path: root/drivers/dma/s3c24xx-dma.c

/*
 * S3C24XX DMA handling
 *
 * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
 *
 * based on amba-pl08x.c
 *
 * Copyright (c) 2006 ARM Ltd.
 * Copyright (c) 2010 ST-Ericsson SA
 *
 * Author: Peter Pearse <peter.pearse@arm.com>
 * Author: Linus Walleij <linus.walleij@stericsson.com>
 *
 * 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.
 *
 * The DMA controllers in S3C24XX SoCs have a varying number of DMA signals
 * that can be routed to any of the 4 to 8 hardware-channels.
 *
 * Therefore on these DMA controllers the number of channels
 * and the number of incoming DMA signals are two totally different things.
 * It is usually not possible to theoretically handle all physical signals,
 * so a multiplexing scheme with possible denial of use is necessary.
 *
 * Open items:
 * - bursts
 */

#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_data/dma-s3c24xx.h>

#include "dmaengine.h"
#include "virt-dma.h"

#define MAX_DMA_CHANNELS	8

#define S3C24XX_DISRC			0x00
#define S3C24XX_DISRCC			0x04
#define S3C24XX_DISRCC_INC_INCREMENT	0
#define S3C24XX_DISRCC_INC_FIXED	BIT(0)
#define S3C24XX_DISRCC_LOC_AHB		0
#define S3C24XX_DISRCC_LOC_APB		BIT(1)

#define S3C24XX_DIDST			0x08
#define S3C24XX_DIDSTC			0x0c
#define S3C24XX_DIDSTC_INC_INCREMENT	0
#define S3C24XX_DIDSTC_INC_FIXED	BIT(0)
#define S3C24XX_DIDSTC_LOC_AHB		0
#define S3C24XX_DIDSTC_LOC_APB		BIT(1)
#define S3C24XX_DIDSTC_INT_TC0		0
#define S3C24XX_DIDSTC_INT_RELOAD	BIT(2)

#define S3C24XX_DCON			0x10

#define S3C24XX_DCON_TC_MASK		0xfffff
#define S3C24XX_DCON_DSZ_BYTE		(0 << 20)
#define S3C24XX_DCON_DSZ_HALFWORD	(1 << 20)
#define S3C24XX_DCON_DSZ_WORD		(2 << 20)
#define S3C24XX_DCON_DSZ_MASK		(3 << 20)
#define S3C24XX_DCON_DSZ_SHIFT		20
#define S3C24XX_DCON_AUTORELOAD		0
#define S3C24XX_DCON_NORELOAD		BIT(22)
#define S3C24XX_DCON_HWTRIG		BIT(23)
#define S3C24XX_DCON_HWSRC_SHIFT	24
#define S3C24XX_DCON_SERV_SINGLE	0
#define S3C24XX_DCON_SERV_WHOLE		BIT(27)
#define S3C24XX_DCON_TSZ_UNIT		0
#define S3C24XX_DCON_TSZ_BURST4		BIT(28)
#define S3C24XX_DCON_INT		BIT(29)
#define S3C24XX_DCON_SYNC_PCLK		0
#define S3C24XX_DCON_SYNC_HCLK		BIT(30)
#define S3C24XX_DCON_DEMAND		0
#define S3C24XX_DCON_HANDSHAKE		BIT(31)

#define S3C24XX_DSTAT			0x14
#define S3C24XX_DSTAT_STAT_BUSY		BIT(20)
#define S3C24XX_DSTAT_CURRTC_MASK	0xfffff

#define S3C24XX_DMASKTRIG		0x20
#define S3C24XX_DMASKTRIG_SWTRIG	BIT(0)
#define S3C24XX_DMASKTRIG_ON		BIT(1)
#define S3C24XX_DMASKTRIG_STOP		BIT(2)

#define S3C24XX_DMAREQSEL		0x24
#define S3C24XX_DMAREQSEL_HW		BIT(0)

/*
 * S3C2410, S3C2440 and S3C2442 SoCs cannot select any physical channel
 * for a DMA source. Instead only specific channels are valid.
 * All of these SoCs have 4 physical channels and the number of request
 * source bits is 3. Additionally we also need 1 bit to mark the channel
 * as valid.
 * Therefore we separate the chansel element of the channel data into 4
 * parts of 4 bits each, to hold the information if the channel is valid
 * and the hw request source to use.
 *
 * Example:
 * SDI is valid on channels 0, 2 and 3 - with varying hw request sources.
 * For it the chansel field would look like
 *
 * ((BIT(3) | 1) << 3 * 4) | // channel 3, with request source 1
 * ((BIT(3) | 2) << 2 * 4) | // channel 2, with request source 2
 * ((BIT(3) | 2) << 0 * 4)   // channel 0, with request source 2
 */
#define S3C24XX_CHANSEL_WIDTH		4
#define S3C24XX_CHANSEL_VALID		BIT(3)
#define S3C24XX_CHANSEL_REQ_MASK	7

/*
 * struct soc_data - vendor-specific config parameters for individual SoCs
 * @stride: spacing between the registers of each channel
 * @has_reqsel: does the controller use the newer requestselection mechanism
 * @has_clocks: are controllable dma-clocks present
 */
struct soc_data {
	int stride;
	bool has_reqsel;
	bool has_clocks;
};

/*
 * enum s3c24xx_dma_chan_state - holds the virtual