wbsd.c

嵌入式Linux下SD卡的驱动 驱动主要以三星2410板设计的

			}
		}
	}
	
	wbsd_kunmap_sg(host);
	
	/*
	 * The controller stops sending interrupts for
	 * 'FIFO empty' under certain conditions. So we
	 * need to be a bit more pro-active.
	 */
	tasklet_schedule(&host->fifo_tasklet);
}

static void wbsd_prepare_data(struct wbsd_host* host, struct mmc_data* data)
{
	u16 blksize;
	u8 setup;
	unsigned long dmaflags;

	DBGF("blksz %04x blks %04x flags %08x\n",
		1 << data->blksz_bits, data->blocks, data->flags);
	DBGF("tsac %d ms nsac %d clk\n",
		data->timeout_ns / 1000000, data->timeout_clks);
	
	/*
	 * Calculate size.
	 */
	host->size = data->blocks << data->blksz_bits;

	/*
	 * Check timeout values for overflow.
	 * (Yes, some cards cause this value to overflow).
	 */
	if (data->timeout_ns > 127000000)
		wbsd_write_index(host, WBSD_IDX_TAAC, 127);
	else
		wbsd_write_index(host, WBSD_IDX_TAAC, data->timeout_ns/1000000);
	
	if (data->timeout_clks > 255)
		wbsd_write_index(host, WBSD_IDX_NSAC, 255);
	else
		wbsd_write_index(host, WBSD_IDX_NSAC, data->timeout_clks);
	
	/*
	 * Inform the chip of how large blocks will be
	 * sent. It needs this to determine when to
	 * calculate CRC.
	 *
	 * Space for CRC must be included in the size.
	 */
	blksize = (1 << data->blksz_bits) + 2;
	
	wbsd_write_index(host, WBSD_IDX_PBSMSB, (blksize >> 4) & 0xF0);
	wbsd_write_index(host, WBSD_IDX_PBSLSB, blksize & 0xFF);

	/*
	 * Clear the FIFO. This is needed even for DMA
	 * transfers since the chip still uses the FIFO
	 * internally.
	 */
	setup = wbsd_read_index(host, WBSD_IDX_SETUP);
	setup |= WBSD_FIFO_RESET;
	wbsd_write_index(host, WBSD_IDX_SETUP, setup);
	
	/*
	 * DMA transfer?
	 */
	if (host->dma >= 0)
	{	
		/*
		 * The buffer for DMA is only 64 kB.
		 */
		BUG_ON(host->size > 0x10000);
		if (host->size > 0x10000)
		{
			data->error = MMC_ERR_INVALID;
			return;
		}
		
		/*
		 * Transfer data from the SG list to
		 * the DMA buffer.
		 */
		if (data->flags & MMC_DATA_WRITE)
			wbsd_sg_to_dma(host, data);
		
		/*
		 * Initialise the ISA DMA controller.
		 */	
		dmaflags = claim_dma_lock();
		disable_dma(host->dma);
		clear_dma_ff(host->dma);
		if (data->flags & MMC_DATA_READ)
			set_dma_mode(host->dma, DMA_MODE_READ & ~0x40);
		else
			set_dma_mode(host->dma, DMA_MODE_WRITE & ~0x40);
		set_dma_addr(host->dma, host->dma_addr);
		set_dma_count(host->dma, host->size);

		enable_dma(host->dma);
		release_dma_lock(dmaflags);

		/*
		 * Enable DMA on the host.
		 */
		wbsd_write_index(host, WBSD_IDX_DMA, WBSD_DMA_ENABLE);
	}
	else
	{
		/*
		 * This flag is used to keep printk
		 * output to a minimum.
		 */
		host->firsterr = 1;
		
		/*
		 * Initialise the SG list.
		 */
		wbsd_init_sg(host, data);
	
		/*
		 * Turn off DMA.
		 */
		wbsd_write_index(host, WBSD_IDX_DMA, 0);
	
		/*
		 * Set up FIFO threshold levels (and fill
		 * buffer if doing a write).
		 */
		if (data->flags & MMC_DATA_READ)
		{
			wbsd_write_index(host, WBSD_IDX_FIFOEN,
				WBSD_FIFOEN_FULL | 8);
		}
		else
		{
			wbsd_write_index(host, WBSD_IDX_FIFOEN,
				WBSD_FIFOEN_EMPTY | 8);
			wbsd_fill_fifo(host);
		}
	}	
		
	data->error = MMC_ERR_NONE;
}

static void wbsd_finish_data(struct wbsd_host* host, struct mmc_data* data)
{
	unsigned long dmaflags;
	int count;
	u8 status;
	
