soc: mediatek: Add infracfg misc driver support

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@pengutronix.de>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

3 files changed, 101 insertions, 0 deletions

diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
index 3c1850332a90..e609a6f5e2eb 100644
--- a/drivers/soc/mediatek/Kconfig
+++ b/drivers/soc/mediatek/Kconfig
@@ -1,6 +1,15 @@
 #
 # MediaTek SoC drivers
 #
+config MTK_INFRACFG
+        bool "MediaTek INFRACFG Support"
+        depends on ARCH_MEDIATEK || COMPILE_TEST
+        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.
+
 config MTK_PMIC_WRAP
         tristate "MediaTek PMIC Wrapper Support"
         depends on ARCH_MEDIATEK
diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
index ecaf4defd7f6..3fa940fb4eab 100644
--- a/drivers/soc/mediatek/Makefile
+++ b/drivers/soc/mediatek/Makefile
@@ -1 +1,2 @@
+obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
 obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
diff --git a/drivers/soc/mediatek/mtk-infracfg.c b/drivers/soc/mediatek/mtk-infracfg.c
new file mode 100644
index 000000000000..dba3055a9493
--- /dev/null
+++ b/drivers/soc/mediatek/mtk-infracfg.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/jiffies.h>
+#include <linux/regmap.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 hang 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;
+}
+
+/**
+ * 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;
+}