mmc.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

	kfree(ext_csd);

	mmc_deselect_cards(host);
}

static void mmc_read_scrs(struct mmc_host *host)
{
	int err;
	struct mmc_card *card;
	struct mmc_request mrq;
	struct mmc_command cmd;
	struct mmc_data data;
	struct scatterlist sg;

	list_for_each_entry(card, &host->cards, node) {
		if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
			continue;
		if (!mmc_card_sd(card))
			continue;

		err = mmc_select_card(host, card);
		if (err != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		memset(&cmd, 0, sizeof(struct mmc_command));

		cmd.opcode = MMC_APP_CMD;
		cmd.arg = card->rca << 16;
		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;

		err = mmc_wait_for_cmd(host, &cmd, 0);
		if ((err != MMC_ERR_NONE) || !(cmd.resp[0] & R1_APP_CMD)) {
			mmc_card_set_dead(card);
			continue;
		}

		memset(&cmd, 0, sizeof(struct mmc_command));

		cmd.opcode = SD_APP_SEND_SCR;
		cmd.arg = 0;
		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

		memset(&data, 0, sizeof(struct mmc_data));

		mmc_set_data_timeout(&data, card, 0);

		data.blksz = 1 << 3;
		data.blocks = 1;
		data.flags = MMC_DATA_READ;
		data.sg = &sg;
		data.sg_len = 1;

		memset(&mrq, 0, sizeof(struct mmc_request));

		mrq.cmd = &cmd;
		mrq.data = &data;

		sg_init_one(&sg, (u8*)card->raw_scr, 8);

		mmc_wait_for_req(host, &mrq);

		if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		card->raw_scr[0] = ntohl(card->raw_scr[0]);
		card->raw_scr[1] = ntohl(card->raw_scr[1]);

		mmc_decode_scr(card);
	}

	mmc_deselect_cards(host);
}

static void mmc_read_switch_caps(struct mmc_host *host)
{
	int err;
	struct mmc_card *card;
	struct mmc_request mrq;
	struct mmc_command cmd;
	struct mmc_data data;
	unsigned char *status;
	struct scatterlist sg;

	status = kmalloc(64, GFP_KERNEL);
	if (!status) {
		printk(KERN_WARNING "%s: Unable to allocate buffer for "
			"reading switch capabilities.\n",
			mmc_hostname(host));
		return;
	}

	list_for_each_entry(card, &host->cards, node) {
		if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
			continue;
		if (!mmc_card_sd(card))
			continue;
		if (card->scr.sda_vsn < SCR_SPEC_VER_1)
			continue;

		err = mmc_select_card(host, card);
		if (err != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		memset(&cmd, 0, sizeof(struct mmc_command));

		cmd.opcode = SD_SWITCH;
		cmd.arg = 0x00FFFFF1;
		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

		memset(&data, 0, sizeof(struct mmc_data));

		mmc_set_data_timeout(&data, card, 0);

		data.blksz = 64;
		data.blocks = 1;
		data.flags = MMC_DATA_READ;
		data.sg = &sg;
		data.sg_len = 1;

		memset(&mrq, 0, sizeof(struct mmc_request));

		mrq.cmd = &cmd;
		mrq.data = &data;

		sg_init_one(&sg, status, 64);

		mmc_wait_for_req(host, &mrq);

		if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		if (status[13] & 0x02)
			card->sw_caps.hs_max_dtr = 50000000;

		memset(&cmd, 0, sizeof(struct mmc_command));

		cmd.opcode = SD_SWITCH;
		cmd.arg = 0x80FFFFF1;
		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

		memset(&data, 0, sizeof(struct mmc_data));

		mmc_set_data_timeout(&data, card, 0);

		data.blksz = 64;
		data.blocks = 1;
		data.flags = MMC_DATA_READ;
		data.sg = &sg;
		data.sg_len = 1;

		memset(&mrq, 0, sizeof(struct mmc_request));

		mrq.cmd = &cmd;
		mrq.data = &data;

		sg_init_one(&sg, status, 64);

		mmc_wait_for_req(host, &mrq);

		if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
			mmc_card_set_dead(card);
			continue;
		}

		if ((status[16] & 0xF) != 1) {
			printk(KERN_WARNING "%s: Problem switching card "
				"into high-speed mode!\n",
				mmc_hostname(host));
			continue;
		}

		mmc_card_set_highspeed(card);
	}

	kfree(status);

	mmc_deselect_cards(host);
}

static unsigned int mmc_calculate_clock(struct mmc_host *host)
{
	struct mmc_card *card;
	unsigned int max_dtr = host->f_max;