	WARN_ON(host->mrq == NULL);

	/*
	 * Send a stop command if needed.
	 */
	if (data->stop)
		wbsd_send_command(host, data->stop);

	/*
	 * Wait for the controller to leave data
	 * transfer state.
	 */
	do
	{
		status = wbsd_read_index(host, WBSD_IDX_STATUS);
	} while (status & (WBSD_BLOCK_READ | WBSD_BLOCK_WRITE));
	
	/*
	 * DMA transfer?
	 */
	if (host->dma >= 0)
	{
		/*
		 * Disable DMA on the host.
		 */
		wbsd_write_index(host, WBSD_IDX_DMA, 0);
		
		/*
		 * Turn of ISA DMA controller.
		 */
		dmaflags = claim_dma_lock();
		disable_dma(host->dma);
		clear_dma_ff(host->dma);
		count = get_dma_residue(host->dma);
		release_dma_lock(dmaflags);
		
		/*
		 * Any leftover data?
		 */
		if (count)
		{
			printk(KERN_ERR DRIVER_NAME ": Incomplete DMA "
				"transfer. %d bytes left.\n", count);
			
			data->error = MMC_ERR_FAILED;
		}
		else
		{
			/*
			 * Transfer data from DMA buffer to
			 * SG list.
			 */
			if (data->flags & MMC_DATA_READ)
				wbsd_dma_to_sg(host, data);
			
			data->bytes_xfered = host->size;
		}
	}
	
	DBGF("Ending data transfer (%d bytes)\n", data->bytes_xfered);
	
	wbsd_request_end(host, host->mrq);
}

/*****************************************************************************\
 *                                                                           *
 * MMC layer callbacks                                                       *
 *                                                                           *
\*****************************************************************************/

static void wbsd_request(struct mmc_host* mmc, struct mmc_request* mrq)
{
	struct wbsd_host* host = mmc_priv(mmc);
	struct mmc_command* cmd;

	/*
	 * Disable tasklets to avoid a deadlock.
	 */
	spin_lock_bh(&host->lock);

	BUG_ON(host->mrq != NULL);

	cmd = mrq->cmd;

	host->mrq = mrq;
	
	/*
	 * If there is no card in the slot then
	 * timeout immediatly.
	 */
	if (!(host->flags & WBSD_FCARD_PRESENT))
	{
		cmd->error = MMC_ERR_TIMEOUT;
		goto done;
	}

	/*
	 * Does the request include data?
	 */
	if (cmd->data)
	{
		wbsd_prepare_data(host, cmd->data);
		
		if (cmd->data->error != MMC_ERR_NONE)
			goto done;
	}
	
	wbsd_send_command(host, cmd);

	/*
	 * If this is a data transfer the request
	 * will be finished after the data has
	 * transfered.
	 */	
	if (cmd->data && (cmd->error == MMC_ERR_NONE))
	{
		/*
		 * Dirty fix for hardware bug.
		 */
		if (host->dma == -1)
			tasklet_schedule(&host->fifo_tasklet);

		spin_unlock_bh(&host->lock);

		return;
	}
		
done:
	wbsd_request_end(host, mrq);

	spin_unlock_bh(&host->lock);
}

static void wbsd_set_ios(struct mmc_host* mmc, struct mmc_ios* ios)
{
	struct wbsd_host* host = mmc_priv(mmc);
	u8 clk, setup, pwr;
	
	DBGF("clock %uHz busmode %u powermode %u Vdd %u\n",
		ios->clock, ios->bus_mode, ios->power_mode, ios->vdd);

	spin_lock_bh(&host->lock);

	/*
	 * Reset the chip on each power off.
	 * Should clear out any weird states.
	 */
	if (ios->power_mode == MMC_POWER_OFF)
		wbsd_init_device(host);
	
	if (ios->clock >= 24000000)
		clk = WBSD_CLK_24M;
	else if (ios->clock >= 16000000)
		clk = WBSD_CLK_16M;
	else if (ios->clock >= 12000000)
		clk = WBSD_CLK_12M;
	else
		clk = WBSD_CLK_375K;

	/*
	 * Only write to the clock register when
	 * there is an actual change.
	 */
	if (clk != host->clk)
	{
		wbsd_write_index(host, WBSD_IDX_CLK, clk);
		host->clk = clk;
	}

