C++ OMAP_MMC_READ函数代码示例

static void
mmc_omap_send_abort(struct mmc_omap_host *host, int maxloops)
{
	struct mmc_omap_slot *slot = host->current_slot;
	unsigned int restarts, passes, timeout;
	u16 stat = 0;

	/* Sending abort takes 80 clocks. Have some extra and round up */
	timeout = (120*1000000 + slot->fclk_freq - 1)/slot->fclk_freq;
	restarts = 0;
	while (restarts < maxloops) {
		OMAP_MMC_WRITE(host, STAT, 0xFFFF);
		OMAP_MMC_WRITE(host, CMD, (3 << 12) | (1 << 7));

		passes = 0;
		while (passes < timeout) {
			stat = OMAP_MMC_READ(host, STAT);
			if (stat & OMAP_MMC_STAT_END_OF_CMD)
				goto out;
			udelay(1);
			passes++;
		}

		restarts++;
	}
out:
	OMAP_MMC_WRITE(host, STAT, stat);
}

static inline void set_cmd_timeout(struct mmc_omap_host *host, struct mmc_request *req)
{
	u16 reg;

	reg = OMAP_MMC_READ(host, SDIO);
	reg &= ~(1 << 5);
	OMAP_MMC_WRITE(host, SDIO, reg);
	/* Set maximum timeout */
	OMAP_MMC_WRITE(host, CTO, 0xff);
}

static void
mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd)
{
	host->cmd = NULL;

	del_timer(&host->cmd_abort_timer);

	if (cmd->flags & MMC_RSP_PRESENT) {
		if (cmd->flags & MMC_RSP_136) {
			/* response type 2 */
			cmd->resp[3] =
				OMAP_MMC_READ(host, RSP0) |
				(OMAP_MMC_READ(host, RSP1) << 16);
			cmd->resp[2] =
				OMAP_MMC_READ(host, RSP2) |
				(OMAP_MMC_READ(host, RSP3) << 16);
			cmd->resp[1] =
				OMAP_MMC_READ(host, RSP4) |
				(OMAP_MMC_READ(host, RSP5) << 16);
			cmd->resp[0] =
				OMAP_MMC_READ(host, RSP6) |
				(OMAP_MMC_READ(host, RSP7) << 16);
		} else {
			/* response types 1, 1b, 3, 4, 5, 6 */
			cmd->resp[0] =
				OMAP_MMC_READ(host, RSP6) |
				(OMAP_MMC_READ(host, RSP7) << 16);
		}
	}

	if (host->data == NULL || cmd->error) {
		struct mmc_host *mmc;

		if (host->data != NULL)
			mmc_omap_abort_xfer(host, host->data);
		host->mrq = NULL;
		mmc = host->mmc;
		mmc_omap_release_slot(host->current_slot, 1);
		mmc_request_done(mmc, cmd->mrq);
	}
}

static void mmc_omap_set_power(struct mmc_omap_slot *slot, int power_on,
				int vdd)
{
	struct mmc_omap_host *host;

	host = slot->host;

	if (slot->pdata->set_power != NULL)
		slot->pdata->set_power(mmc_dev(slot->mmc), slot->id, power_on,
					vdd);
	if (mmc_omap2()) {
		u16 w;

		if (power_on) {
			w = OMAP_MMC_READ(host, CON);
			OMAP_MMC_WRITE(host, CON, w | (1 << 11));
		} else {
			w = OMAP_MMC_READ(host, CON);
			OMAP_MMC_WRITE(host, CON, w & ~(1 << 11));
		}
	}
}

static inline void set_data_timeout(struct mmc_omap_host *host, struct mmc_request *req)
{
	unsigned int timeout, cycle_ns;
	u16 reg;

	cycle_ns = 1000000000 / host->current_slot->fclk_freq;
	timeout = req->data->timeout_ns / cycle_ns;
	timeout += req->data->timeout_clks;

