pxamci.c

来自「linux 内核源代码」· C语言 代码 · 共 685 行 · 第 1/2 页

/*
 *  linux/drivers/mmc/host/pxa.c - PXA MMCI driver
 *
 *  Copyright (C) 2003 Russell King, All Rights Reserved.
 *
 * 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.
 *
 *  This hardware is really sick:
 *   - No way to clear interrupts.
 *   - Have to turn off the clock whenever we touch the device.
 *   - Doesn't tell you how many data blocks were transferred.
 *  Yuck!
 *
 *	1 and 3 byte data transfers not supported
 *	max block length up to 1023
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/mmc/host.h>

#include <asm/dma.h>
#include <asm/io.h>
#include <asm/sizes.h>

#include <asm/arch/pxa-regs.h>
#include <asm/arch/mmc.h>

#include "pxamci.h"

#define DRIVER_NAME	"pxa2xx-mci"

#define NR_SG	1
#define CLKRT_OFF	(~0)

struct pxamci_host {
	struct mmc_host		*mmc;
	spinlock_t		lock;
	struct resource		*res;
	void __iomem		*base;
	struct clk		*clk;
	unsigned long		clkrate;
	int			irq;
	int			dma;
	unsigned int		clkrt;
	unsigned int		cmdat;
	unsigned int		imask;
	unsigned int		power_mode;
	struct pxamci_platform_data *pdata;

	struct mmc_request	*mrq;
	struct mmc_command	*cmd;
	struct mmc_data		*data;

	dma_addr_t		sg_dma;
	struct pxa_dma_desc	*sg_cpu;
	unsigned int		dma_len;

	unsigned int		dma_dir;
};

static void pxamci_stop_clock(struct pxamci_host *host)
{
	if (readl(host->base + MMC_STAT) & STAT_CLK_EN) {
		unsigned long timeout = 10000;
		unsigned int v;

		writel(STOP_CLOCK, host->base + MMC_STRPCL);

		do {
			v = readl(host->base + MMC_STAT);
			if (!(v & STAT_CLK_EN))
				break;
			udelay(1);
		} while (timeout--);

		if (v & STAT_CLK_EN)
			dev_err(mmc_dev(host->mmc), "unable to stop clock\n");
	}
}

static void pxamci_enable_irq(struct pxamci_host *host, unsigned int mask)
{
	unsigned long flags;

	spin_lock_irqsave(&host->lock, flags);
	host->imask &= ~mask;
	writel(host->imask, host->base + MMC_I_MASK);
	spin_unlock_irqrestore(&host->lock, flags);
}

static void pxamci_disable_irq(struct pxamci_host *host, unsigned int mask)
{
	unsigned long flags;

	spin_lock_irqsave(&host->lock, flags);
	host->imask |= mask;
	writel(host->imask, host->base + MMC_I_MASK);
	spin_unlock_irqrestore(&host->lock, flags);
}

static void pxamci_setup_data(struct pxamci_host *host, struct mmc_data *data)
{
	unsigned int nob = data->blocks;
	unsigned long long clks;
	unsigned int timeout;
	u32 dcmd;
	int i;

	host->data = data;

	if (data->flags & MMC_DATA_STREAM)
		nob = 0xffff;

	writel(nob, host->base + MMC_NOB);
	writel(data->blksz, host->base + MMC_BLKLEN);

	clks = (unsigned long long)data->timeout_ns * host->clkrate;
	do_div(clks, 1000000000UL);
	timeout = (unsigned int)clks + (data->timeout_clks << host->clkrt);
	writel((timeout + 255) / 256, host->base + MMC_RDTO);

	if (data->flags & MMC_DATA_READ) {
		host->dma_dir = DMA_FROM_DEVICE;
		dcmd = DCMD_INCTRGADDR | DCMD_FLOWTRG;
		DRCMRTXMMC = 0;
		DRCMRRXMMC = host->dma | DRCMR_MAPVLD;
	} else {
		host->dma_dir = DMA_TO_DEVICE;
		dcmd = DCMD_INCSRCADDR | DCMD_FLOWSRC;
		DRCMRRXMMC = 0;
		DRCMRTXMMC = host->dma | DRCMR_MAPVLD;
	}

	dcmd |= DCMD_BURST32 | DCMD_WIDTH1;

	host->dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
				   host->dma_dir);

	for (i = 0; i < host->dma_len; i++) {
		unsigned int length = sg_dma_len(&data->sg[i]);
		host->sg_cpu[i].dcmd = dcmd | length;
		if (length & 31 && !(data->flags & MMC_DATA_READ))
			host->sg_cpu[i].dcmd |= DCMD_ENDIRQEN;
		if (data->flags & MMC_DATA_READ) {
			host->sg_cpu[i].dsadr = host->res->start + MMC_RXFIFO;
			host->sg_cpu[i].dtadr = sg_dma_address(&data->sg[i]);
		} else {
			host->sg_cpu[i].dsadr = sg_dma_address(&data->sg[i]);
			host->sg_cpu[i].dtadr = host->res->start + MMC_TXFIFO;
		}
		host->sg_cpu[i].ddadr = host->sg_dma + (i + 1) *
					sizeof(struct pxa_dma_desc);
	}
	host->sg_cpu[host->dma_len - 1].ddadr = DDADR_STOP;
	wmb();

	DDADR(host->dma) = host->sg_dma;
	DCSR(host->dma) = DCSR_RUN;
}

static void pxamci_start_cmd(struct pxamci_host *host, struct mmc_command *cmd, unsigned int cmdat)
{
	WARN_ON(host->cmd != NULL);
	host->cmd = cmd;

	if (cmd->flags & MMC_RSP_BUSY)
		cmdat |= CMDAT_BUSY;

