自学教程：C++ DoC_Delay函数代码示例

static int DoC_Command(struct DiskOnChip *doc, unsigned char command,			      unsigned char xtraflags){	void __iomem *docptr = doc->virtadr;	if (DoC_is_2000(doc))		xtraflags |= CDSN_CTRL_FLASH_IO;	/* Assert the CLE (Command Latch Enable) line to the flash chip */	WriteDOC(xtraflags | CDSN_CTRL_CLE | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */	if (DoC_is_Millennium(doc))		WriteDOC(command, docptr, CDSNSlowIO);	/* Send the command */	WriteDOC_(command, docptr, doc->ioreg);	if (DoC_is_Millennium(doc))		WriteDOC(command, docptr, WritePipeTerm);	/* Lower the CLE line */	WriteDOC(xtraflags | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */	/* Wait for the chip to respond - Software requirement 11.4.1 (extended for any command) */	return DoC_WaitReady(doc);}

/* DoC_IdentChip: Identify a given NAND chip given {floor,chip} */static int DoC_IdentChip(struct DiskOnChip *doc, int floor, int chip){	int mfr, id, i, j;	volatile char dummy;	/* Page in the required floor/chip	   FIXME: is this supported by Millennium ?? */	DoC_SelectFloor(doc->virtadr, floor);	DoC_SelectChip(doc->virtadr, chip);	/* Reset the chip, see Software Requirement 11.4 item 1. */	DoC_Command(doc->virtadr, NAND_CMD_RESET, CDSN_CTRL_WP);	DoC_WaitReady(doc->virtadr);	/* Read the NAND chip ID: 1. Send ReadID command */	DoC_Command(doc->virtadr, NAND_CMD_READID, CDSN_CTRL_WP);	/* Read the NAND chip ID: 2. Send address byte zero */	DoC_Address(doc->virtadr, 1, 0x00, CDSN_CTRL_WP, 0x00);	/* Read the manufacturer and device id codes of the flash device through	   CDSN IO register see Software Requirement 11.4 item 5.*/	dummy = ReadDOC(doc->virtadr, ReadPipeInit);	DoC_Delay(doc->virtadr, 2);	mfr = ReadDOC(doc->virtadr, Mil_CDSN_IO);	DoC_Delay(doc->virtadr, 2);	id  = ReadDOC(doc->virtadr, Mil_CDSN_IO);	dummy = ReadDOC(doc->virtadr, LastDataRead);	/* No response - return failure */	if (mfr == 0xff || mfr == 0)		return 0;	/* FIXME: to deal with multi-flash on multi-Millennium case more carefully */	for (i = 0; nand_flash_ids[i].name != NULL; i++) {		if ( id == nand_flash_ids[i].id) {			/* Try to identify manufacturer */			for (j = 0; nand_manuf_ids[j].id != 0x0; j++) {				if (nand_manuf_ids[j].id == mfr)					break;			}			printk(KERN_INFO "Flash chip found: Manufacturer ID: %2.2X, "			       "Chip ID: %2.2X (%s:%s)/n",			       mfr, id, nand_manuf_ids[j].name, nand_flash_ids[i].name);			doc->mfr = mfr;			doc->id = id;			doc->chipshift = ffs((nand_flash_ids[i].chipsize << 20)) - 1;			break;		}	}	if (nand_flash_ids[i].name == NULL)		return 0;	else		return 1;}

static void DoC_Command(void __iomem * docptr, unsigned char command,			       unsigned char xtraflags){	/* Assert the CLE (Command Latch Enable) line to the flash chip */	WriteDOC(xtraflags | CDSN_CTRL_CLE | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(docptr, 4);	/* Send the command */	WriteDOC(command, docptr, Mil_CDSN_IO);	WriteDOC(0x00, docptr, WritePipeTerm);	/* Lower the CLE line */	WriteDOC(xtraflags | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(docptr, 4);}

