pmc551.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 * $Id: pmc551.c,v 1.11 2000/11/23 13:40:12 dwmw2 Exp $
 *
 * PMC551 PCI Mezzanine Ram Device
 *
 * Author:
 *       Mark Ferrell <[e-mail]>
 *       Copyright 1999,2000 Nortel Networks
 *
 * License:
 *	 As part of this driver was derrived 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 embeded
 *	 systems.  The device contains a single SROM that initally 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
 *	 Technologies Device) so that it can be used to hold a filesystem, or
 *	 for added swap space in embeded systems.  Since the memory on this
 *	 board isn't as fast as main memory we do not try to hook it into main
 *	 memeory 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 usefull on
 *	 diskless systems in the embeded 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 relivant 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 relivant 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 written by David Hinds
 *       <[e-mail]> 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 automaticly figure out
 *       the size via the PCI detection.o, later changes by Corey Minyard
 *       settup the card to utilize a 1M sliding apature.
 *
 *	 Corey Minyard <[e-mail]>
 *       * Modified driver to utilize a sliding apature instead of mapping all
 *       memory into kernel space which turned out to be very wastefull.
 *       * 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 beeing the only chance at recover.
 */

#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/malloc.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 <asm/segment.h>
#include <stdarg.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>

#if LINUX_VERSION_CODE > 0x20300
#define PCI_BASE_ADDRESS(dev) (dev->resource[0].start)
#else
#define PCI_BASE_ADDRESS(dev) (dev->base_address[0])
#endif

static struct mtd_info *pmc551list = NULL;

static int pmc551_erase (struct mtd_info *mtd, struct erase_info *instr)
{
        struct mypriv *priv = mtd->priv;
        u32 start_addr_highbits;
        u32 end_addr_highbits;
        u32 start_addr_lowbits;
        u32 end_addr_lowbits;
        unsigned long end;

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

        /* Is it too much memory?  The second check find if we wrap around
           past the end of a u32. */
        if ((end > mtd->size) || (end < instr->addr)) {
                return -EINVAL;
        }

        start_addr_highbits = instr->addr & PMC551_ADDR_HIGH_MASK;
        end_addr_highbits = end & PMC551_ADDR_HIGH_MASK;
        start_addr_lowbits = instr->addr & PMC551_ADDR_LOW_MASK;
        end_addr_lowbits = end & PMC551_ADDR_LOW_MASK;

        pci_write_config_dword ( priv->dev,
                                 PMC551_PCI_MEM_MAP0,
                                 (priv->mem_map0_base_val
                                  | start_addr_highbits));
        if (start_addr_highbits == end_addr_highbits) {
                /* The whole thing fits within one access, so just one shot
                   will do it. */
                memset(priv->start + start_addr_lowbits,
                       0xff,
                       instr->len);
        } else {
                /* We have to do multiple writes to get all the data
                   written. */
                memset(priv->start + start_addr_lowbits,
                       0xff,
                       priv->aperture_size - start_addr_lowbits);
                start_addr_highbits += priv->aperture_size;
                while (start_addr_highbits != end_addr_highbits) {
                        pci_write_config_dword ( priv->dev,
                                                 PMC551_PCI_MEM_MAP0,
                                                 (priv->mem_map0_base_val
                                                  | start_addr_highbits));
                        memset(priv->start,
                               0xff,
                               priv->aperture_size);
                        start_addr_highbits += priv->aperture_size;
                }
                priv->curr_mem_map0_val = (priv->mem_map0_base_val
                                           | start_addr_highbits);
                pci_write_config_dword ( priv->dev,
                                         PMC551_PCI_MEM_MAP0,
                                         priv->curr_mem_map0_val);
                memset(priv->start,
                       0xff,
                       end_addr_lowbits);
        }

	instr->state = MTD_ERASE_DONE;

        if (instr->callback) {
                (*(instr->callback))(instr);
	}

        return 0;
}


static void pmc551_unpoint (struct mtd_info *mtd, u_char *addr)
{}


static int pmc551_read (struct mtd_info *mtd,
                        loff_t from,
                        size_t len,
                        size_t *retlen,
                        u_char *buf)
{
        struct mypriv *priv = (struct mypriv *)mtd->priv;
        u32 start_addr_highbits;
        u32 end_addr_highbits;
        u32 start_addr_lowbits;
        u32 end_addr_lowbits;
        unsigned long end;
        u_char *copyto = buf;


        /* Is it past the end? */
        if (from > mtd->size) {
                return -EINVAL;
        }

        end = from + len;
        start_addr_highbits = from & PMC551_ADDR_HIGH_MASK;
        end_addr_highbits = end & PMC551_ADDR_HIGH_MASK;
        start_addr_lowbits = from & PMC551_ADDR_LOW_MASK;
        end_addr_lowbits = end & PMC551_ADDR_LOW_MASK;


        /* Only rewrite the first value if it doesn't match our current
           values.  Most operations are on the same page as the previous
           value, so this is a pretty good optimization. */
        if (priv->curr_mem_map0_val !=
                        (priv->mem_map0_base_val | start_addr_highbits)) {
                priv->curr_mem_map0_val = (priv->mem_map0_base_val
                                           | start_addr_highbits);
                pci_write_config_dword ( priv->dev,
                                         PMC551_PCI_MEM_MAP0,
                                         priv->curr_mem_map0_val);
        }

        if (start_addr_highbits == end_addr_highbits) {
                /* The whole thing fits within one access, so just one shot
                   will do it. */
                memcpy(copyto,
                       priv->start + start_addr_lowbits,
                       len);
                copyto += len;
        } else {
                /* We have to do multiple writes to get all the data
                   written. */
                memcpy(copyto,
                       priv->start + start_addr_lowbits,
                       priv->aperture_size - start_addr_lowbits);
                copyto += priv->aperture_size - start_addr_lowbits;
                start_addr_highbits += priv->aperture_size;
                while (start_addr_highbits != end_addr_highbits) {
                        pci_write_config_dword ( priv->dev,
                                                 PMC551_PCI_MEM_MAP0,
                                                 (priv->mem_map0_base_val
                                                  | start_addr_highbits));
                        memcpy(copyto,
                               priv->start,
                               priv->aperture_size);
                        copyto += priv->aperture_size;
                        start_addr_highbits += priv->aperture_size;
                        if (start_addr_highbits >= mtd->size) {
                                /* Make sure we have the right value here. */
                                priv->curr_mem_map0_val
                                = (priv->mem_map0_base_val
                                   | start_addr_highbits);
                                goto out;
                        }
                }
                priv->curr_mem_map0_val = (priv->mem_map0_base_val
                                           | start_addr_highbits);
                pci_write_config_dword ( priv->dev,
                                         PMC551_PCI_MEM_MAP0,
                                         priv->curr_mem_map0_val);
                memcpy(copyto,
                       priv->start,
                       end_addr_lowbits);
                copyto += end_addr_lowbits;
        }

out:
        *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 = (struct mypriv *)mtd->priv;
        u32 start_addr_highbits;
        u32 end_addr_highbits;
        u32 start_addr_lowbits;
        u32 end_addr_lowbits;
        unsigned long end;
        const u_char *copyfrom = buf;


        /* Is it past the end? */
        if (to > mtd->size) {
                return -EINVAL;
        }

        end = to + len;
        start_addr_highbits = to & PMC551_ADDR_HIGH_MASK;
        end_addr_highbits = end & PMC551_ADDR_HIGH_MASK;