pmc551.c

基于linux-2.6.28的mtd驱动

/*
 * PMC551 PCI Mezzanine Ram Device
 *
 * Author:
 *	Mark Ferrell <[e-mail]>
 *	Copyright 1999,2000 Nortel Networks
 *
 * License:
 *	As part of this driver was derived from the slram.c driver it
 *	falls under the same license, which is GNU General Public
 *	License v2
 *
 * Description:
 *	This driver is intended to support the PMC551 PCI Ram device
 *	from Ramix Inc.  The PMC551 is a PMC Mezzanine module for
 *	cPCI embedded systems.  The device contains a single SROM
 *	that initially programs the V370PDC chipset onboard the
 *	device, and various banks of DRAM/SDRAM onboard.  This driver
 *	implements this PCI Ram device as an MTD (Memory Technology
 *	Device) so that it can be used to hold a file system, or for
 *	added swap space in embedded systems.  Since the memory on
 *	this board isn't as fast as main memory we do not try to hook
 *	it into main memory as that would simply reduce performance
 *	on the system.  Using it as a block device allows us to use
 *	it as high speed swap or for a high speed disk device of some
 *	sort.  Which becomes very useful on diskless systems in the
 *	embedded market I might add.
 *
 * Notes:
 *	Due to what I assume is more buggy SROM, the 64M PMC551 I
 *	have available claims that all 4 of its DRAM banks have 64MiB
 *	of ram configured (making a grand total of 256MiB onboard).
 *	This is slightly annoying since the BAR0 size reflects the
 *	aperture size, not the dram size, and the V370PDC supplies no
 *	other method for memory size discovery.  This problem is
 *	mostly only relevant when compiled as a module, as the
 *	unloading of the module with an aperture size smaller then
 *	the ram will cause the driver to detect the onboard memory
 *	size to be equal to the aperture size when the module is
 *	reloaded.  Soooo, to help, the module supports an msize
 *	option to allow the specification of the onboard memory, and
 *	an asize option, to allow the specification of the aperture
 *	size.  The aperture must be equal to or less then the memory
 *	size, the driver will correct this if you screw it up.  This
 *	problem is not relevant for compiled in drivers as compiled
 *	in drivers only init once.
 *
 * Credits:
 *	Saeed Karamooz <[e-mail]> of Ramix INC. for the
 *	initial example code of how to initialize this device and for
 *	help with questions I had concerning operation of the device.
 *
 *	Most of the MTD code for this driver was originally written
 *	for the slram.o module in the MTD drivers package which
 *	allows the mapping of system memory into an MTD device.
 *	Since the PMC551 memory module is accessed in the same
 *	fashion as system memory, the slram.c code became a very nice
 *	fit to the needs of this driver.  All we added was PCI
 *	detection/initialization to the driver and automatically figure
 *	out the size via the PCI detection.o, later changes by Corey
 *	Minyard set up the card to utilize a 1M sliding apature.
 *
 *	Corey Minyard <[e-mail]>
 *	* Modified driver to utilize a sliding aperture instead of
 *	 mapping all memory into kernel space which turned out to
 *	 be very wasteful.
 *	* Located a bug in the SROM's initialization sequence that
 *	 made the memory unusable, added a fix to code to touch up
 *	 the DRAM some.
 *
 * Bugs/FIXMEs:
 *	* MUST fix the init function to not spin on a register
 *	waiting for it to set .. this does not safely handle busted
 *	devices that never reset the register correctly which will
 *	cause the system to hang w/ a reboot being the only chance at
 *	recover. [sort of fixed, could be better]
 *	* Add I2C handling of the SROM so we can read the SROM's information
 *	about the aperture size.  This should always accurately reflect the
 *	onboard memory size.
 *	* Comb the init routine.  It's still a bit cludgy on a few things.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <asm/io.h>
#include <asm/system.h>
#include <linux/pci.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/pmc551.h>
#include <linux/mtd/compatmac.h>

static struct mtd_info *pmc551list;

static int pmc551_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	struct mypriv *priv = mtd->priv;
	u32 soff_hi, soff_lo;	/* start address offset hi/lo */
	u32 eoff_hi, eoff_lo;	/* end address offset hi/lo */
	unsigned long end;
	u_char *ptr;
	size_t retlen;