	list_for_each_entry(card, &host->cards, node)
		if (!mmc_card_dead(card)) {
			if (mmc_card_highspeed(card) && mmc_card_sd(card)) {
				if (max_dtr > card->sw_caps.hs_max_dtr)
					max_dtr = card->sw_caps.hs_max_dtr;
			} else if (mmc_card_highspeed(card) && !mmc_card_sd(card)) {
				if (max_dtr > card->ext_csd.hs_max_dtr)
					max_dtr = card->ext_csd.hs_max_dtr;
			} else if (max_dtr > card->csd.max_dtr) {
				max_dtr = card->csd.max_dtr;
			}
		}

	pr_debug("%s: selected %d.%03dMHz transfer rate\n",
		 mmc_hostname(host),
		 max_dtr / 1000000, (max_dtr / 1000) % 1000);

	return max_dtr;
}

/*
 * Check whether cards we already know about are still present.
 * We do this by requesting status, and checking whether a card
 * responds.
 *
 * A request for status does not cause a state change in data
 * transfer mode.
 */
static void mmc_check_cards(struct mmc_host *host)
{
	struct list_head *l, *n;

	mmc_deselect_cards(host);

	list_for_each_safe(l, n, &host->cards) {
		struct mmc_card *card = mmc_list_to_card(l);
		struct mmc_command cmd;
		int err;

		cmd.opcode = MMC_SEND_STATUS;
		cmd.arg = card->rca << 16;
		cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;

		err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
		if (err == MMC_ERR_NONE)
			continue;

		mmc_card_set_dead(card);
	}
}

static void mmc_setup(struct mmc_host *host)
{
	if (host->ios.power_mode != MMC_POWER_ON) {
		int err;
		u32 ocr;

		host->mode = MMC_MODE_SD;

		mmc_power_up(host);
		mmc_idle_cards(host);

		err = mmc_send_app_op_cond(host, 0, &ocr);

		/*
		 * If we fail to detect any SD cards then try
		 * searching for MMC cards.
		 */
		if (err != MMC_ERR_NONE) {
			host->mode = MMC_MODE_MMC;

			err = mmc_send_op_cond(host, 0, &ocr);
			if (err != MMC_ERR_NONE)
				return;
		}

		host->ocr = mmc_select_voltage(host, ocr);

		/*
		 * Since we're changing the OCR value, we seem to
		 * need to tell some cards to go back to the idle
		 * state.  We wait 1ms to give cards time to
		 * respond.
		 */
		if (host->ocr)
			mmc_idle_cards(host);
	} else {
		host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
		host->ios.clock = host->f_min;
		mmc_set_ios(host);

		/*
		 * We should remember the OCR mask from the existing
		 * cards, and detect the new cards OCR mask, combine
		 * the two and re-select the VDD.  However, if we do
		 * change VDD, we should do an idle, and then do a
		 * full re-initialisation.  We would need to notify
		 * drivers so that they can re-setup the cards as
		 * well, while keeping their queues at bay.
		 *
		 * For the moment, we take the easy way out - if the
		 * new cards don't like our currently selected VDD,
		 * they drop off the bus.
		 */
	}

	if (host->ocr == 0)
		return;

	/*
	 * Send the selected OCR multiple times... until the cards
	 * all get the idea that they should be ready for CMD2.
	 * (My SanDisk card seems to need this.)
	 */
	if (host->mode == MMC_MODE_SD)
		mmc_send_app_op_cond(host, host->ocr, NULL);
	else
		mmc_send_op_cond(host, host->ocr, NULL);

	mmc_discover_cards(host);

	/*
	 * Ok, now switch to push-pull mode.
	 */
	host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
	mmc_set_ios(host);

	mmc_read_csds(host);

	if (host->mode == MMC_MODE_SD) {
		mmc_read_scrs(host);
		mmc_read_switch_caps(host);
	} else
		mmc_process_ext_csds(host);
}


/**
 *	mmc_detect_change - process change of state on a MMC socket
 *	@host: host which changed state.
 *	@delay: optional delay to wait before detection (jiffies)
 *
 *	All we know is that card(s) have been inserted or removed
 *	from the socket(s).  We don't know which socket or cards.
 */
void mmc_detect_change(struct mmc_host *host, unsigned long delay)
{
	mmc_schedule_delayed_work(&host->detect, delay);
}

EXPORT_SYMBOL(mmc_detect_change);


static void mmc_rescan(struct work_struct *work)
{
	struct mmc_host *host =
		container_of(work, struct mmc_host, detect.work);
	struct list_head *l, *n;
	unsigned char power_mode;

	mmc_claim_host(host);

