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path: root/drivers/soc/mediatek/mtk-infracfg.c
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Diffstat (limited to 'drivers/soc/mediatek/mtk-infracfg.c')
-rw-r--r--drivers/soc/mediatek/mtk-infracfg.c91
1 files changed, 91 insertions, 0 deletions
diff --git a/drivers/soc/mediatek/mtk-infracfg.c b/drivers/soc/mediatek/mtk-infracfg.c
new file mode 100644
index 000000000..dba3055a9
--- /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;
+}