sa1100_ir.c

《linux驱动程序设计从入门到精通》一书中所有的程序代码含驱动和相应的应用程序

/*
 *  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_leve: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 <asm/irq.h>
#include <asm/dma.h>
#include <asm/hardware.h>
#include <asm/mach/irda.h>

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

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

	int			speed;
	int			newspeed;

	struct sk_buff		*txskb;
	struct sk_buff		*rxskb;
	dma_addr_t		txbuf_dma;
	dma_addr_t		rxbuf_dma;
	dma_regs_t		*txdma;
	dma_regs_t		*rxdma;

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

	iobuff_t		tx_buff;
	iobuff_t		rx_buff;
};

#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->rxskb)
		return 0;

	si->rxskb = alloc_skb(HPSIR_MAX_RXLEN + 1, GFP_ATOMIC);

	if (!si->rxskb) {
		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->rxskb, 1);

	si->rxbuf_dma = dma_map_single(si->dev, si->rxskb->data,
					HPSIR_MAX_RXLEN,
					DMA_FROM_DEVICE);
	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->rxskb) {
		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->rxdma);
	sa1100_start_dma(si->rxdma, si->rxbuf_dma, HPSIR_MAX_RXLEN);
	Ser2HSCR0 = si->hscr0 | HSCR0_HSSP | HSCR0_RXE;
}

/*
 * Set the IrDA communications speed.
 */
static int sa1100_irda_set_speed(struct sa1100_irda *si, int speed)
{
	unsigned long flags;
	int brd, ret = -EINVAL;

	switch (speed) {
	case 9600:	case 19200:	case 38400:
	case 57600:	case 115200:
		brd = 3686400 / (16 * speed) - 1;

		/*
		 * Stop the receive DMA.
		 */
		if (IS_FIR(si))
			sa1100_stop_dma(si->rxdma);

		local_irq_save(flags);

		Ser2UTCR3 = 0;
		Ser2HSCR0 = HSCR0_UART;

		Ser2UTCR1 = brd >> 8;
		Ser2UTCR2 = brd;

		/*
		 * Clear status register
		 */
		Ser2UTSR0 = UTSR0_REB | UTSR0_RBB | UTSR0_RID;
		Ser2UTCR3 = UTCR3_RIE | UTCR3_RXE | UTCR3_TXE;

		if (si->pdata->set_speed)
			si->pdata->set_speed(si->dev, speed);

		si->speed = speed;

		local_irq_restore(flags);
		ret = 0;
		break;

	case 4000000:
		local_irq_save(flags);

		si->hscr0 = 0;

		Ser2HSSR0 = 0xff;
		Ser2HSCR0 = si->hscr0 | HSCR0_HSSP;
		Ser2UTCR3 = 0;

		si->speed = speed;

		if (si->pdata->set_speed)
			si->pdata->set_speed(si->dev, speed);

		sa1100_irda_rx_alloc(si);
		sa1100_irda_rx_dma_start(si);

		local_irq_restore(flags);

		break;

	default:
		break;
	}

	return ret;
}

/*
 * Control the power state of the IrDA transmitter.
 * State:
 *  0 - off
 *  1 - short range, lowest power
 *  2 - medium range, medium power
 *  3 - maximum range, high power
 *
 * Currently, only assabet is known to support this.
 */
static int
__sa1100_irda_set_power(struct sa1100_irda *si, unsigned int state)
{
	int ret = 0;
	if (si->pdata->set_power)
		ret = si->pdata->set_power(si->dev, state);
	return ret;
}

static inline int
sa1100_set_power(struct sa1100_irda *si, unsigned int state)
{
	int ret;

	ret = __sa1100_irda_set_power(si, state);
	if (ret == 0)
		si->power = state;

	return ret;
}

static int sa1100_irda_startup(struct sa1100_irda *si)
{
	int ret;

	/*
	 * Ensure that the ports for this device are setup correctly.
	 */
	if (si->pdata->startup)
		si->pdata->startup(si->dev);

