[ARM] 3444/1: i.MX: Scatter-gather DMA emulation for i.MX/MX1

Patch from Pavel Pisa

This patch contains simplified set of changes to add scatter-gather
emulation capability into MX1 DMA support. The result should
be still usable for next combination of DMA transfers
  Statter-Gather/linear/2D/FIFO to linear/2D/FIFO and
  linear/2D/FIFO to Statter-Gather/2D/FIFO
The patch corrects channel priority allocation to be compatible
with MX1 hardware implementation.
Previous code has not been adapted from its PXA original.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/asm-arm/arch-imx/dma.h

@@ -17,27 +17,16 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
+
 #ifndef __ASM_ARCH_DMA_H
 #define __ASM_ARCH_DMA_H
 
-/*
- * DMA registration
- */
-
 typedef enum {
 	DMA_PRIO_HIGH = 0,
-	DMA_PRIO_MEDIUM = 3,
-	DMA_PRIO_LOW = 6
+	DMA_PRIO_MEDIUM = 1,
+	DMA_PRIO_LOW = 2
 } imx_dma_prio;
 
-int imx_request_dma(char *name, imx_dma_prio prio,
-		    void (*irq_handler) (int, void *, struct pt_regs *),
-		    void (*err_handler) (int, void *, struct pt_regs *),
-		    void *data);
-
-void imx_free_dma(int dma_ch);
-
-
 #define DMA_REQ_UART3_T        2
 #define DMA_REQ_UART3_R        3
 #define DMA_REQ_SSI2_T         4

include/asm-arm/arch-imx/imx-dma.h

+/*
+ *  linux/include/asm-arm/imxads/dma.h
+ *
+ *  Copyright (C) 1997,1998 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <asm/dma.h>
+
+#ifndef __ASM_ARCH_IMX_DMA_H
+#define __ASM_ARCH_IMX_DMA_H
+
+#define IMX_DMA_CHANNELS  11
+
+/*
+ * struct imx_dma_channel - i.MX specific DMA extension
+ * @name: name specified by DMA client
+ * @irq_handler: client callback for end of transfer
+ * @err_handler: client callback for error condition
+ * @data: clients context data for callbacks
+ * @dma_mode: direction of the transfer %DMA_MODE_READ or %DMA_MODE_WRITE
+ * @sg: pointer to the actual read/written chunk for scatter-gather emulation
+ * @sgbc: counter of processed bytes in the actual read/written chunk
+ * @resbytes: total residual number of bytes to transfer
+ *            (it can be lower or same as sum of SG mapped chunk sizes)
+ * @sgcount: number of chunks to be read/written
+ *
+ * Structure is used for IMX DMA processing. It would be probably good
+ * @struct dma_struct in the future for external interfacing and use
+ * @struct imx_dma_channel only as extension to it.
+ */
+
+struct imx_dma_channel {
+	const char *name;
+	void (*irq_handler) (int, void *, struct pt_regs *);
+	void (*err_handler) (int, void *, struct pt_regs *);
+	void *data;
+	dmamode_t  dma_mode;
+	struct scatterlist *sg;
+	unsigned int sgbc;
+	unsigned int sgcount;
+	unsigned int resbytes;
+	int dma_num;
+};
+
+extern struct imx_dma_channel imx_dma_channels[IMX_DMA_CHANNELS];
+
+
+/* The type to distinguish channel numbers parameter from ordinal int type */
+typedef int imx_dmach_t;
+
+int
+imx_dma_setup_single(imx_dmach_t dma_ch, dma_addr_t dma_address,
+		unsigned int dma_length, unsigned int dev_addr, dmamode_t dmamode);
+
+int
+imx_dma_setup_sg(imx_dmach_t dma_ch,
+		 struct scatterlist *sg, unsigned int sgcount, unsigned int dma_length,
+		 unsigned int dev_addr, dmamode_t dmamode);
+
+int
+imx_dma_setup_handlers(imx_dmach_t dma_ch,
+		void (*irq_handler) (int, void *, struct pt_regs *),
+		void (*err_handler) (int, void *, struct pt_regs *), void *data);
+
+void imx_dma_enable(imx_dmach_t dma_ch);
+
+void imx_dma_disable(imx_dmach_t dma_ch);
+
+int imx_dma_request(imx_dmach_t dma_ch, const char *name);
+
+void imx_dma_free(imx_dmach_t dma_ch);
+
+int imx_dma_request_by_prio(imx_dmach_t *pdma_ch, const char *name, imx_dma_prio prio);
+
+
+#endif	/* _ASM_ARCH_IMX_DMA_H */