static int DoC_Address(struct DiskOnChip *doc, int numbytes, unsigned long ofs,		       unsigned char xtraflags1, unsigned char xtraflags2){	int i;	void __iomem *docptr = doc->virtadr;	if (DoC_is_2000(doc))		xtraflags1 |= CDSN_CTRL_FLASH_IO;	/* Assert the ALE (Address Latch Enable) line to the flash chip */	WriteDOC(xtraflags1 | CDSN_CTRL_ALE | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(doc, 4);	/* Software requirement 11.4.3 for Millennium */	/* Send the address */	/* Devices with 256-byte page are addressed as:	   Column (bits 0-7), Page (bits 8-15, 16-23, 24-31)	   * there is no device on the market with page256	   and more than 24 bits.	   Devices with 512-byte page are addressed as:	   Column (bits 0-7), Page (bits 9-16, 17-24, 25-31)	   * 25-31 is sent only if the chip support it.	   * bit 8 changes the read command to be sent	   (NAND_CMD_READ0 or NAND_CMD_READ1).	 */	if (numbytes == ADDR_COLUMN || numbytes == ADDR_COLUMN_PAGE) {		if (DoC_is_Millennium(doc))			WriteDOC(ofs & 0xff, docptr, CDSNSlowIO);		WriteDOC_(ofs & 0xff, docptr, doc->ioreg);	}	if (doc->page256) {		ofs = ofs >> 8;	} else {

/* DoC_SelectChip: Select a given flash chip within the current floor */static int DoC_SelectChip(void __iomem * docptr, int chip){	/* Select the individual flash chip requested */	WriteDOC(chip, docptr, CDSNDeviceSelect);	DoC_Delay(docptr, 4);	/* Wait for it to be ready */	return DoC_WaitReady(docptr);}

static inline int DoC_WaitReady(void __iomem * docptr){	/* This is inline, to optimise the common case, where it's ready instantly */	int ret = 0;	/* 4 read form NOP register should be issued in prior to the read from CDSNControl	   see Software Requirement 11.4 item 2. */	DoC_Delay(docptr, 4);	if (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B))		/* Call the out-of-line routine to wait */		ret = _DoC_WaitReady(docptr);	/* issue 2 read from NOP register after reading from CDSNControl register	   see Software Requirement 11.4 item 2. */	DoC_Delay(docptr, 2);	return ret;}

static inline void DoC_Address(void __iomem * docptr, int numbytes, unsigned long ofs,			       unsigned char xtraflags1, unsigned char xtraflags2){	/* Assert the ALE (Address Latch Enable) line to the flash chip */	WriteDOC(xtraflags1 | CDSN_CTRL_ALE | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(docptr, 4);	/* Send the address */	switch (numbytes)	    {	    case 1:		    /* Send single byte, bits 0-7. */		    WriteDOC(ofs & 0xff, docptr, Mil_CDSN_IO);		    WriteDOC(0x00, docptr, WritePipeTerm);		    break;	    case 2:		    /* Send bits 9-16 followed by 17-23 */		    WriteDOC((ofs >> 9)  & 0xff, docptr, Mil_CDSN_IO);		    WriteDOC((ofs >> 17) & 0xff, docptr, Mil_CDSN_IO);		    WriteDOC(0x00, docptr, WritePipeTerm);		break;	    case 3:		    /* Send 0-7, 9-16, then 17-23 */		    WriteDOC(ofs & 0xff, docptr, Mil_CDSN_IO);		    WriteDOC((ofs >> 9)  & 0xff, docptr, Mil_CDSN_IO);		    WriteDOC((ofs >> 17) & 0xff, docptr, Mil_CDSN_IO);		    WriteDOC(0x00, docptr, WritePipeTerm);		break;	    default:		return;	    }	/* Lower the ALE line */	WriteDOC(xtraflags1 | xtraflags2 | CDSN_CTRL_CE, docptr, CDSNControl);	DoC_Delay(docptr, 4);}

static inline int DoC_WaitReady(unsigned long docptr){	/* This is inline, to optimise the common case, where it's ready instantly */	int ret = 0;	/* read form NOP register should be issued prior to the read from CDSNControl	   see Software Requirement 11.4 item 2. */	DoC_Delay(docptr, 4);	if ((ReadDOC(docptr, Mplus_FlashControl) & CDSN_CTRL_FR_B_MASK) != CDSN_CTRL_FR_B_MASK)		/* Call the out-of-line routine to wait */		ret = _DoC_WaitReady(docptr);	return ret;}

/* DOC_WaitReady: Wait for RDY line to be asserted by the flash chip */static int _DoC_WaitReady(struct DiskOnChip *doc){	void __iomem *docptr = doc->virtadr;	unsigned long timeo = jiffies + (HZ * 10);	pr_debug("_DoC_WaitReady called for out-of-line wait/n");	/* Out-of-line routine to wait for chip response */	while (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B)) {		/* issue 2 read from NOP register after reading from CDSNControl register	   	see Software Requirement 11.4 item 2. */		DoC_Delay(doc, 2);		if (time_after(jiffies, timeo)) {			pr_debug("_DoC_WaitReady timed out./n");			return -EIO;		}		udelay(1);		cond_resched();	}	return 0;}