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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>Init function</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="MTD NAND Driver Programming Interface" /><link rel="up" href="ch04.html" title="Chapter 4. Basic board driver" /><link rel="prev" href="ch04s04.html" title="Device ready function" /><link rel="next" href="ch04s06.html" title="Exit function" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Init function</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04s04.html">Prev</a> </td><th width="60%" align="center">Chapter 4. Basic board driver</th><td width="20%" align="right"> <a accesskey="n" href="ch04s06.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="Init function"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Init_function"></a>Init function</h2></div></div></div><p>
The init function allocates memory and sets up all the board
specific parameters and function pointers. When everything
is set up nand_scan() is called. This function tries to
detect and identify then chip. If a chip is found all the
internal data fields are initialized accordingly.
The structure(s) have to be zeroed out first and then filled with the neccecary
information about the device.
</p><pre class="programlisting">
int __init board_init (void)
{
struct nand_chip *this;
int err = 0;
/* Allocate memory for MTD device structure and private data */
board_mtd = kzalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip), GFP_KERNEL);
if (!board_mtd) {
printk ("Unable to allocate NAND MTD device structure.\n");
err = -ENOMEM;
goto out;
}
/* map physical address */
baseaddr = (unsigned long)ioremap(CHIP_PHYSICAL_ADDRESS, 1024);
if(!baseaddr){
printk("Ioremap to access NAND chip failed\n");
err = -EIO;
goto out_mtd;
}
/* Get pointer to private data */
this = (struct nand_chip *) ();
/* Link the private data with the MTD structure */
board_mtd->priv = this;
/* Set address of NAND IO lines */
this->IO_ADDR_R = baseaddr;
this->IO_ADDR_W = baseaddr;
/* Reference hardware control function */
this->hwcontrol = board_hwcontrol;
/* Set command delay time, see datasheet for correct value */
this->chip_delay = CHIP_DEPENDEND_COMMAND_DELAY;
/* Assign the device ready function, if available */
this->dev_ready = board_dev_ready;
this->eccmode = NAND_ECC_SOFT;
/* Scan to find existence of the device */
if (nand_scan (board_mtd, 1)) {
err = -ENXIO;
goto out_ior;
}
add_mtd_partitions(board_mtd, partition_info, NUM_PARTITIONS);
goto out;
out_ior:
iounmap((void *)baseaddr);
out_mtd:
kfree (board_mtd);
out:
return err;
}
module_init(board_init);
</pre></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch04s04.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch04.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch04s06.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Device ready function </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Exit function</td></tr></table></div></body></html>