	/*
	 * Configure PPC for IRDA - we want to drive TXD2 low.
	 * We also want to drive this pin low during sleep.
	 */
	PPSR &= ~PPC_TXD2;
	PSDR &= ~PPC_TXD2;
	PPDR |= PPC_TXD2;

	/*
	 * Enable HP-SIR modulation, and ensure that the port is disabled.
	 */
	Ser2UTCR3 = 0;
	Ser2HSCR0 = HSCR0_UART;
	Ser2UTCR4 = si->utcr4;
	Ser2UTCR0 = UTCR0_8BitData;
	Ser2HSCR2 = HSCR2_TrDataH | HSCR2_RcDataL;

	/*
	 * Clear status register
	 */
	Ser2UTSR0 = UTSR0_REB | UTSR0_RBB | UTSR0_RID;

	ret = sa1100_irda_set_speed(si, si->speed = 9600);
	if (ret) {
		Ser2UTCR3 = 0;
		Ser2HSCR0 = 0;

		if (si->pdata->shutdown)
			si->pdata->shutdown(si->dev);
	}

	return ret;
}

static void sa1100_irda_shutdown(struct sa1100_irda *si)
{
	/*
	 * Stop all DMA activity.
	 */
	sa1100_stop_dma(si->rxdma);
	sa1100_stop_dma(si->txdma);

	/* Disable the port. */
	Ser2UTCR3 = 0;
	Ser2HSCR0 = 0;

	if (si->pdata->shutdown)
		si->pdata->shutdown(si->dev);
}

#ifdef CONFIG_PM
/*
 * Suspend the IrDA interface.
 */
static int sa1100_irda_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	struct sa1100_irda *si;

	if (!dev)
		return 0;

	si = dev->priv;
	if (si->open) {
		/*
		 * Stop the transmit queue
		 */
		netif_device_detach(dev);
		disable_irq(dev->irq);
		sa1100_irda_shutdown(si);
		__sa1100_irda_set_power(si, 0);
	}

	return 0;
}

/*
 * Resume the IrDA interface.
 */
static int sa1100_irda_resume(struct platform_device *pdev)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	struct sa1100_irda *si;

	if (!dev)
		return 0;

	si = dev->priv;
	if (si->open) {
		/*
		 * If we missed a speed change, initialise at the new speed
		 * directly.  It is debatable whether this is actually
		 * required, but in the interests of continuing from where
		 * we left off it is desireable.  The converse argument is
		 * that we should re-negotiate at 9600 baud again.
		 */
		if (si->newspeed) {
			si->speed = si->newspeed;
			si->newspeed = 0;
		}

		sa1100_irda_startup(si);
		__sa1100_irda_set_power(si, si->power);
		enable_irq(dev->irq);

		/*
		 * This automatically wakes up the queue
		 */
		netif_device_attach(dev);
	}

	return 0;
}
#else
#define sa1100_irda_suspend	NULL
#define sa1100_irda_resume	NULL
#endif

/*
 * HP-SIR format interrupt service routines.
 */
static void sa1100_irda_hpsir_irq(struct net_device *dev)
{
	struct sa1100_irda *si = dev->priv;
	int status;

	status = Ser2UTSR0;

	/*
	 * Deal with any receive errors first.  The bytes in error may be
	 * the only bytes in the receive FIFO, so we do this first.
	 */
	while (status & UTSR0_EIF) {
		int stat, data;

		stat = Ser2UTSR1;
		data = Ser2UTDR;

		if (stat & (UTSR1_FRE | UTSR1_ROR)) {
			si->stats.rx_errors++;
			if (stat & UTSR1_FRE)
				si->stats.rx_frame_errors++;
			if (stat & UTSR1_ROR)
				si->stats.rx_fifo_errors++;
		} else
			async_unwrap_char(dev, &si->stats, &si->rx_buff, data);

		status = Ser2UTSR0;
	}

	/*
	 * We must clear certain bits.
	 */
	Ser2UTSR0 = status & (UTSR0_RID | UTSR0_RBB | UTSR0_REB);