	/*
	 * Power up card.
	 */
	if (ios->power_mode != MMC_POWER_OFF)
	{
		pwr = inb(host->base + WBSD_CSR);
		pwr &= ~WBSD_POWER_N;
		outb(pwr, host->base + WBSD_CSR);
	}

	/*
	 * MMC cards need to have pin 1 high during init.
	 * Init time corresponds rather nicely with the bus mode.
	 * It wreaks havoc with the card detection though so
	 * that needs to be disabed.
	 */
	setup = wbsd_read_index(host, WBSD_IDX_SETUP);
	if ((ios->power_mode == MMC_POWER_ON) &&
		(ios->bus_mode == MMC_BUSMODE_OPENDRAIN))
	{
		setup |= WBSD_DAT3_H;
		host->flags |= WBSD_FIGNORE_DETECT;
	}
	else
	{
		setup &= ~WBSD_DAT3_H;
		host->flags &= ~WBSD_FIGNORE_DETECT;
	}
	wbsd_write_index(host, WBSD_IDX_SETUP, setup);
	
	spin_unlock_bh(&host->lock);
}

static struct mmc_host_ops wbsd_ops = {
	.request	= wbsd_request,
	.set_ios	= wbsd_set_ios,
};

/*****************************************************************************\
 *                                                                           *
 * Interrupt handling                                                        *
 *                                                                           *
\*****************************************************************************/

/*
 * Helper function for card detection
 */
static void wbsd_detect_card(unsigned long data)
{
	struct wbsd_host *host = (struct wbsd_host*)data;
	
	BUG_ON(host == NULL);
	
	DBG("Executing card detection\n");
	
	mmc_detect_change(host->mmc);	
}

/*
 * Tasklets
 */

static inline struct mmc_data* wbsd_get_data(struct wbsd_host* host)
{
	WARN_ON(!host->mrq);
	if (!host->mrq)
		return NULL;

	WARN_ON(!host->mrq->cmd);
	if (!host->mrq->cmd)
		return NULL;

	WARN_ON(!host->mrq->cmd->data);
	if (!host->mrq->cmd->data)
		return NULL;
	
	return host->mrq->cmd->data;
}

static void wbsd_tasklet_card(unsigned long param)
{
	struct wbsd_host* host = (struct wbsd_host*)param;
	u8 csr;
	
	spin_lock(&host->lock);
	
	if (host->flags & WBSD_FIGNORE_DETECT)
	{
		spin_unlock(&host->lock);
		return;
	}
	
	csr = inb(host->base + WBSD_CSR);
	WARN_ON(csr == 0xff);
	
	if (csr & WBSD_CARDPRESENT)
	{
		if (!(host->flags & WBSD_FCARD_PRESENT))
		{
			DBG("Card inserted\n");
			host->flags |= WBSD_FCARD_PRESENT;
			
			/*
			 * Delay card detection to allow electrical connections
			 * to stabilise.
			 */
			mod_timer(&host->timer, jiffies + HZ/2);
		}
		
		spin_unlock(&host->lock);
	}
	else if (host->flags & WBSD_FCARD_PRESENT)
	{
		DBG("Card removed\n");
		host->flags &= ~WBSD_FCARD_PRESENT;
		
		if (host->mrq)
		{
			printk(KERN_ERR DRIVER_NAME
				": Card removed during transfer!\n");
			wbsd_reset(host);
			
			host->mrq->cmd->error = MMC_ERR_FAILED;
			tasklet_schedule(&host->finish_tasklet);
		}
		
		/*
		 * Unlock first since we might get a call back.
		 */
		spin_unlock(&host->lock);

		mmc_detect_change(host->mmc);
	}
}

static void wbsd_tasklet_fifo(unsigned long param)
{
	struct wbsd_host* host = (struct wbsd_host*)param;
	struct mmc_data* data;
	
	spin_lock(&host->lock);
		
	if (!host->mrq)
		goto end;
	
	data = wbsd_get_data(host);
	if (!data)
		goto end;

	if (data->flags & MMC_DATA_WRITE)
		wbsd_fill_fifo(host);
	else
		wbsd_empty_fifo(host);

	/*
	 * Done?
	 */
	if (host->size == data->bytes_xfered)
	{
		wbsd_write_index(host, WBSD_IDX_FIFOEN, 0);
		tasklet_schedule(&host->finish_tasklet);
	}

end:	
	spin_unlock(&host->lock);
}

static void wbsd_tasklet_crc(unsigned long param)
{
	struct wbsd_host* host = (struct wbsd_host*)param;
	struct mmc_data* data;
	
	spin_lock(&host->lock);
	
	if (!host->mrq)
		goto end;
	
	data = wbsd_get_data(host);
	if (!data)
		goto end;
	
