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下面列出的几段代码是dm9000驱动程序对一些常用的读写操作的封装，比如寄存器读写，IO内存块读写，eeprom读写，phy寄存器读写等等/* routines for sending block to chip */
static void dm9000_outblk_8bit(void __iomem *reg, void *data, int count)
{iowrite8_rep(reg, data, count);
}static void dm9000_outblk_16bit(void __iomem *reg, void *data, int count)
{iowrite16_rep(reg, data, (count+1) >> 1);
}static void dm9000_outblk_32bit(void __iomem *reg, void *data, int count)
{iowrite32_rep(reg, data, (count+3) >> 2);
}/* input block from chip to memory */static void dm9000_inblk_8bit(void __iomem *reg, void *data, int count)
{ioread8_rep(reg, data, count);
}static void dm9000_inblk_16bit(void __iomem *reg, void *data, int count)
{ioread16_rep(reg, data, (count+1) >> 1);
}static void dm9000_inblk_32bit(void __iomem *reg, void *data, int count)
{ioread32_rep(reg, data, (count+3) >> 2);
}/* dump block from chip to null */static void dm9000_dumpblk_8bit(void __iomem *reg, int count)
{int i;int tmp;for (i = 0; i < count; i++)tmp = readb(reg);
}static void dm9000_dumpblk_16bit(void __iomem *reg, int count)
{int i;int tmp;count = (count + 1) >> 1;for (i = 0; i < count; i++)tmp = readw(reg);
}static void dm9000_dumpblk_32bit(void __iomem *reg, int count)
{int i;int tmp;count = (count + 3) >> 2;for (i = 0; i < count; i++)tmp = readl(reg);
}/* dm9000_set_io** select the specified set of io routines to use with the* device*/
static void dm9000_set_io(struct board_info *db, int byte_width)
{/* use the size of the data resource to work out what IO* routines we want to use*/switch (byte_width) {case 1:db->dumpblk = dm9000_dumpblk_8bit;db->outblk = dm9000_outblk_8bit;db->inblk = dm9000_inblk_8bit;break;case 3:dev_dbg(db->dev, ": 3 byte IO, falling back to 16bit\n");case 2:db->dumpblk = dm9000_dumpblk_16bit;db->outblk = dm9000_outblk_16bit;db->inblk = dm9000_inblk_16bit;break;case 4:default:db->dumpblk = dm9000_dumpblk_32bit;db->outblk = dm9000_outblk_32bit;db->inblk = dm9000_inblk_32bit;break;}
}/** Read a byte from I/O port*/
static u8 ior(struct board_info *db, int reg)
{writeb(reg, db->io_addr);return readb(db->io_data);
}/** Write a byte to I/O port*/
static void iow(struct board_info *db, int reg, int value)
{writeb(reg, db->io_addr);writeb(value, db->io_data);
}看到代码可以知道，对寄存器的读写分两个步骤，要对寄存器reg读或者写
首先把reg的值写入io_addr, 然后再对io_data进行读写操作
可以理解为我们要读写某些值，首先把存储这些值的地址赋值给io_addr， 接下来读写io_data
static int dm9000_wait_eeprom(struct board_info *db)
{unsigned int status;int timeout = 8; /* wait max 8msec *//* The DM9000 data sheets say we should be able to* poll the ERRE bit in EPCR to wait for the EEPROM* operation. From testing several chips, this bit* does not seem to work.** We attempt to use the bit, but fall back to the* timeout (which is why we do not return an error* on expiry) to say that the EEPROM operation has* completed.*/while (1) {status = dm9000_read_locked(db, DM9000_EPCR);if ((status & EPCR_ERRE) == 0)break;msleep(1);if (timeout-- < 0) {dev_dbg(db->dev, "timeout waiting EEPROM\n");break;}}return 0;
}/** Read a word data from EEPROM*/
static void
dm9000_read_eeprom(struct board_info *db, int offset, u8 *to)
