Initial commit

arch/arm/mach-spear/pl080.c

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+/*
+ * arch/arm/plat-spear/pl080.c
+ *
+ * DMAC pl080 definitions for SPEAr platform
+ *
+ * Copyright (C) 2012 ST Microelectronics
+ * Viresh Kumar <viresh.linux@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/amba/pl08x.h>
+#include <linux/amba/bus.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/spinlock_types.h>
+#include <mach/spear.h>
+#include <mach/misc_regs.h>
+
+static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);
+
+struct {
+	unsigned char busy;
+	unsigned char val;
+} signals[16] = {{0, 0}, };
+
+int pl080_get_signal(const struct pl08x_channel_data *cd)
+{
+	unsigned int signal = cd->min_signal, val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&lock, flags);
+
+	/* Return if signal is already acquired by somebody else */
+	if (signals[signal].busy &&
+			(signals[signal].val != cd->muxval)) {
+		spin_unlock_irqrestore(&lock, flags);
+		return -EBUSY;
+	}
+
+	/* If acquiring for the first time, configure it */
+	if (!signals[signal].busy) {
+		val = readl(DMA_CHN_CFG);
+
+		/*
+		 * Each request line has two bits in DMA_CHN_CFG register. To
+		 * goto the bits of current request line, do left shift of
+		 * value by 2 * signal number.
+		 */
+		val &= ~(0x3 << (signal * 2));
+		val |= cd->muxval << (signal * 2);
+		writel(val, DMA_CHN_CFG);
+	}
+
+	signals[signal].busy++;
+	signals[signal].val = cd->muxval;
+	spin_unlock_irqrestore(&lock, flags);
+
+	return signal;
+}
+
+void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&lock, flags);
+
+	/* if signal is not used */
+	if (!signals[signal].busy)
+		BUG();
+
+	signals[signal].busy--;
+
+	spin_unlock_irqrestore(&lock, flags);
+}