at91_mci.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

		else
			at91_mci_write(host, AT91_PDC_PTCR, AT91_PDC_TXTEN);
	}
	return ier;
}

/*
 * Wait for a command to complete
 */
static void at91mci_process_command(struct at91mci_host *host, struct mmc_command *cmd)
{
	unsigned int ier;

	ier = at91_mci_send_command(host, cmd);

	pr_debug("setting ier to %08X\n", ier);

	/* Stop on errors or the required value */
	at91_mci_write(host, AT91_MCI_IER, AT91_MCI_ERRORS | ier);
}

/*
 * Process the next step in the request
 */
static void at91mci_process_next(struct at91mci_host *host)
{
	if (!(host->flags & FL_SENT_COMMAND)) {
		host->flags |= FL_SENT_COMMAND;
		at91mci_process_command(host, host->request->cmd);
	}
	else if ((!(host->flags & FL_SENT_STOP)) && host->request->stop) {
		host->flags |= FL_SENT_STOP;
		at91mci_process_command(host, host->request->stop);
	}
	else
		mmc_request_done(host->mmc, host->request);
}

/*
 * Handle a command that has been completed
 */
static void at91mci_completed_command(struct at91mci_host *host)
{
	struct mmc_command *cmd = host->cmd;
	unsigned int status;

	at91_mci_write(host, AT91_MCI_IDR, 0xffffffff);

	cmd->resp[0] = at91_mci_read(host, AT91_MCI_RSPR(0));
	cmd->resp[1] = at91_mci_read(host, AT91_MCI_RSPR(1));
	cmd->resp[2] = at91_mci_read(host, AT91_MCI_RSPR(2));
	cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3));

	if (host->buffer) {
		dma_free_coherent(NULL, host->total_length, host->buffer, host->physical_address);
		host->buffer = NULL;
	}

	status = at91_mci_read(host, AT91_MCI_SR);

	pr_debug("Status = %08X [%08X %08X %08X %08X]\n",
		 status, cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3]);

	if (status & (AT91_MCI_RINDE | AT91_MCI_RDIRE | AT91_MCI_RCRCE |
			AT91_MCI_RENDE | AT91_MCI_RTOE | AT91_MCI_DCRCE |
			AT91_MCI_DTOE | AT91_MCI_OVRE | AT91_MCI_UNRE)) {
		if ((status & AT91_MCI_RCRCE) &&
			((cmd->opcode == MMC_SEND_OP_COND) || (cmd->opcode == SD_APP_OP_COND))) {
			cmd->error = MMC_ERR_NONE;
		}
		else {
			if (status & (AT91_MCI_RTOE | AT91_MCI_DTOE))
				cmd->error = MMC_ERR_TIMEOUT;
			else if (status & (AT91_MCI_RCRCE | AT91_MCI_DCRCE))
				cmd->error = MMC_ERR_BADCRC;
			else if (status & (AT91_MCI_OVRE | AT91_MCI_UNRE))
				cmd->error = MMC_ERR_FIFO;
			else
				cmd->error = MMC_ERR_FAILED;

			pr_debug("Error detected and set to %d (cmd = %d, retries = %d)\n",
				 cmd->error, cmd->opcode, cmd->retries);
		}
	}
	else
		cmd->error = MMC_ERR_NONE;

	at91mci_process_next(host);
}

/*
 * Handle an MMC request
 */
static void at91_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
	struct at91mci_host *host = mmc_priv(mmc);
	host->request = mrq;
	host->flags = 0;

	at91mci_process_next(host);
}

/*
 * Set the IOS
 */
static void at91_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
	int clkdiv;
	struct at91mci_host *host = mmc_priv(mmc);
	unsigned long at91_master_clock = clk_get_rate(host->mci_clk);

	host->bus_mode = ios->bus_mode;

	if (ios->clock == 0) {
		/* Disable the MCI controller */
		at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIDIS);
		clkdiv = 0;
	}
	else {
		/* Enable the MCI controller */
		at91_mci_write(host, AT91_MCI_CR, AT91_MCI_MCIEN);