	if (status & UTSR0_RFS) {
		/*
		 * There are at least 4 bytes in the FIFO.  Read 3 bytes
		 * and leave the rest to the block below.
		 */
		async_unwrap_char(dev, &si->stats, &si->rx_buff, Ser2UTDR);
		async_unwrap_char(dev, &si->stats, &si->rx_buff, Ser2UTDR);
		async_unwrap_char(dev, &si->stats, &si->rx_buff, Ser2UTDR);
	}

	if (status & (UTSR0_RFS | UTSR0_RID)) {
		/*
		 * Fifo contains more than 1 character.
		 */
		do {
			async_unwrap_char(dev, &si->stats, &si->rx_buff,
					  Ser2UTDR);
		} while (Ser2UTSR1 & UTSR1_RNE);

		dev->last_rx = jiffies;
	}

	if (status & UTSR0_TFS && si->tx_buff.len) {
		/*
		 * Transmitter FIFO is not full
		 */
		do {
			Ser2UTDR = *si->tx_buff.data++;
			si->tx_buff.len -= 1;
		} while (Ser2UTSR1 & UTSR1_TNF && si->tx_buff.len);

		if (si->tx_buff.len == 0) {
			si->stats.tx_packets++;
			si->stats.tx_bytes += si->tx_buff.data -
					      si->tx_buff.head;

			/*
			 * We need to ensure that the transmitter has
			 * finished.
			 */
			do
				rmb();
			while (Ser2UTSR1 & UTSR1_TBY);

			/*
			 * Ok, we've finished transmitting.  Now enable
			 * the receiver.  Sometimes we get a receive IRQ
			 * immediately after a transmit...
			 */
			Ser2UTSR0 = UTSR0_REB | UTSR0_RBB | UTSR0_RID;
			Ser2UTCR3 = UTCR3_RIE | UTCR3_RXE | UTCR3_TXE;

			if (si->newspeed) {
				sa1100_irda_set_speed(si, si->newspeed);
				si->newspeed = 0;
			}

			/* I'm hungry! */
			netif_wake_queue(dev);
		}
	}
}

static void sa1100_irda_fir_error(struct sa1100_irda *si, struct net_device *dev)
{
	struct sk_buff *skb = si->rxskb;
	dma_addr_t dma_addr;
	unsigned int len, stat, data;

	if (!skb) {
		printk(KERN_ERR "sa1100_ir: SKB is NULL!\n");
		return;
	}

	/*
	 * Get the current data position.
	 */
	dma_addr = sa1100_get_dma_pos(si->rxdma);
	len = dma_addr - si->rxbuf_dma;
	if (len > HPSIR_MAX_RXLEN)
		len = HPSIR_MAX_RXLEN;
	dma_unmap_single(si->dev, si->rxbuf_dma, len, DMA_FROM_DEVICE);

	do {
		/*
		 * Read Status, and then Data.
		 */
		stat = Ser2HSSR1;
		rmb();
		data = Ser2HSDR;

		if (stat & (HSSR1_CRE | HSSR1_ROR)) {
			si->stats.rx_errors++;
			if (stat & HSSR1_CRE)
				si->stats.rx_crc_errors++;
			if (stat & HSSR1_ROR)
				si->stats.rx_frame_errors++;
		} else
			skb->data[len++] = data;

		/*
		 * If we hit the end of frame, there's
		 * no point in continuing.
		 */
		if (stat & HSSR1_EOF)
			break;
	} while (Ser2HSSR0 & HSSR0_EIF);

	if (stat & HSSR1_EOF) {
		si->rxskb = NULL;

		skb_put(skb, len);
		skb->dev = dev;
		skb->mac.raw = skb->data;
		skb->protocol = htons(ETH_P_IRDA);
		si->stats.rx_packets++;
		si->stats.rx_bytes += len;

		/*
		 * Before we pass the buffer up, allocate a new one.
		 */
		sa1100_irda_rx_alloc(si);

		netif_rx(skb);
		dev->last_rx = jiffies;
	} else {
		/*
		 * Remap the buffer.
		 */