vexpress_config_sysreg *priv;
+	const char *prop;
+	int err, prop_size;
+
+	err = dev_read_phandle_with_args(dev, "arm,vexpress,config-bridge",
+					 NULL, 0, 0, &args);
+	if (err)
+		return err;
+
+	prop = ofnode_get_property(args.node, "compatible", &prop_size);
+	if (!prop || (strncmp(prop, "arm,vexpress-sysreg", 19) != 0))
+		return -ENOENT;
+
+	priv = calloc(1, sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+
+	dev->uclass_priv = priv;
+	priv->addr = ofnode_get_addr(args.node);
+
+	return dev_read_u32(dev, "arm,vexpress,site", &priv->site);
+}
+
+static const struct udevice_id vexpress_config_ids[] = {
+	{ .compatible = "arm,vexpress,config-bus" },
+	{ }
+};
+
+U_BOOT_DRIVER(vexpress_config_drv) = {
+	.name = "vexpress_config_bus",
+	.id = UCLASS_MISC,
+	.of_match = vexpress_config_ids,
+	.bind = dm_scan_fdt_dev,
+	.probe = vexpress_config_probe,
+	.ops = &vexpress_config_ops,
+};