		if ((at91_master_clock % (ios->clock * 2)) == 0)
			clkdiv = ((at91_master_clock / ios->clock) / 2) - 1;
		else
			clkdiv = (at91_master_clock / ios->clock) / 2;

		pr_debug("clkdiv = %d. mcck = %ld\n", clkdiv,
			at91_master_clock / (2 * (clkdiv + 1)));
	}
	if (ios->bus_width == MMC_BUS_WIDTH_4 && host->board->wire4) {
		pr_debug("MMC: Setting controller bus width to 4\n");
		at91_mci_write(host, AT91_MCI_SDCR, at91_mci_read(host, AT91_MCI_SDCR) | AT91_MCI_SDCBUS);
	}
	else {
		pr_debug("MMC: Setting controller bus width to 1\n");
		at91_mci_write(host, AT91_MCI_SDCR, at91_mci_read(host, AT91_MCI_SDCR) & ~AT91_MCI_SDCBUS);
	}

	/* Set the clock divider */
	at91_mci_write(host, AT91_MCI_MR, (at91_mci_read(host, AT91_MCI_MR) & ~AT91_MCI_CLKDIV) | clkdiv);

	/* maybe switch power to the card */
	if (host->board->vcc_pin) {
		switch (ios->power_mode) {
			case MMC_POWER_OFF:
				at91_set_gpio_value(host->board->vcc_pin, 0);
				break;
			case MMC_POWER_UP:
			case MMC_POWER_ON:
				at91_set_gpio_value(host->board->vcc_pin, 1);
				break;
		}
	}
}

/*
 * Handle an interrupt
 */
static irqreturn_t at91_mci_irq(int irq, void *devid)
{
	struct at91mci_host *host = devid;
	int completed = 0;
	unsigned int int_status, int_mask;

	int_status = at91_mci_read(host, AT91_MCI_SR);
	int_mask = at91_mci_read(host, AT91_MCI_IMR);
	
	pr_debug("MCI irq: status = %08X, %08X, %08X\n", int_status, int_mask,
		int_status & int_mask);
	
	int_status = int_status & int_mask;

	if (int_status & AT91_MCI_ERRORS) {
		completed = 1;
		
		if (int_status & AT91_MCI_UNRE)
			pr_debug("MMC: Underrun error\n");
		if (int_status & AT91_MCI_OVRE)
			pr_debug("MMC: Overrun error\n");
		if (int_status & AT91_MCI_DTOE)
			pr_debug("MMC: Data timeout\n");
		if (int_status & AT91_MCI_DCRCE)
			pr_debug("MMC: CRC error in data\n");
		if (int_status & AT91_MCI_RTOE)
			pr_debug("MMC: Response timeout\n");
		if (int_status & AT91_MCI_RENDE)
			pr_debug("MMC: Response end bit error\n");
		if (int_status & AT91_MCI_RCRCE)
			pr_debug("MMC: Response CRC error\n");
		if (int_status & AT91_MCI_RDIRE)
			pr_debug("MMC: Response direction error\n");
		if (int_status & AT91_MCI_RINDE)
			pr_debug("MMC: Response index error\n");
	} else {
		/* Only continue processing if no errors */

		if (int_status & AT91_MCI_TXBUFE) {
			pr_debug("TX buffer empty\n");
			at91_mci_handle_transmitted(host);
		}

		if (int_status & AT91_MCI_RXBUFF) {
			pr_debug("RX buffer full\n");
			at91_mci_write(host, AT91_MCI_IER, AT91_MCI_CMDRDY);
		}

		if (int_status & AT91_MCI_ENDTX)
			pr_debug("Transmit has ended\n");

		if (int_status & AT91_MCI_ENDRX) {
			pr_debug("Receive has ended\n");
			at91mci_post_dma_read(host);
		}

		if (int_status & AT91_MCI_NOTBUSY) {
			pr_debug("Card is ready\n");
			at91_mci_write(host, AT91_MCI_IER, AT91_MCI_CMDRDY);
		}

