1 files changed, 267 insertions, 0 deletions
diff --git a/arch/sh/drivers/dma/dma-sh.c b/arch/sh/drivers/dma/dma-sh.c
new file mode 100644
index 0000000..31dacd4
--- /dev/null
+++ b/arch/sh/drivers/dma/dma-sh.c
@@ -0,0 +1,267 @@
+/*
+ * arch/sh/drivers/dma/dma-sh.c
+ *
+ * SuperH On-chip DMAC Support
+ *
+ * Copyright (C) 2000 Takashi YOSHII
+ * Copyright (C) 2003, 2004 Paul Mundt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <asm/signal.h>
+#include <asm/irq.h>
+#include <asm/dma.h>
+#include <asm/io.h>
+#include "dma-sh.h"
+
+/*
+ * The SuperH DMAC supports a number of transmit sizes, we list them here,
+ * with their respective values as they appear in the CHCR registers.
+ *
+ * Defaults to a 64-bit transfer size.
+ */
+enum {
+	XMIT_SZ_64BIT,
+	XMIT_SZ_8BIT,
+	XMIT_SZ_16BIT,
+	XMIT_SZ_32BIT,
+	XMIT_SZ_256BIT,
+};
+
+/*
+ * The DMA count is defined as the number of bytes to transfer.
+ */
+static unsigned int ts_shift[] = {
+	[XMIT_SZ_64BIT]		= 3,
+	[XMIT_SZ_8BIT]		= 0,
+	[XMIT_SZ_16BIT]		= 1,
+	[XMIT_SZ_32BIT]		= 2,
+	[XMIT_SZ_256BIT]	= 5,
+};
+
+static inline unsigned int get_dmte_irq(unsigned int chan)
+{
+	unsigned int irq;
+
+	/*
+	 * Normally we could just do DMTE0_IRQ + chan outright, though in the
+	 * case of the 7751R, the DMTE IRQs for channels > 4 start right above
+	 * the SCIF
+	 */
+
+	if (chan < 4) {
+		irq = DMTE0_IRQ + chan;
+	} else {
+		irq = DMTE4_IRQ + chan - 4;
+	}
+
+	return irq;
+}
+
+/*
+ * We determine the correct shift size based off of the CHCR transmit size
+ * for the given channel. Since we know that it will take:
+ *
+ *	info->count >> ts_shift[transmit_size]
+ *
+ * iterations to complete the transfer.
+ */
+static inline unsigned int calc_xmit_shift(struct dma_channel *chan)
+{
+	u32 chcr = ctrl_inl(CHCR[chan->chan]);
+
+	chcr >>= 4;
+
+	return ts_shift[chcr & 0x0007];
+}
+
+/*
+ * The transfer end interrupt must read the chcr register to end the
+ * hardware interrupt active condition.
+ * Besides that it needs to waken any waiting process, which should handle
+ * setting up the next transfer.
+ */
+static irqreturn_t dma_tei(int irq, void *dev_id, struct pt_regs *regs)
+{
+	struct dma_channel *chan = (struct dma_channel *)dev_id;
+	u32 chcr;
+
+	chcr = ctrl_inl(CHCR[chan->chan]);
+
+	if (!(chcr & CHCR_TE))
+		return IRQ_NONE;
+
+	chcr &= ~(CHCR_IE | CHCR_DE);
+	ctrl_outl(chcr, CHCR[chan->chan]);
+
+	wake_up(&chan->wait_queue);
+
+	return IRQ_HANDLED;
+}
+
+static int sh_dmac_request_dma(struct dma_channel *chan)
+{
+	return request_irq(get_dmte_irq(chan->chan), dma_tei,
+			   SA_INTERRUPT, "DMAC Transfer End", chan);
+}
+
+static void sh_dmac_free_dma(struct dma_channel *chan)
+{
+	free_irq(get_dmte_irq(chan->chan), chan);
+}
+
+static void sh_dmac_configure_channel(struct dma_channel *chan, unsigned long chcr)
+{
+	if (!chcr)
+		chcr = RS_DUAL;
+
+	ctrl_outl(chcr, CHCR[chan->chan]);
+
+	chan->flags |= DMA_CONFIGURED;
+}
+
+static void sh_dmac_enable_dma(struct dma_channel *chan)
+{
+	int irq = get_dmte_irq(chan->chan);
+	u32 chcr;
+
+	chcr = ctrl_inl(CHCR[chan->chan]);
+	chcr |= CHCR_DE | CHCR_IE;
+	ctrl_outl(chcr, CHCR[chan->chan]);
+
+	enable_irq(irq);
+}
+
+static void sh_dmac_disable_dma(struct dma_channel *chan)
+{
+	int irq = get_dmte_irq(chan->chan);
+	u32 chcr;
+
+	disable_irq(irq);
+
+	chcr = ctrl_inl(CHCR[chan->chan]);
+	chcr &= ~(CHCR_DE | CHCR_TE | CHCR_IE);
+	ctrl_outl(chcr, CHCR[chan->chan]);
+}
+
+static int sh_dmac_xfer_dma(struct dma_channel *chan)
+{
+	/*
+	 * If we haven't pre-configured the channel with special flags, use
+	 * the defaults.