	/* Check if we need to use timeout multiplier register */
	reg = OMAP_MMC_READ(host, SDIO);
	if (timeout > 0xffff) {
		reg |= (1 << 5);
		timeout /= 1024;
	} else
		reg &= ~(1 << 5);
	OMAP_MMC_WRITE(host, SDIO, reg);
	OMAP_MMC_WRITE(host, DTO, timeout);
}

static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed)
{
	struct mmc_omap_host *host = slot->host;
	unsigned long flags;

	if (claimed)
		goto no_claim;
	spin_lock_irqsave(&host->slot_lock, flags);
	while (host->mmc != NULL) {
		spin_unlock_irqrestore(&host->slot_lock, flags);
		wait_event(host->slot_wq, host->mmc == NULL);
		spin_lock_irqsave(&host->slot_lock, flags);
	}
	host->mmc = slot->mmc;
	spin_unlock_irqrestore(&host->slot_lock, flags);
no_claim:
	del_timer(&host->clk_timer);
	if (host->current_slot != slot || !claimed)
		mmc_omap_fclk_offdelay(host->current_slot);

	if (host->current_slot != slot) {
		OMAP_MMC_WRITE(host, CON, slot->saved_con & 0xFC00);
		if (host->pdata->switch_slot != NULL)
			host->pdata->switch_slot(mmc_dev(slot->mmc), slot->id);
		host->current_slot = slot;
	}

	if (claimed) {
		mmc_omap_fclk_enable(host, 1);

		/* Doing the dummy read here seems to work around some bug
		 * at least in OMAP24xx silicon where the command would not
		 * start after writing the CMD register. Sigh. */
		OMAP_MMC_READ(host, CON);

		OMAP_MMC_WRITE(host, CON, slot->saved_con);
	} else
		mmc_omap_fclk_enable(host, 0);
}

static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed)
{
	struct mmc_omap_host *host = slot->host;
	unsigned long flags;

	if (claimed)
		goto no_claim;
	spin_lock_irqsave(&host->slot_lock, flags);
	while (host->mmc != NULL) {
		spin_unlock_irqrestore(&host->slot_lock, flags);
		wait_event(host->slot_wq, host->mmc == NULL);
		spin_lock_irqsave(&host->slot_lock, flags);
	}
	host->mmc = slot->mmc;
	spin_unlock_irqrestore(&host->slot_lock, flags);
no_claim:
	del_timer(&host->clk_timer);
	if (host->current_slot != slot || !claimed)
		mmc_omap_fclk_offdelay(host->current_slot);

	if (host->current_slot != slot) {
		OMAP_MMC_WRITE(host, CON, slot->saved_con & 0xFC00);
		if (host->pdata->switch_slot != NULL)
			host->pdata->switch_slot(mmc_dev(slot->mmc), slot->id);
		host->current_slot = slot;
	}

	if (claimed) {
		mmc_omap_fclk_enable(host, 1);

		OMAP_MMC_READ(host, CON);

		OMAP_MMC_WRITE(host, CON, slot->saved_con);
	} else
		mmc_omap_fclk_enable(host, 0);
}

static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
{
	struct mmc_omap_host * host = (struct mmc_omap_host *)dev_id;
	u16 status;
	int end_command;
	int end_transfer;
	int transfer_error, cmd_error;

	if (host->cmd == NULL && host->data == NULL) {
		status = OMAP_MMC_READ(host, STAT);
		dev_info(mmc_dev(host->slots[0]->mmc),
			 "Spurious IRQ 0x%04x\n", status);
		if (status != 0) {
			OMAP_MMC_WRITE(host, STAT, status);
			OMAP_MMC_WRITE(host, IE, 0);
		}
		return IRQ_HANDLED;
	}

	end_command = 0;
	end_transfer = 0;
	transfer_error = 0;
	cmd_error = 0;

	while ((status = OMAP_MMC_READ(host, STAT)) != 0) {
		int cmd;

		OMAP_MMC_WRITE(host, STAT, status);
		if (host->cmd != NULL)
			cmd = host->cmd->opcode;
		else
			cmd = -1;
#ifdef CONFIG_MMC_DEBUG
		dev_dbg(mmc_dev(host->mmc), "MMC IRQ %04x (CMD %d): ",
			status, cmd);
		mmc_omap_report_irq(status);
		printk("\n");
#endif
		if (host->total_bytes_left) {
			if ((status & OMAP_MMC_STAT_A_FULL) ||
			    (status & OMAP_MMC_STAT_END_OF_DATA))
				mmc_omap_xfer_data(host, 0);
			if (status & OMAP_MMC_STAT_A_EMPTY)
				mmc_omap_xfer_data(host, 1);
		}