		if (int_status & AT91_MCI_DTIP)
			pr_debug("Data transfer in progress\n");

		if (int_status & AT91_MCI_BLKE)
			pr_debug("Block transfer has ended\n");

		if (int_status & AT91_MCI_TXRDY)
			pr_debug("Ready to transmit\n");

		if (int_status & AT91_MCI_RXRDY)
			pr_debug("Ready to receive\n");

		if (int_status & AT91_MCI_CMDRDY) {
			pr_debug("Command ready\n");
			completed = 1;
		}
	}

	if (completed) {
		pr_debug("Completed command\n");
		at91_mci_write(host, AT91_MCI_IDR, 0xffffffff);
		at91mci_completed_command(host);
	} else
		at91_mci_write(host, AT91_MCI_IDR, int_status);

	return IRQ_HANDLED;
}

static irqreturn_t at91_mmc_det_irq(int irq, void *_host)
{
	struct at91mci_host *host = _host;
	int present = !at91_get_gpio_value(irq);

	/*
	 * we expect this irq on both insert and remove,
	 * and use a short delay to debounce.
	 */
	if (present != host->present) {
		host->present = present;
		pr_debug("%s: card %s\n", mmc_hostname(host->mmc),
			present ? "insert" : "remove");
		if (!present) {
			pr_debug("****** Resetting SD-card bus width ******\n");
			at91_mci_write(host, AT91_MCI_SDCR, at91_mci_read(host, AT91_MCI_SDCR) & ~AT91_MCI_SDCBUS);
		}
		mmc_detect_change(host->mmc, msecs_to_jiffies(100));
	}
	return IRQ_HANDLED;
}

static int at91_mci_get_ro(struct mmc_host *mmc)
{
	int read_only = 0;
	struct at91mci_host *host = mmc_priv(mmc);

	if (host->board->wp_pin) {
		read_only = at91_get_gpio_value(host->board->wp_pin);
		printk(KERN_WARNING "%s: card is %s\n", mmc_hostname(mmc),
				(read_only ? "read-only" : "read-write") );
	}
	else {
		printk(KERN_WARNING "%s: host does not support reading read-only "
				"switch.  Assuming write-enable.\n", mmc_hostname(mmc));
	}
	return read_only;
}

static const struct mmc_host_ops at91_mci_ops = {
	.request	= at91_mci_request,
	.set_ios	= at91_mci_set_ios,
	.get_ro		= at91_mci_get_ro,
};

/*
 * Probe for the device
 */
static int __init at91_mci_probe(struct platform_device *pdev)
{
	struct mmc_host *mmc;
	struct at91mci_host *host;
	struct resource *res;
	int ret;

	pr_debug("Probe MCI devices\n");

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENXIO;

	if (!request_mem_region(res->start, res->end - res->start + 1, DRIVER_NAME))
		return -EBUSY;

	mmc = mmc_alloc_host(sizeof(struct at91mci_host), &pdev->dev);
	if (!mmc) {
		pr_debug("Failed to allocate mmc host\n");
		release_mem_region(res->start, res->end - res->start + 1);
		return -ENOMEM;
	}

	mmc->ops = &at91_mci_ops;
	mmc->f_min = 375000;
	mmc->f_max = 25000000;
	mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
	mmc->caps = MMC_CAP_BYTEBLOCK;

	host = mmc_priv(mmc);
	host->mmc = mmc;
	host->buffer = NULL;
	host->bus_mode = 0;
	host->board = pdev->dev.platform_data;
	if (host->board->wire4) {
#ifdef SUPPORT_4WIRE
		mmc->caps |= MMC_CAP_4_BIT_DATA;
#else
		printk("AT91 MMC: 4 wire bus mode not supported by this driver - using 1 wire\n");
#endif
	}