#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_erase(pos:%ld, len:%ld)\n", (long)instr->addr,
		(long)instr->len);
#endif

	end = instr->addr + instr->len - 1;

	/* Is it past the end? */
	if (end > mtd->size) {
#ifdef CONFIG_MTD_PMC551_DEBUG
		printk(KERN_DEBUG "pmc551_erase() out of bounds (%ld > %ld)\n",
			(long)end, (long)mtd->size);
#endif
		return -EINVAL;
	}

	eoff_hi = end & ~(priv->asize - 1);
	soff_hi = instr->addr & ~(priv->asize - 1);
	eoff_lo = end & (priv->asize - 1);
	soff_lo = instr->addr & (priv->asize - 1);

	pmc551_point(mtd, instr->addr, instr->len, &retlen,
		     (void **)&ptr, NULL);

	if (soff_hi == eoff_hi || mtd->size == priv->asize) {
		/* The whole thing fits within one access, so just one shot
		   will do it. */
		memset(ptr, 0xff, instr->len);
	} else {
		/* We have to do multiple writes to get all the data
		   written. */
		while (soff_hi != eoff_hi) {
#ifdef CONFIG_MTD_PMC551_DEBUG
			printk(KERN_DEBUG "pmc551_erase() soff_hi: %ld, "
				"eoff_hi: %ld\n", (long)soff_hi, (long)eoff_hi);
#endif
			memset(ptr, 0xff, priv->asize);
			if (soff_hi + priv->asize >= mtd->size) {
				goto out;
			}
			soff_hi += priv->asize;
			pmc551_point(mtd, (priv->base_map0 | soff_hi),
				     priv->asize, &retlen,
				     (void **)&ptr, NULL);
		}
		memset(ptr, 0xff, eoff_lo);
	}

      out:
	instr->state = MTD_ERASE_DONE;
#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_erase() done\n");
#endif

	mtd_erase_callback(instr);
	return 0;
}

static int pmc551_point(struct mtd_info *mtd, loff_t from, size_t len,
			size_t *retlen, void **virt, resource_size_t *phys)
{
	struct mypriv *priv = mtd->priv;
	u32 soff_hi;
	u32 soff_lo;

#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_point(%ld, %ld)\n", (long)from, (long)len);
#endif

	if (from + len > mtd->size) {
#ifdef CONFIG_MTD_PMC551_DEBUG
		printk(KERN_DEBUG "pmc551_point() out of bounds (%ld > %ld)\n",
			(long)from + len, (long)mtd->size);
#endif
		return -EINVAL;
	}

	/* can we return a physical address with this driver? */
	if (phys)
		return -EINVAL;

	soff_hi = from & ~(priv->asize - 1);
	soff_lo = from & (priv->asize - 1);

	/* Cheap hack optimization */
	if (priv->curr_map0 != from) {
		pci_write_config_dword(priv->dev, PMC551_PCI_MEM_MAP0,
					(priv->base_map0 | soff_hi));
		priv->curr_map0 = soff_hi;
	}

	*virt = priv->start + soff_lo;
	*retlen = len;
	return 0;
}

static void pmc551_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_unpoint()\n");
#endif
}

static int pmc551_read(struct mtd_info *mtd, loff_t from, size_t len,
			size_t * retlen, u_char * buf)
{
	struct mypriv *priv = mtd->priv;
	u32 soff_hi, soff_lo;	/* start address offset hi/lo */
	u32 eoff_hi, eoff_lo;	/* end address offset hi/lo */
	unsigned long end;
	u_char *ptr;
	u_char *copyto = buf;