+	 */
+	if (!(chan->flags & DMA_CONFIGURED))
+		sh_dmac_configure_channel(chan, 0);
+
+	sh_dmac_disable_dma(chan);
+
+	/*
+	 * Single-address mode usage note!
+	 *
+	 * It's important that we don't accidentally write any value to SAR/DAR
+	 * (this includes 0) that hasn't been directly specified by the user if
+	 * we're in single-address mode.
+	 *
+	 * In this case, only one address can be defined, anything else will
+	 * result in a DMA address error interrupt (at least on the SH-4),
+	 * which will subsequently halt the transfer.
+	 *
+	 * Channel 2 on the Dreamcast is a special case, as this is used for
+	 * cascading to the PVR2 DMAC. In this case, we still need to write
+	 * SAR and DAR, regardless of value, in order for cascading to work.
+	 */
+	if (chan->sar || (mach_is_dreamcast() && chan->chan == 2))
+		ctrl_outl(chan->sar, SAR[chan->chan]);
+	if (chan->dar || (mach_is_dreamcast() && chan->chan == 2))
+		ctrl_outl(chan->dar, DAR[chan->chan]);
+
+	ctrl_outl(chan->count >> calc_xmit_shift(chan), DMATCR[chan->chan]);
+
+	sh_dmac_enable_dma(chan);
+
+	return 0;
+}
+
+static int sh_dmac_get_dma_residue(struct dma_channel *chan)
+{
+	if (!(ctrl_inl(CHCR[chan->chan]) & CHCR_DE))
+		return 0;
+
+	return ctrl_inl(DMATCR[chan->chan]) << calc_xmit_shift(chan);
+}
+
+#if defined(CONFIG_CPU_SH4)
+static irqreturn_t dma_err(int irq, void *dev_id, struct pt_regs *regs)
+{
+	unsigned long dmaor = ctrl_inl(DMAOR);
+
+	printk("DMAE: DMAOR=%lx\n", dmaor);
+
+	ctrl_outl(ctrl_inl(DMAOR)&~DMAOR_NMIF, DMAOR);
+	ctrl_outl(ctrl_inl(DMAOR)&~DMAOR_AE, DMAOR);
+	ctrl_outl(ctrl_inl(DMAOR)|DMAOR_DME, DMAOR);
+
+	disable_irq(irq);
+
+	return IRQ_HANDLED;
+}
+#endif
+
+static struct dma_ops sh_dmac_ops = {
+	.request	= sh_dmac_request_dma,
+	.free		= sh_dmac_free_dma,
+	.get_residue	= sh_dmac_get_dma_residue,
+	.xfer		= sh_dmac_xfer_dma,
+	.configure	= sh_dmac_configure_channel,
+};
+
+static struct dma_info sh_dmac_info = {
+	.name		= "SuperH DMAC",
+	.nr_channels	= 4,
+	.ops		= &sh_dmac_ops,
+	.flags		= DMAC_CHANNELS_TEI_CAPABLE,
+};
+
+static int __init sh_dmac_init(void)
+{
+	struct dma_info *info = &sh_dmac_info;
+	int i;
+
+#ifdef CONFIG_CPU_SH4
+	make_ipr_irq(DMAE_IRQ, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY);
+	i = request_irq(DMAE_IRQ, dma_err, SA_INTERRUPT, "DMAC Address Error", 0);
+	if (i < 0)
+		return i;
+#endif
+
+	for (i = 0; i < info->nr_channels; i++) {
+		int irq = get_dmte_irq(i);
+
+		make_ipr_irq(irq, DMA_IPR_ADDR, DMA_IPR_POS, DMA_PRIORITY);
+	}
+
+	ctrl_outl(0x8000 | DMAOR_DME, DMAOR);
+
+	return register_dmac(info);
+}
+
+static void __exit sh_dmac_exit(void)
+{
+#ifdef CONFIG_CPU_SH4
+	free_irq(DMAE_IRQ, 0);
+#endif
+}
+
+subsys_initcall(sh_dmac_init);
+module_exit(sh_dmac_exit);
+
+MODULE_LICENSE("GPL");
+