+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ * for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/pagemap.h>
+#include <linux/mtd/mtd.h>
+#include <linux/interrupt.h>
+#include <linux/string.h>
+#include <linux/locks.h>
+
+#include <asm/uaccess.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+
+#define T(x) printk x
+#define ALLOCATE(x) kmalloc(x,GFP_KERNEL)
+#define FREE(x) kfree(x)
+
+#define DEFAULT_SIZE_IN_MB 16
+
+#define NAND_SHIFT 9
+
+
+static struct mtd_info nandemul_mtd;
+
+typedef struct
+{
+ __u8 data[528]; // Data + spare
+ int count[3]; // The programming count for each area of
+ // the page (0..255,256..511,512..527
+ int empty; // is this empty?
+} nandemul_Page;
+
+typedef struct
+{
+ nandemul_Page page[32]; // The pages in the block
+ __u8 damaged; // Is the block damaged?
+
+} nandemul_Block;
+
+
+
+typedef struct
+{
+ nandemul_Block **block;
+ int nBlocks;
+} nandemul_Device;
+
+nandemul_Device device;
+
+int sizeInMB = DEFAULT_SIZE_IN_MB;
+
+int nandemul_CalcNBlocks(void)
+{
+ switch(sizeInMB)
+ {
+ case 8:
+ case 16:
+ case 32:
+ case 64:
+ case 128:
+ case 256:
+ case 512:
+ break;
+ default:
+ sizeInMB = DEFAULT_SIZE_IN_MB;
+ }
+ return sizeInMB * 64;
+}
+
+
+static void nandemul_ReallyEraseBlock(int blockNumber)
+{
+ int i;
+
+ nandemul_Block *theBlock = device.block[blockNumber];
+
+ for(i = 0; i < 32; i++)
+ {
+ memset(theBlock->page[i].data,0xff,528);
+ theBlock->page[i].count[0] = 0;
+ theBlock->page[i].count[1] = 0;
+ theBlock->page[i].count[2] = 0;
+ theBlock->page[i].empty = 1;
+ }
+
+}
+
+static int nandemul_DoErase(int blockNumber)
+{
+ if(blockNumber < 0 || nandemul_CalcNBlocks())
+ {
+ T(("Attempt to erase non-existant block %d\n",blockNumber));
+ }
+ else if(device.block[blockNumber]->damaged)
+ {
+ T(("Attempt to erase damaged block %d\n",blockNumber));
+ }
+ else
+ {
+ nandemul_ReallyEraseBlock(blockNumber);
+ }
+
+ return 1;
+
+}
+
+
+int nandemul_Initialise(void)
+{
+ int i;
+ int fail = 0;
+ int nBlocks = nandemul_CalcNBlocks();
+ int nAllocated = 0;
+
+ device.block = ALLOCATE (sizeof(nandemul_Block *) * nBlocks);
+
+ if(!device.block) return 0;
+
+ for(i=0; i <nBlocks; i++)
+ {
+ device.block[i] = NULL;
+ }
+
+ for(i=0; i <nBlocks && !fail; i++)
+ {
+ if((device.block[i] = ALLOCATE(sizeof(nandemul_Block))) == 0)
+ {
+ fail = 1;
+ }
+ else
+ {
+ nandemul_ReallyEraseBlock(i);
+ device.block[i]->damaged = 0;
+ nAllocated++;
+ }
+ }
+
+ if(fail)
+ {
+ for(i = 0; i < nAllocated; i++)
+ {
+ FREE(device.block[i]);
+ }
+ FREE(device.block);
+
+ T(("Allocation failed, could only allocate %dMB of %dMB requested.\n",
+ nAllocated/64,sizeInMB));
+ return 0;
+ }
+
+ device.nBlocks = nBlocks;
+ return 1;
+}
+
+int nandemul_DeInitialise(void)
+{
+ int i;
+ for(i = 0; i < device.nBlocks; i++)
+ {
+ FREE(device.block[i]);
+ device.block[i] = NULL;
+ }
+
+ FREE(device.block);
+ device.block = NULL;
+ return 1;
+}
+
+int nandemul_GetNumberOfBlocks(__u32 *nBlocks)
+{
+ *nBlocks = device.nBlocks;
+
+ return 1;
+}
+
+int nandemul_Reset(void)
+{
+ // Do nothing
+ return 1;
+}
+
+int nandemul_Read(__u8 *buffer, __u32 pageAddress,__u32 pageOffset, __u32 nBytes)
+{
+ unsigned blockN, pageN;
+
+ blockN = pageAddress/32;
+ pageN = pageAddress % 32;
+
+ // TODO: Do tests for valid blockN, pageN, pageOffset
+
+ memcpy(buffer,&device.block[blockN]->page[pageN].data[pageOffset],nBytes);
+
+ return 1;
+
+}
+
+int nandemul_Program(const __u8 *buffer, __u32 pageAddress,__u32 pageOffset, __u32 nBytes)
+{
+ unsigned blockN, pageN, pageO;
+
+ int p0, p1, p2;
+ int i;
+
+ blockN = pageAddress/32;
+ pageN = pageAddress % 32;
+ p0 = 0;
+ p1 = 0;
+ p2 = 0;
+
+ // TODO: Do tests for valid blockN, pageN, pageOffset
+
+
+ for(i = 0,pageO = pageOffset; i < nBytes; i++, pageO++)
+ {
+ device.block[blockN]->page[pageN].data[pageO] &= buffer[i];
+
+ if(pageO < 256) p0 = 1;
+ else if(pageO <512) p1 = 1;
+ else p2 = 1;
+ }
+
+ device.block[blockN]->page[pageN].empty = 0;
+ device.block[blockN]->page[pageN].count[0] += p0;
+ device.block[blockN]->page[pageN].count[1] += p1;
+ device.block[blockN]->page[pageN].count[2] += p2;
+
+ if(device.block[blockN]->page[pageN].count[0] > 1)