{unsigned long flags;if (db->flags & DM9000_PLATF_NO_EEPROM) {to[0] = 0xff;to[1] = 0xff;return;}mutex_lock(&db->addr_lock);spin_lock_irqsave(&db->lock, flags);iow(db, DM9000_EPAR, offset);iow(db, DM9000_EPCR, EPCR_ERPRR);spin_unlock_irqrestore(&db->lock, flags);dm9000_wait_eeprom(db);/* delay for at-least 150uS */msleep(1);spin_lock_irqsave(&db->lock, flags);iow(db, DM9000_EPCR, 0x0);to[0] = ior(db, DM9000_EPDRL);to[1] = ior(db, DM9000_EPDRH);spin_unlock_irqrestore(&db->lock, flags);mutex_unlock(&db->addr_lock);
}/** Write a word data to SROM*/
static void
dm9000_write_eeprom(struct board_info *db, int offset, u8 *data)
{unsigned long flags;if (db->flags & DM9000_PLATF_NO_EEPROM)return;mutex_lock(&db->addr_lock);spin_lock_irqsave(&db->lock, flags);iow(db, DM9000_EPAR, offset);iow(db, DM9000_EPDRH, data[1]);iow(db, DM9000_EPDRL, data[0]);iow(db, DM9000_EPCR, EPCR_WEP | EPCR_ERPRW);spin_unlock_irqrestore(&db->lock, flags);dm9000_wait_eeprom(db);mdelay(1); /* wait at least 150uS to clear */spin_lock_irqsave(&db->lock, flags);iow(db, DM9000_EPCR, 0);spin_unlock_irqrestore(&db->lock, flags);mutex_unlock(&db->addr_lock);
}对eeprom的读写，一系列的读写寄存器操作
/** Sleep, either by using msleep() or if we are suspending, then* use mdelay() to sleep.*/
static void dm9000_msleep(struct board_info *db, unsigned int ms)
{if (db->in_suspend || db->in_timeout)mdelay(ms);elsemsleep(ms);
}/* Read a word from phyxcer */
static int dm9000_phy_read(struct net_device *dev, int phy_reg_unused, int reg)
{struct board_info *db = netdev_priv(dev);unsigned long flags;unsigned int reg_save;int ret;mutex_lock(&db->addr_lock);spin_lock_irqsave(&db->lock, flags);/* Save previous register address */reg_save = readb(db->io_addr);/* Fill the phyxcer register into REG_0C */iow(db, DM9000_EPAR, DM9000_PHY | reg);/* Issue phyxcer read command */iow(db, DM9000_EPCR, EPCR_ERPRR | EPCR_EPOS);writeb(reg_save, db->io_addr);spin_unlock_irqrestore(&db->lock, flags);dm9000_msleep(db, 1); /* Wait read complete */spin_lock_irqsave(&db->lock, flags);reg_save = readb(db->io_addr);iow(db, DM9000_EPCR, 0x0); /* Clear phyxcer read command *//* The read data keeps on REG_0D & REG_0E */ret = (ior(db, DM9000_EPDRH) << 8) | ior(db, DM9000_EPDRL);/* restore the previous address */writeb(reg_save, db->io_addr);spin_unlock_irqrestore(&db->lock, flags);mutex_unlock(&db->addr_lock);dm9000_dbg(db, 5, "phy_read[%02x] -> %04x\n", reg, ret);return ret;
}/* Write a word to phyxcer */
static void dm9000_phy_write(struct net_device *dev,int phyaddr_unused, int reg, int value)
{struct board_info *db = netdev_priv(dev);unsigned long flags;unsigned long reg_save;dm9000_dbg(db, 5, "phy_write[%02x] = %04x\n", reg, value);if (!db->in_timeout)mutex_lock(&db->addr_lock);spin_lock_irqsave(&db->lock, flags);/* Save previous register address */reg_save = readb(db->io_addr);/* Fill the phyxcer register into REG_0C */iow(db, DM9000_EPAR, DM9000_PHY | reg);/* Fill the written data into REG_0D & REG_0E */iow(db, DM9000_EPDRL, value);iow(db, DM9000_EPDRH, value >> 8);/* Issue phyxcer write command */iow(db, DM9000_EPCR, EPCR_EPOS | EPCR_ERPRW);writeb(reg_save, db->io_addr);spin_unlock_irqrestore(&db->lock, flags);dm9000_msleep(db, 1); /* Wait write complete */spin_lock_irqsave(&db->lock, flags);reg_save = readb(db->io_addr);iow(db, DM9000_EPCR, 0x0); /* Clear phyxcer write command *//* restore the previous address */writeb(reg_save, db->io_addr);spin_unlock_irqrestore(&db->lock, flags);if (!db->in_timeout)mutex_unlock(&db->addr_lock);
}这篇关于DM9000网卡驱动源码分析系列02 - 读写的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
