pmc551.c

老版本的mtd-snap

/*
 * $Id: pmc551.c,v 1.31 2005/03/17 19:44:27 gleixner Exp $
 *
 * 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 it's DRAM banks have 64M
 *	 of ram configured (making a grand total of 256M 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/FIXME's:
 *       * 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/version.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/types.h>
#include <linux/sched.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>

#ifndef CONFIG_PCI
#error Enable PCI in your kernel config
#endif

#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, &ptr);

        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, &ptr);
                }
                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, u_char **mtdbuf)
{
        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;
	}

        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;
	}

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


static void pmc551_unpoint (struct mtd_info *mtd, u_char *addr, 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, &ptr);

        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, &ptr);
                }
                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, &ptr);

        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, &ptr);
                }
                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 );