[PATCH 1/5] soc: mediatek: Add infracfg misc driver support

[Sascha Hauer]

This adds support for some miscellaneous bits of the infracfg controller.
The mtk_infracfg_set/clear_bus_protection functions are necessary for
the scpsys power domain driver to handle the bus protection bits which
are contained in the infacfg register space.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 drivers/soc/mediatek/Kconfig        |  9 +++++
 drivers/soc/mediatek/Makefile       |  1 +
 drivers/soc/mediatek/mtk-infracfg.c | 80 +++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 drivers/soc/mediatek/mtk-infracfg.c

diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
index bcdb22d..6fae66f 100644
--- a/drivers/soc/mediatek/Kconfig
+++ b/drivers/soc/mediatek/Kconfig
@@ -9,3 +9,12 @@ config MTK_PMIC_WRAP
 	  Say yes here to add support for MediaTek PMIC Wrapper found
 	  on different MediaTek SoCs. The PMIC wrapper is a proprietary
 	  hardware to connect the PMIC.
+
+config MTK_INFRACFG
+	tristate "MediaTek INFRACFG Support"
+	depends on ARCH_MEDIATEK
+	select REGMAP
+	help
+	  Say yes here to add support for the MediaTek INFRACFG controller. The
+	  INFRACFG controller contains various infrastructure registers not
+	  directly associated to any device.
diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
index ecaf4de..ce39119 100644
--- a/drivers/soc/mediatek/Makefile
+++ b/drivers/soc/mediatek/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
+obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
diff --git a/drivers/soc/mediatek/mtk-infracfg.c b/drivers/soc/mediatek/mtk-infracfg.c
new file mode 100644
index 0000000..b3ebfae
--- /dev/null
+++ b/drivers/soc/mediatek/mtk-infracfg.c
@@ -0,0 +1,80 @@
+#include <linux/regmap.h>
+#include <linux/export.h>
+#include <linux/jiffies.h>
+#include <linux/soc/mediatek/infracfg.h>
+#include <asm/processor.h>
+
+#define INFRA_TOPAXI_PROTECTEN		0x0220
+#define INFRA_TOPAXI_PROTECTSTA1	0x0228
+
+/**
+ * mtk_infracfg_set_bus_protection - enable bus protection
+ * @regmap: The infracfg regmap
+ * @mask: The mask containing the protection bits to be enabled.
+ *
+ * This function enables the bus protection bits for disabled power
+ * domains so that the system does not hanf when some unit accesses the
+ * bus while in power down.
+ */
+int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask)
+{
+	unsigned long expired;
+	u32 val;
+	int ret;
+
+	regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, mask);
+
+	expired = jiffies + HZ;
+
+	while (1) {
+		ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
+		if (ret)
+			return ret;
+
+		if ((val & mask) == mask)
+			break;
+
+		cpu_relax();
+		if (time_after(jiffies, expired))
+			return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtk_infracfg_set_bus_protection);
+
+/**
+ * mtk_infracfg_clear_bus_protection - disable bus protection
+ * @regmap: The infracfg regmap
+ * @mask: The mask containing the protection bits to be disabled.
+ *
+ * This function disables the bus protection bits previously enabled with
+ * mtk_infracfg_set_bus_protection.
+ */
+int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask)
+{
+	unsigned long expired;
+	int ret;
+
+	regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, 0);
+
+	expired = jiffies + HZ;
+
+	while (1) {
+		u32 val;
+
+		ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
+		if (ret)
+			return ret;
+
+		if (!(val & mask))
+			break;
+
+		cpu_relax();
+		if (time_after(jiffies, expired))
+			return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtk_infracfg_clear_bus_protection);
-- 
2.1.4