	/*
	 * Get Clock
	 */
	host->mci_clk = clk_get(&pdev->dev, "mci_clk");
	if (IS_ERR(host->mci_clk)) {
		printk(KERN_ERR "AT91 MMC: no clock defined.\n");
		mmc_free_host(mmc);
		release_mem_region(res->start, res->end - res->start + 1);
		return -ENODEV;
	}

	/*
	 * Map I/O region
	 */
	host->baseaddr = ioremap(res->start, res->end - res->start + 1);
	if (!host->baseaddr) {
		clk_put(host->mci_clk);
		mmc_free_host(mmc);
		release_mem_region(res->start, res->end - res->start + 1);
		return -ENOMEM;
	}

	/*
	 * Reset hardware
	 */
	clk_enable(host->mci_clk);		/* Enable the peripheral clock */
	at91_mci_disable(host);
	at91_mci_enable(host);

	/*
	 * Allocate the MCI interrupt
	 */
	host->irq = platform_get_irq(pdev, 0);
	ret = request_irq(host->irq, at91_mci_irq, IRQF_SHARED, DRIVER_NAME, host);
	if (ret) {
		printk(KERN_ERR "AT91 MMC: Failed to request MCI interrupt\n");
		clk_disable(host->mci_clk);
		clk_put(host->mci_clk);
		mmc_free_host(mmc);
		iounmap(host->baseaddr);
		release_mem_region(res->start, res->end - res->start + 1);
		return ret;
	}

	platform_set_drvdata(pdev, mmc);

	/*
	 * Add host to MMC layer
	 */
	if (host->board->det_pin)
		host->present = !at91_get_gpio_value(host->board->det_pin);
	else
		host->present = -1;

	mmc_add_host(mmc);

	/*
	 * monitor card insertion/removal if we can
	 */
	if (host->board->det_pin) {
		ret = request_irq(host->board->det_pin, at91_mmc_det_irq,
				0, DRIVER_NAME, host);
		if (ret)
			printk(KERN_ERR "AT91 MMC: Couldn't allocate MMC detect irq\n");
	}

	pr_debug("Added MCI driver\n");

	return 0;
}

/*
 * Remove a device
 */
static int __exit at91_mci_remove(struct platform_device *pdev)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	struct at91mci_host *host;
	struct resource *res;

	if (!mmc)
		return -1;

	host = mmc_priv(mmc);

	if (host->present != -1) {
		free_irq(host->board->det_pin, host);
		cancel_delayed_work(&host->mmc->detect);
	}

	at91_mci_disable(host);
	mmc_remove_host(mmc);
	free_irq(host->irq, host);

	clk_disable(host->mci_clk);			/* Disable the peripheral clock */
	clk_put(host->mci_clk);

	iounmap(host->baseaddr);
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, res->end - res->start + 1);

	mmc_free_host(mmc);
	platform_set_drvdata(pdev, NULL);
	pr_debug("MCI Removed\n");

	return 0;
}

#ifdef CONFIG_PM
static int at91_mci_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	int ret = 0;

	if (mmc)
		ret = mmc_suspend_host(mmc, state);

	return ret;
}

static int at91_mci_resume(struct platform_device *pdev)
{
	struct mmc_host *mmc = platform_get_drvdata(pdev);
	int ret = 0;

	if (mmc)
		ret = mmc_resume_host(mmc);

	return ret;
}
#else
#define at91_mci_suspend	NULL
#define at91_mci_resume		NULL
#endif

static struct platform_driver at91_mci_driver = {
	.remove		= __exit_p(at91_mci_remove),
	.suspend	= at91_mci_suspend,
	.resume		= at91_mci_resume,
	.driver		= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init at91_mci_init(void)
{
	return platform_driver_probe(&at91_mci_driver, at91_mci_probe);
}

static void __exit at91_mci_exit(void)
{
	platform_driver_unregister(&at91_mci_driver);
}

module_init(at91_mci_init);
module_exit(at91_mci_exit);

MODULE_DESCRIPTION("AT91 Multimedia Card Interface driver");
MODULE_AUTHOR("Nick Randell");
MODULE_LICENSE("GPL");