path: root/drivers/net/irda/sa1100_ir.c

/*
 *  linux/drivers/net/irda/sa1100_ir.c
 *
 *  Copyright (C) 2000-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Infra-red driver for the StrongARM SA1100 embedded microprocessor
 *
 *  Note that we don't have to worry about the SA1111's DMA bugs in here,
 *  so we use the straight forward dma_map_* functions with a null pointer.
 *
 *  This driver takes one kernel command line parameter, sa1100ir=, with
 *  the following options:
 *	max_rate:baudrate	- set the maximum baud rate
 *	power_level:level	- set the transmitter power level
 *	tx_lpm:0|1		- set transmit low power mode
 */
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include <net/irda/irda_device.h>

#include <mach/dma.h>
#include <mach/hardware.h>
#include <asm/mach/irda.h>

static int power_level = 3;
static int tx_lpm;
static int max_rate = 4000000;

struct sa1100_buf {
	struct sk_buff		*skb;
	dma_addr_t		dma;
	dma_regs_t		*regs;
};

struct sa1100_irda {
	unsigned char		hscr0;
	unsigned char		utcr4;
	unsigned char		power;
	unsigned char		open;

	int			speed;
	int			newspeed;

	struct sa1100_buf	dma_rx;
	struct sa1100_buf	dma_tx;

	struct device		*dev;
	struct irda_platform_data *pdata;
	struct irlap_cb		*irlap;
	struct qos_info		qos;

	iobuff_t		tx_buff;
	iobuff_t		rx_buff;

	int (*tx_start)(struct sk_buff *, struct net_device *, struct sa1100_irda *);
};

static int sa1100_irda_set_speed(struct sa1100_irda *, int);

#define IS_FIR(si)		((si)->speed >= 4000000)

#define HPSIR_MAX_RXLEN		2047

/*
 * Allocate and map the receive buffer, unless it is already allocated.
 */
static int sa1100_irda_rx_alloc(struct sa1100_irda *si)
{
	if (si->dma_rx.skb)
		return 0;

	si->dma_rx.skb = alloc_skb(HPSIR_MAX_RXLEN + 1, GFP_ATOMIC);
	if (!si->dma_rx.skb) {
		printk(KERN_ERR "sa1100_ir: out of memory for RX SKB\n");
		return -ENOMEM;
	}

	/*
	 * Align any IP headers that may be contained
	 * within the frame.
	 */
	skb_reserve(si->dma_rx.skb, 1);

	si->dma_rx.dma = dma_map_single(si->dev, si->dma_rx.skb->data,
					HPSIR_MAX_RXLEN,
					DMA_FROM_DEVICE);
	if (dma_mapping_error(si->dev, si->dma_rx.dma)) {
		dev_kfree_skb_any(si->dma_rx.skb);
		return -ENOMEM;
	}

	return 0;
}

/*
 * We want to get here as soon as possible, and get the receiver setup.
 * We use the existing buffer.
 */
static void sa1100_irda_rx_dma_start(struct sa1100_irda *si)
{
	if (!si->dma_rx.skb) {
		printk(KERN_ERR "sa1100_ir: rx buffer went missing\n");
		return;
	}

	/*
	 * First empty receive FIFO
	 */
	Ser2HSCR0 = si->hscr0 | HSCR0_HSSP;

	/*
	 * Enable the DMA, receiver and receive interrupt.
	 */
	sa1100_clear_dma(si->dma_rx.regs);
	sa1100_start_dma(si->dma_rx.regs, si->dma_rx.dma, HPSIR_MAX_RXLEN);
	Ser2HSCR0 = si->hscr0 | HSCR0_HSSP | HSCR0_RXE;
}

static void sa1100_irda_check_speed(struct sa1100_irda *si)
{
	if (si->newspeed) {
		sa1100_irda_set_speed(si, si->newspeed);
		si->newspeed = 0;
	}
}

/*
 * HP-SIR format support.
 */
static int sa1100_irda_sir_tx_start(struct sk_buff *skb, struct net_device *dev,
	struct sa1100_irda *si)
{
	si->tx_buff.data = si->tx_buff.head;
	si->tx_buff.len  = async_wrap_skb(skb, si->tx_buff.data,
					  si->tx_buff.truesize);

	/*
	 * Set the transmit interrupt enable.  This will fire off an
	 * interrupt immediately.  Note that we disable the receiver
	 * so we won't get spurious characters received.
	 */
	Ser2UTCR3 = UTCR3_TIE