#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_read(pos:%ld, len:%ld) asize: %ld\n",
		(long)from, (long)len, (long)priv->asize);
#endif

	end = from + len - 1;

	/* Is it past the end? */
	if (end > mtd->size) {
#ifdef CONFIG_MTD_PMC551_DEBUG
		printk(KERN_DEBUG "pmc551_read() out of bounds (%ld > %ld)\n",
			(long)end, (long)mtd->size);
#endif
		return -EINVAL;
	}

	soff_hi = from & ~(priv->asize - 1);
	eoff_hi = end & ~(priv->asize - 1);
	soff_lo = from & (priv->asize - 1);
	eoff_lo = end & (priv->asize - 1);

	pmc551_point(mtd, from, len, retlen, (void **)&ptr, NULL);

	if (soff_hi == eoff_hi) {
		/* The whole thing fits within one access, so just one shot
		   will do it. */
		memcpy(copyto, ptr, len);
		copyto += len;
	} else {
		/* We have to do multiple writes to get all the data
		   written. */
		while (soff_hi != eoff_hi) {
#ifdef CONFIG_MTD_PMC551_DEBUG
			printk(KERN_DEBUG "pmc551_read() soff_hi: %ld, "
				"eoff_hi: %ld\n", (long)soff_hi, (long)eoff_hi);
#endif
			memcpy(copyto, ptr, priv->asize);
			copyto += priv->asize;
			if (soff_hi + priv->asize >= mtd->size) {
				goto out;
			}
			soff_hi += priv->asize;
			pmc551_point(mtd, soff_hi, priv->asize, retlen,
				     (void **)&ptr, NULL);
		}
		memcpy(copyto, ptr, eoff_lo);
		copyto += eoff_lo;
	}

      out:
#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_read() done\n");
#endif
	*retlen = copyto - buf;
	return 0;
}

static int pmc551_write(struct mtd_info *mtd, loff_t to, size_t len,
			size_t * retlen, const u_char * buf)
{
	struct mypriv *priv = mtd->priv;
	u32 soff_hi, soff_lo;	/* start address offset hi/lo */
	u32 eoff_hi, eoff_lo;	/* end address offset hi/lo */
	unsigned long end;
	u_char *ptr;
	const u_char *copyfrom = buf;

#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_write(pos:%ld, len:%ld) asize:%ld\n",
		(long)to, (long)len, (long)priv->asize);
#endif

	end = to + len - 1;
	/* Is it past the end?  or did the u32 wrap? */
	if (end > mtd->size) {
#ifdef CONFIG_MTD_PMC551_DEBUG
		printk(KERN_DEBUG "pmc551_write() out of bounds (end: %ld, "
			"size: %ld, to: %ld)\n", (long)end, (long)mtd->size,
			(long)to);
#endif
		return -EINVAL;
	}

	soff_hi = to & ~(priv->asize - 1);
	eoff_hi = end & ~(priv->asize - 1);
	soff_lo = to & (priv->asize - 1);
	eoff_lo = end & (priv->asize - 1);

	pmc551_point(mtd, to, len, retlen, (void **)&ptr, NULL);

	if (soff_hi == eoff_hi) {
		/* The whole thing fits within one access, so just one shot
		   will do it. */
		memcpy(ptr, copyfrom, len);
		copyfrom += len;
	} else {
		/* We have to do multiple writes to get all the data
		   written. */
		while (soff_hi != eoff_hi) {
#ifdef CONFIG_MTD_PMC551_DEBUG
			printk(KERN_DEBUG "pmc551_write() soff_hi: %ld, "
				"eoff_hi: %ld\n", (long)soff_hi, (long)eoff_hi);
#endif
			memcpy(ptr, copyfrom, priv->asize);
			copyfrom += priv->asize;
			if (soff_hi >= mtd->size) {
				goto out;
			}
			soff_hi += priv->asize;
			pmc551_point(mtd, soff_hi, priv->asize, retlen,
				     (void **)&ptr, NULL);
		}
		memcpy(ptr, copyfrom, eoff_lo);
		copyfrom += eoff_lo;
	}

      out:
#ifdef CONFIG_MTD_PMC551_DEBUG
	printk(KERN_DEBUG "pmc551_write() done\n");
#endif
	*retlen = copyfrom - buf;
	return 0;
}