	DBGF("CRC error\n");

	data->error = MMC_ERR_BADCRC;
	
	tasklet_schedule(&host->finish_tasklet);

end:		
	spin_unlock(&host->lock);
}

static void wbsd_tasklet_timeout(unsigned long param)
{
	struct wbsd_host* host = (struct wbsd_host*)param;
	struct mmc_data* data;
	
	spin_lock(&host->lock);
	
	if (!host->mrq)
		goto end;
	
	data = wbsd_get_data(host);
	if (!data)
		goto end;
	
	DBGF("Timeout\n");

	data->error = MMC_ERR_TIMEOUT;
	
	tasklet_schedule(&host->finish_tasklet);

end:	
	spin_unlock(&host->lock);
}

static void wbsd_tasklet_finish(unsigned long param)
{
	struct wbsd_host* host = (struct wbsd_host*)param;
	struct mmc_data* data;
	
	spin_lock(&host->lock);
	
	WARN_ON(!host->mrq);
	if (!host->mrq)
		goto end;
	
	data = wbsd_get_data(host);
	if (!data)
		goto end;

	wbsd_finish_data(host, data);
	
end:	
	spin_unlock(&host->lock);
}

static void wbsd_tasklet_block(unsigned long param)
{
	struct wbsd_host* host = (struct wbsd_host*)param;
	struct mmc_data* data;
	
	spin_lock(&host->lock);

	if ((wbsd_read_index(host, WBSD_IDX_CRCSTATUS) & WBSD_CRC_MASK) !=
		WBSD_CRC_OK)
	{
		data = wbsd_get_data(host);
		if (!data)
			goto end;
		
		DBGF("CRC error\n");

		data->error = MMC_ERR_BADCRC;
	
		tasklet_schedule(&host->finish_tasklet);
	}

end:	
	spin_unlock(&host->lock);
}

/*
 * Interrupt handling
 */

static irqreturn_t wbsd_irq(int irq, void *dev_id, struct pt_regs *regs)
{
	struct wbsd_host* host = dev_id;
	int isr;
	
	isr = inb(host->base + WBSD_ISR);

	/*
	 * Was it actually our hardware that caused the interrupt?
	 */
	if (isr == 0xff || isr == 0x00)
		return IRQ_NONE;
	
	host->isr |= isr;

	/*
	 * Schedule tasklets as needed.
	 */
	if (isr & WBSD_INT_CARD)
		tasklet_schedule(&host->card_tasklet);
	if (isr & WBSD_INT_FIFO_THRE)
		tasklet_schedule(&host->fifo_tasklet);
	if (isr & WBSD_INT_CRC)
		tasklet_hi_schedule(&host->crc_tasklet);
	if (isr & WBSD_INT_TIMEOUT)
		tasklet_hi_schedule(&host->timeout_tasklet);
	if (isr & WBSD_INT_BUSYEND)
		tasklet_hi_schedule(&host->block_tasklet);
	if (isr & WBSD_INT_TC)
		tasklet_schedule(&host->finish_tasklet);
	
	return IRQ_HANDLED;
}

/*****************************************************************************\
 *                                                                           *
 * Device initialisation and shutdown                                        *
 *                                                                           *
\*****************************************************************************/

/*
 * Allocate/free MMC structure.
 */

static int __devinit wbsd_alloc_mmc(struct device* dev)
{
	struct mmc_host* mmc;
	struct wbsd_host* host;
	
	/*
	 * Allocate MMC structure.
	 */
	mmc = mmc_alloc_host(sizeof(struct wbsd_host), dev);
	if (!mmc)
		return -ENOMEM;
	
	host = mmc_priv(mmc);
	host->mmc = mmc;

	host->dma = -1;

	/*
	 * Set host parameters.
	 */
	mmc->ops = &wbsd_ops;
	mmc->f_min = 375000;
	mmc->f_max = 24000000;
	mmc->ocr_avail = MMC_VDD_32_33|MMC_VDD_33_34;
	
	spin_lock_init(&host->lock);
	
	/*
	 * Set up detection timer
	 */
	init_timer(&host->timer);
	host->timer.data = (unsigned long)host;
	host->timer.function = wbsd_detect_card;
	
	/*
	 * Maximum number of segments. Worst case is one sector per segment
	 * so this will be 64kB/512.
	 */
	mmc->max_hw_segs = 128;
	mmc->max_phys_segs = 128;
	
	/*