path: root/drivers/spi/pxa2xx_spi.c

/*
 * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/delay.h>
#include <asm/dma.h>

#include <asm/arch/hardware.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/regs-ssp.h>
#include <asm/arch/ssp.h>
#include <asm/arch/pxa2xx_spi.h>

MODULE_AUTHOR("Stephen Street");
MODULE_DESCRIPTION("PXA2xx SSP SPI Controller");
MODULE_LICENSE("GPL");

#define MAX_BUSES 3

#define DMA_INT_MASK (DCSR_ENDINTR | DCSR_STARTINTR | DCSR_BUSERR)
#define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK)
#define IS_DMA_ALIGNED(x) (((u32)(x)&0x07)==0)

/* for testing SSCR1 changes that require SSP restart, basically
 * everything except the service and interrupt enables */
#define SSCR1_CHANGE_MASK (SSCR1_TTELP | SSCR1_TTE | SSCR1_EBCEI | SSCR1_SCFR \
				| SSCR1_ECRA | SSCR1_ECRB | SSCR1_SCLKDIR \
				| SSCR1_RWOT | SSCR1_TRAIL | SSCR1_PINTE \
				| SSCR1_STRF | SSCR1_EFWR |SSCR1_RFT \
				| SSCR1_TFT | SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define DEFINE_SSP_REG(reg, off) \
static inline u32 read_##reg(void *p) { return __raw_readl(p + (off)); } \
static inline void write_##reg(u32 v, void *p) { __raw_writel(v, p + (off)); }

DEFINE_SSP_REG(SSCR0, 0x00)
DEFINE_SSP_REG(SSCR1, 0x04)
DEFINE_SSP_REG(SSSR, 0x08)
DEFINE_SSP_REG(SSITR, 0x0c)
DEFINE_SSP_REG(SSDR, 0x10)
DEFINE_SSP_REG(SSTO, 0x28)
DEFINE_SSP_REG(SSPSP, 0x2c)

#define START_STATE ((void*)0)
#define RUNNING_STATE ((void*)1)
#define DONE_STATE ((void*)2)
#define ERROR_STATE ((void*)-1)

#define QUEUE_RUNNING 0
#define QUEUE_STOPPED 1

struct driver_data {
	/* Driver model hookup */
	struct platform_device *pdev;

	/* SSP Info */
	struct ssp_device *ssp;

	/* SPI framework hookup */
	enum pxa_ssp_type ssp_type;
	struct spi_master *master;

	/* PXA hookup */
	struct pxa2xx_spi_master *master_info;

	/* DMA setup stuff */
	int rx_channel;
	int tx_channel;
	u32 *null_dma_buf;

	/* SSP register addresses */
	void *ioaddr;
	u32 ssdr_physical;

	/* SSP masks*/
	u32 dma_cr1;
	u32 int_cr1;
	u32 clear_sr;
	u32 mask_sr;

	/* Driver message queue */
	struct workqueue_struct	*workqueue;
	struct work_struct pump_messages;
	spinlock_t lock;
	struct list_head queue;
	int busy;
	int run;

	/* Message Transfer pump */
	struct tasklet_struct pump_transfers;

	/* Current message transfer state info */
	struct spi_message* cur_msg;
	struct spi_transfer* cur_transfer;
	struct chip_data *cur_chip;
	size_t len;
	void *tx;
	void *tx_end;
	void *rx;
	void *rx_end;
	int dma_mapped;
	dma_addr_t rx_dma;
	dma_addr_t tx_dma;
	size_t rx_map_len;
	size_t tx_map_len;
	u8 n_bytes;
	u32 dma_width;
	int cs_change;
	int (*write)(struct driver_data *drv_data);
	int (*read)(struct driver_data *drv_data);
	irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
	void (*cs_control)(u32 command);
};

struct chip_data {
	u32 cr0;
	u32 cr1;
	u32 psp;
	u32 timeout;
	u8 n_bytes;
	u32 dma_width;
	u32 dma_burst_size;
	u32 threshold;
	u32 dma_threshold;
	u8 enable_dma;
	u8 bits_per_word;
	u32 speed_hz;
	int (*write)(struct driver_data *drv_data);
	int (*read)(struct driver_data *drv_data);
	void (*cs_control)(u32 command);
};

static void pump_messages(struct work_struct *work);

static int flush(struct driver_data *drv_data)
{
	unsigned long limit = loops_per_jiffy << 1;

	void *reg = drv_data->ioaddr;

	do {
		while (read_SSSR(reg) & SSSR_RNE) {
			read_SSDR(reg);
		}
	} while ((read_SSSR(reg) & SSSR_BSY) && limit--);
	write_SSSR(SSSR_ROR, reg);

	return limit;
}

static void null_cs_control(u32 command)
{
}

static int null_writer(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;
	u8 n_bytes = drv_data->n_bytes;

	if (((read_SSSR(reg) & 0x00000f00) == 0x00000f00)
		|| (drv_data->tx == drv_data->tx_end))
		return 0;

	write_SSDR(0, reg);
	drv_data->tx += n_bytes;

	return 1;
}

static int null_reader(struct driver_data *drv_data)
{
	void *reg = drv_data->ioaddr;
	u8 n_bytes = drv_data->n_bytes;

	while ((read_SSSR(reg) & SSSR_RNE)
		&& (drv_data->rx < drv_data->rx_end)) {
		read_SSDR(reg);
		drv_data->rx += n_bytes;
	}

	return drv_data->rx == drv_data->rx_end;
}

static int u8_wr