	/*
	 * Check for removed cards and newly inserted ones. We check for
	 * removed cards first so we can intelligently re-select the VDD.
	 */
	power_mode = host->ios.power_mode;
	if (power_mode == MMC_POWER_ON)
		mmc_check_cards(host);

	mmc_setup(host);

	/*
	 * Some broken cards process CMD1 even in stand-by state. There is
	 * no reply, but an ILLEGAL_COMMAND error is cached and returned
	 * after next command. We poll for card status here to clear any
	 * possibly pending error.
	 */
	if (power_mode == MMC_POWER_ON)
		mmc_check_cards(host);

	if (!list_empty(&host->cards)) {
		/*
		 * (Re-)calculate the fastest clock rate which the
		 * attached cards and the host support.
		 */
		host->ios.clock = mmc_calculate_clock(host);
		mmc_set_ios(host);
	}

	mmc_release_host(host);

	list_for_each_safe(l, n, &host->cards) {
		struct mmc_card *card = mmc_list_to_card(l);

		/*
		 * If this is a new and good card, register it.
		 */
		if (!mmc_card_present(card) && !mmc_card_dead(card)) {
			if (mmc_register_card(card))
				mmc_card_set_dead(card);
			else
				mmc_card_set_present(card);
		}

		/*
		 * If this card is dead, destroy it.
		 */
		if (mmc_card_dead(card)) {
			list_del(&card->node);
			mmc_remove_card(card);
		}
	}

	/*
	 * If we discover that there are no cards on the
	 * bus, turn off the clock and power down.
	 */
	if (list_empty(&host->cards))
		mmc_power_off(host);
}


/**
 *	mmc_alloc_host - initialise the per-host structure.
 *	@extra: sizeof private data structure
 *	@dev: pointer to host device model structure
 *
 *	Initialise the per-host structure.
 */
struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
{
	struct mmc_host *host;

	host = mmc_alloc_host_sysfs(extra, dev);
	if (host) {
		spin_lock_init(&host->lock);
		init_waitqueue_head(&host->wq);
		INIT_LIST_HEAD(&host->cards);
		INIT_DELAYED_WORK(&host->detect, mmc_rescan);

		/*
		 * By default, hosts do not support SGIO or large requests.
		 * They have to set these according to their abilities.
		 */
		host->max_hw_segs = 1;
		host->max_phys_segs = 1;
		host->max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
		host->max_seg_size = PAGE_CACHE_SIZE;
	}

	return host;
}

EXPORT_SYMBOL(mmc_alloc_host);

/**
 *	mmc_add_host - initialise host hardware
 *	@host: mmc host
 */
int mmc_add_host(struct mmc_host *host)
{
	int ret;

	ret = mmc_add_host_sysfs(host);
	if (ret == 0) {
		mmc_power_off(host);
		mmc_detect_change(host, 0);
	}

	return ret;
}

EXPORT_SYMBOL(mmc_add_host);

/**
 *	mmc_remove_host - remove host hardware
 *	@host: mmc host
 *
 *	Unregister and remove all cards associated with this host,
 *	and power down the MMC bus.
 */
void mmc_remove_host(struct mmc_host *host)
{
	struct list_head *l, *n;

	list_for_each_safe(l, n, &host->cards) {
		struct mmc_card *card = mmc_list_to_card(l);

		mmc_remove_card(card);
	}

	mmc_power_off(host);
	mmc_remove_host_sysfs(host);
}

EXPORT_SYMBOL(mmc_remove_host);

/**
 *	mmc_free_host - free the host structure
 *	@host: mmc host
 *
 *	Free the host once all references to it have been dropped.
 */
void mmc_free_host(struct mmc_host *host)
{
	mmc_flush_scheduled_work();
	mmc_free_host_sysfs(host);
}

EXPORT_SYMBOL(mmc_free_host);

#ifdef CONFIG_PM

/**
 *	mmc_suspend_host - suspend a host
 *	@host: mmc host
 *	@state: suspend mode (PM_SUSPEND_xxx)
 */
int mmc_suspend_host(struct mmc_host *host, pm_message_t state)
{
	mmc_claim_host(host);
	mmc_deselect_cards(host);
	mmc_power_off(host);
	mmc_release_host(host);

	return 0;
}

EXPORT_SYMBOL(mmc_suspend_host);

/**
 *	mmc_resume_host - resume a previously suspended host
 *	@host: mmc host
 */
int mmc_resume_host(struct mmc_host *host)
{
	mmc_rescan(&host->detect.work);

	return 0;
}

EXPORT_SYMBOL(mmc_resume_host);

#endif

MODULE_LICENSE("GPL");