/*
 * Fixup routines for the V370PDC
 * PCI device ID 0x020011b0
 *
 * This function basicly kick starts the DRAM oboard the card and gets it
 * ready to be used.  Before this is done the device reads VERY erratic, so
 * much that it can crash the Linux 2.2.x series kernels when a user cat's
 * /proc/pci .. though that is mainly a kernel bug in handling the PCI DEVSEL
 * register.  FIXME: stop spinning on registers .. must implement a timeout
 * mechanism
 * returns the size of the memory region found.
 */
static u32 fixup_pmc551(struct pci_dev *dev)
{
#ifdef CONFIG_MTD_PMC551_BUGFIX
	u32 dram_data;
#endif
	u32 size, dcmd, cfg, dtmp;
	u16 cmd, tmp, i;
	u8 bcmd, counter;

	/* Sanity Check */
	if (!dev) {
		return -ENODEV;
	}

	/*
	 * Attempt to reset the card
	 * FIXME: Stop Spinning registers
	 */
	counter = 0;
	/* unlock registers */
	pci_write_config_byte(dev, PMC551_SYS_CTRL_REG, 0xA5);
	/* read in old data */
	pci_read_config_byte(dev, PMC551_SYS_CTRL_REG, &bcmd);
	/* bang the reset line up and down for a few */
	for (i = 0; i < 10; i++) {
		counter = 0;
		bcmd &= ~0x80;
		while (counter++ < 100) {
			pci_write_config_byte(dev, PMC551_SYS_CTRL_REG, bcmd);
		}
		counter = 0;
		bcmd |= 0x80;
		while (counter++ < 100) {
			pci_write_config_byte(dev, PMC551_SYS_CTRL_REG, bcmd);
		}
	}
	bcmd |= (0x40 | 0x20);
	pci_write_config_byte(dev, PMC551_SYS_CTRL_REG, bcmd);

	/*
	 * Take care and turn off the memory on the device while we
	 * tweak the configurations
	 */
	pci_read_config_word(dev, PCI_COMMAND, &cmd);
	tmp = cmd & ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY);
	pci_write_config_word(dev, PCI_COMMAND, tmp);

	/*
	 * Disable existing aperture before probing memory size
	 */
	pci_read_config_dword(dev, PMC551_PCI_MEM_MAP0, &dcmd);
	dtmp = (dcmd | PMC551_PCI_MEM_MAP_ENABLE | PMC551_PCI_MEM_MAP_REG_EN);
	pci_write_config_dword(dev, PMC551_PCI_MEM_MAP0, dtmp);
	/*
	 * Grab old BAR0 config so that we can figure out memory size
	 * This is another bit of kludge going on.  The reason for the
	 * redundancy is I am hoping to retain the original configuration
	 * previously assigned to the card by the BIOS or some previous
	 * fixup routine in the kernel.  So we read the old config into cfg,
	 * then write all 1's to the memory space, read back the result into
	 * "size", and then write back all the old config.
	 */
	pci_read_config_dword(dev, PCI_BASE_ADDRESS_0, &cfg);
#ifndef CONFIG_MTD_PMC551_BUGFIX
	pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, ~0);
	pci_read_config_dword(dev, PCI_BASE_ADDRESS_0, &size);
	size = (size & PCI_BASE_ADDRESS_MEM_MASK);
	size &= ~(size - 1);
	pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, cfg);
#else
	/*
	 * Get the size of the memory by reading all the DRAM size values
	 * and adding them up.