1 files changed, 85 insertions, 0 deletions
diff --git a/arch/mips/alchemy/common/vss.c b/arch/mips/alchemy/common/vss.c
new file mode 100644
index 000000000..3d0d468d9
--- /dev/null
+++ b/arch/mips/alchemy/common/vss.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Au1300 media block power gating (VSS)
+ *
+ * This is a stop-gap solution until I have the clock framework integration
+ * ready. This stuff here really must be handled transparently when clocks
+ * for various media blocks are enabled/disabled.
+ */
+
+#include <linux/export.h>
+#include <linux/spinlock.h>
+#include <asm/mach-au1x00/au1000.h>
+
+#define VSS_GATE	0x00	/* gate wait timers */
+#define VSS_CLKRST	0x04	/* clock/block control */
+#define VSS_FTR		0x08	/* footers */
+
+#define VSS_ADDR(blk)	(KSEG1ADDR(AU1300_VSS_PHYS_ADDR) + (blk * 0x0c))
+
+static DEFINE_SPINLOCK(au1300_vss_lock);
+
+/* enable a block as outlined in the databook */
+static inline void __enable_block(int block)
+{
+	void __iomem *base = (void __iomem *)VSS_ADDR(block);
+
+	__raw_writel(3, base + VSS_CLKRST);	/* enable clock, assert reset */
+	wmb();
+
+	__raw_writel(0x01fffffe, base + VSS_GATE); /* maximum setup time */
+	wmb();
+
+	/* enable footers in sequence */
+	__raw_writel(0x01, base + VSS_FTR);
+	wmb();
+	__raw_writel(0x03, base + VSS_FTR);
+	wmb();
+	__raw_writel(0x07, base + VSS_FTR);
+	wmb();
+	__raw_writel(0x0f, base + VSS_FTR);
+	wmb();
+
+	__raw_writel(0x01ffffff, base + VSS_GATE); /* start FSM too */
+	wmb();
+
+	__raw_writel(2, base + VSS_CLKRST);	/* deassert reset */
+	wmb();
+
+	__raw_writel(0x1f, base + VSS_FTR);	/* enable isolation cells */
+	wmb();
+}
+
+/* disable a block as outlined in the databook */
+static inline void __disable_block(int block)
+{
+	void __iomem *base = (void __iomem *)VSS_ADDR(block);
+
+	__raw_writel(0x0f, base + VSS_FTR);	/* disable isolation cells */
+	wmb();
+	__raw_writel(0, base + VSS_GATE);	/* disable FSM */
+	wmb();
+	__raw_writel(3, base + VSS_CLKRST);	/* assert reset */
+	wmb();
+	__raw_writel(1, base + VSS_CLKRST);	/* disable clock */
+	wmb();
+	__raw_writel(0, base + VSS_FTR);	/* disable all footers */
+	wmb();
+}
+
+void au1300_vss_block_control(int block, int enable)
+{
+	unsigned long flags;
+
+	if (alchemy_get_cputype() != ALCHEMY_CPU_AU1300)
+		return;
+
+	/* only one block at a time */
+	spin_lock_irqsave(&au1300_vss_lock, flags);
+	if (enable)
+		__enable_block(block);
+	else
+		__disable_block(block);
+	spin_unlock_irqrestore(&au1300_vss_lock, flags);
+}
+EXPORT_SYMBOL_GPL(au1300_vss_block_control);