		if (status & OMAP_MMC_STAT_END_OF_DATA)
			end_transfer = 1;

		if (status & OMAP_MMC_STAT_DATA_TOUT) {
			dev_dbg(mmc_dev(host->mmc), "data timeout (CMD%d)\n",
				cmd);
			if (host->data) {
				host->data->error = -ETIMEDOUT;
				transfer_error = 1;
			}
		}

		if (status & OMAP_MMC_STAT_DATA_CRC) {
			if (host->data) {
				host->data->error = -EILSEQ;
				dev_dbg(mmc_dev(host->mmc),
					 "data CRC error, bytes left %d\n",
					host->total_bytes_left);
				transfer_error = 1;
			} else {
				dev_dbg(mmc_dev(host->mmc), "data CRC error\n");
			}
		}

		if (status & OMAP_MMC_STAT_CMD_TOUT) {
			/* Timeouts are routine with some commands */
			if (host->cmd) {
				struct mmc_omap_slot *slot =
					host->current_slot;
				if (slot == NULL ||
				    !mmc_omap_cover_is_open(slot))
					dev_err(mmc_dev(host->mmc),
						"command timeout (CMD%d)\n",
						cmd);
				host->cmd->error = -ETIMEDOUT;
				end_command = 1;
				cmd_error = 1;
			}
		}

		if (status & OMAP_MMC_STAT_CMD_CRC) {
			if (host->cmd) {
				dev_err(mmc_dev(host->mmc),
					"command CRC error (CMD%d, arg 0x%08x)\n",
					cmd, host->cmd->arg);
				host->cmd->error = -EILSEQ;
				end_command = 1;
				cmd_error = 1;
			} else
				dev_err(mmc_dev(host->mmc),
					"command CRC error without cmd?\n");
		}

		if (status & OMAP_MMC_STAT_CARD_ERR) {
//.........这里部分代码省略.........

static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
	struct mmc_omap_slot *slot = mmc_priv(mmc);
	struct mmc_omap_host *host = slot->host;
	int i, dsor;
	int clk_enabled;

	mmc_omap_select_slot(slot, 0);

	dsor = mmc_omap_calc_divisor(mmc, ios);

	if (ios->vdd != slot->vdd)
		slot->vdd = ios->vdd;

	clk_enabled = 0;
	switch (ios->power_mode) {
	case MMC_POWER_OFF:
		mmc_omap_set_power(slot, 0, ios->vdd);
		break;
	case MMC_POWER_UP:
		/* Cannot touch dsor yet, just power up MMC */
		mmc_omap_set_power(slot, 1, ios->vdd);
		goto exit;
	case MMC_POWER_ON:
		mmc_omap_fclk_enable(host, 1);
		clk_enabled = 1;
		dsor |= 1 << 11;
		break;
	}

	if (slot->bus_mode != ios->bus_mode) {
		if (slot->pdata->set_bus_mode != NULL)
			slot->pdata->set_bus_mode(mmc_dev(mmc), slot->id,
						  ios->bus_mode);
		slot->bus_mode = ios->bus_mode;
	}

	/* On insanely high arm_per frequencies something sometimes
	 * goes somehow out of sync, and the POW bit is not being set,
	 * which results in the while loop below getting stuck.
	 * Writing to the CON register twice seems to do the trick. */
	for (i = 0; i < 2; i++)
		OMAP_MMC_WRITE(host, CON, dsor);
	slot->saved_con = dsor;
	if (ios->power_mode == MMC_POWER_ON) {
		/* worst case at 400kHz, 80 cycles makes 200 microsecs */
		int usecs = 250;

		/* Send clock cycles, poll completion */
		OMAP_MMC_WRITE(host, IE, 0);
		OMAP_MMC_WRITE(host, STAT, 0xffff);
		OMAP_MMC_WRITE(host, CMD, 1 << 7);
		while (usecs > 0 && (OMAP_MMC_READ(host, STAT) & 1) == 0) {
			udelay(1);
			usecs--;
		}
		OMAP_MMC_WRITE(host, STAT, 1);
	}

exit:
	mmc_omap_release_slot(slot, clk_enabled);
}