#define RSP_TYPE(x)	((x) & ~(MMC_RSP_BUSY|MMC_RSP_OPCODE))
	switch (RSP_TYPE(mmc_resp_type(cmd))) {
	case RSP_TYPE(MMC_RSP_R1): /* r1, r1b, r6, r7 */
		cmdat |= CMDAT_RESP_SHORT;
		break;
	case RSP_TYPE(MMC_RSP_R3):
		cmdat |= CMDAT_RESP_R3;
		break;
	case RSP_TYPE(MMC_RSP_R2):
		cmdat |= CMDAT_RESP_R2;
		break;
	default:
		break;
	}

	writel(cmd->opcode, host->base + MMC_CMD);
	writel(cmd->arg >> 16, host->base + MMC_ARGH);
	writel(cmd->arg & 0xffff, host->base + MMC_ARGL);
	writel(cmdat, host->base + MMC_CMDAT);
	writel(host->clkrt, host->base + MMC_CLKRT);

	writel(START_CLOCK, host->base + MMC_STRPCL);

	pxamci_enable_irq(host, END_CMD_RES);
}

static void pxamci_finish_request(struct pxamci_host *host, struct mmc_request *mrq)
{
	host->mrq = NULL;
	host->cmd = NULL;
	host->data = NULL;
	mmc_request_done(host->mmc, mrq);
}

static int pxamci_cmd_done(struct pxamci_host *host, unsigned int stat)
{
	struct mmc_command *cmd = host->cmd;
	int i;
	u32 v;

	if (!cmd)
		return 0;

	host->cmd = NULL;

	/*
	 * Did I mention this is Sick.  We always need to
	 * discard the upper 8 bits of the first 16-bit word.
	 */
	v = readl(host->base + MMC_RES) & 0xffff;
	for (i = 0; i < 4; i++) {
		u32 w1 = readl(host->base + MMC_RES) & 0xffff;
		u32 w2 = readl(host->base + MMC_RES) & 0xffff;
		cmd->resp[i] = v << 24 | w1 << 8 | w2 >> 8;
		v = w2;
	}

	if (stat & STAT_TIME_OUT_RESPONSE) {
		cmd->error = -ETIMEDOUT;
	} else if (stat & STAT_RES_CRC_ERR && cmd->flags & MMC_RSP_CRC) {
#ifdef CONFIG_PXA27x
		/*
		 * workaround for erratum #42:
		 * Intel PXA27x Family Processor Specification Update Rev 001
		 * A bogus CRC error can appear if the msb of a 136 bit
		 * response is a one.
		 */
		if (cmd->flags & MMC_RSP_136 && cmd->resp[0] & 0x80000000) {
			pr_debug("ignoring CRC from command %d - *risky*\n", cmd->opcode);
		} else
#endif
		cmd->error = -EILSEQ;
	}

	pxamci_disable_irq(host, END_CMD_RES);
	if (host->data && !cmd->error) {
		pxamci_enable_irq(host, DATA_TRAN_DONE);
	} else {
		pxamci_finish_request(host, host->mrq);
	}

	return 1;
}

static int pxamci_data_done(struct pxamci_host *host, unsigned int stat)
{
	struct mmc_data *data = host->data;

	if (!data)
		return 0;

	DCSR(host->dma) = 0;
	dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
		     host->dma_dir);

	if (stat & STAT_READ_TIME_OUT)
		data->error = -ETIMEDOUT;
	else if (stat & (STAT_CRC_READ_ERROR|STAT_CRC_WRITE_ERROR))
		data->error = -EILSEQ;

	/*
	 * There appears to be a hardware design bug here.  There seems to
	 * be no way to find out how much data was transferred to the card.
	 * This means that if there was an error on any block, we mark all
	 * data blocks as being in error.
	 */
	if (!data->error)
		data->bytes_xfered = data->blocks * data->blksz;
	else
		data->bytes_xfered = 0;

	pxamci_disable_irq(host, DATA_TRAN_DONE);

	host->data = NULL;
	if (host->mrq->stop) {
		pxamci_stop_clock(host);
		pxamci_start_cmd(host, host->mrq->stop, host->cmdat);
	} else {
		pxamci_finish_request(host, host->mrq);
	}

	return 1;
}

static irqreturn_t pxamci_irq(int irq, void *devid)
{
	struct pxamci_host *host = devid;
	unsigned int ireg;
	int handled = 0;

	ireg = readl(host->base + MMC_I_REG) & ~readl(host->base + MMC_I_MASK);

	if (ireg) {
		unsigned stat = readl(host->base + MMC_STAT);

		pr_debug("PXAMCI: irq %08x stat %08x\n", ireg, stat);

		if (ireg & END_CMD_RES)
			handled |= pxamci_cmd_done(host, stat);
		if (ireg & DATA_TRAN_DONE)
			handled |= pxamci_data_done(host, stat);
		if (ireg & SDIO_INT) {
			mmc_signal_sdio_irq(host->mmc);
			handled = 1;
		}
	}

	return IRQ_RETVAL(handled);
}

static void pxamci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
	struct pxamci_host *host = mmc_priv(mmc);
	unsigned int cmdat;

	WARN_ON(host->mrq != NULL);

	host->mrq = mrq;

	pxamci_stop_clock(host);

	cmdat = host->cmdat;
	host->cmdat &= ~CMDAT_INIT;

	if (mrq->data) {
		pxamci_setup_data(host, mrq->data);