+ {
+ T(("block %d page %d first half programmed %d times\n",
+ blockN,pageN,device.block[blockN]->page[pageN].count[0]));
+ }
+ if(device.block[blockN]->page[pageN].count[1] > 1)
+ {
+ T(("block %d page %d second half programmed %d times\n",
+ blockN,pageN,device.block[blockN]->page[pageN].count[1]));
+ }
+ if(device.block[blockN]->page[pageN].count[2] > 3)
+ {
+ T(("block %d page %d spare programmed %d times\n",
+ blockN,pageN,device.block[blockN]->page[pageN].count[2]));
+ }
+
+ return 1;
+
+}
+
+int nandemul_CauseBitErrors( __u32 pageAddress, __u32 pageOffset, __u8 xorPattern)
+{
+ unsigned blockN, pageN;
+
+
+ blockN = pageAddress/32;
+ pageN = pageAddress % 32;
+
+
+ // TODO: Do tests for valid blockN, pageN, pageOffset
+
+ device.block[blockN]->page[pageN].data[pageOffset] ^= xorPattern;
+
+
+ return 1;
+
+}
+
+
+int nandemul_BlockErase(__u32 pageAddress)
+{
+ unsigned blockN;
+
+ blockN = pageAddress/32;
+
+ // TODO: Do tests for valid blockN
+ // TODO: Test that the block has not failed
+
+ return nandemul_DoErase(blockN);
+
+}
+
+int nandemul_FailBlock(__u32 pageAddress)
+{
+ unsigned blockN;
+
+ blockN = pageAddress/32;
+
+ // TODO: Do tests for valid blockN
+ // TODO: Test that the block has not failed
+
+ nandemul_DoErase(blockN);
+ return 1;
+}
+
+int nandemul_ReadId(__u8 *vendorId, __u8 *deviceId)
+{
+ *vendorId = 0xEC;
+ *deviceId = 0x75;
+
+ return 1;
+}
+
+int nandemul_CopyPage(__u32 fromPageAddress, __u32 toPageAddress)
+{
+ __u8 copyBuffer[528];
+
+ // TODO: Check the bitplane issue.
+ nandemul_Read(copyBuffer, fromPageAddress,0,528);
+ nandemul_Program(copyBuffer, toPageAddress,0,528);
+
+ return 1;
+}
+
+int nandemul_ReadStatus(__u8 *status)
+{
+ *status = 0;
+ return 1;
+}
+
+
+#ifdef CONFIG_MTD_NAND_ECC
+#include <linux/mtd/nand_ecc.h>
+#endif
+
+/*
+ * NAND low-level MTD interface functions
+ */
+static int nand_read (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf);
+static int nand_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf, u_char *ecc_code);
+static int nand_read_oob (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf);
+static int nand_write (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf);
+static int nand_write_ecc (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf,
+ u_char *ecc_code);
+static int nand_write_oob (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf);
+static int nand_writev (struct mtd_info *mtd, const struct iovec *vecs,
+ unsigned long count, loff_t to, size_t *retlen);
+static int nand_erase (struct mtd_info *mtd, struct erase_info *instr);
+static void nand_sync (struct mtd_info *mtd);
+
+
+
+/*
+ * NAND read
+ */
+static int nand_read (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ return nand_read_ecc (mtd, from, len, retlen, buf, NULL);
+}
+
+/*
+ * NAND read with ECC
+ */
+static int nand_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf, u_char *ecc_code)
+{
+ int start, page;
+ int n = len;
+ int nToCopy;
+
+
+
+ /* Do not allow reads past end of device */
+ if ((from + len) > mtd->size) {
+ *retlen = 0;
+ return -EINVAL;
+ }
+
+
+ /* Initialize return value */
+ *retlen = 0;
+
+ while(n > 0)
+ {
+
+ /* First we calculate the starting page */
+ page = from >> NAND_SHIFT;
+
+ /* Get raw starting column */
+
+ start = from & (mtd->oobblock-1);
+
+ // OK now check for the curveball where the start and end are in
+ // the same page
+ if((start + n) < mtd->oobblock)
+ {
+ nToCopy = n;
+ }
+ else
+ {
+ nToCopy = mtd->oobblock - start;
+ }
+
+ nandemul_Read(buf, page, start, nToCopy);
+
+ n -= nToCopy;
+ from += nToCopy;
+ buf += nToCopy;
+ *retlen += nToCopy;
+
+ }
+
+
+ return 0;
+}
+
+/*
+ * NAND read out-of-band
+ */
+static int nand_read_oob (struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ int col, page;
+
+ DEBUG (MTD_DEBUG_LEVEL3,
+ "nand_read_oob: from = 0x%08x, len = %i\n", (unsigned int) from,
+ (int) len);
+
+ /* Shift to get page */
+ page = ((int) from) >> NAND_SHIFT;
+
+ /* Mask to get column */
+ col = from & 0x0f;
+
+ /* Initialize return length value */
+ *retlen = 0;
+
+ /* Do not allow reads past end of device */
+ if ((from + len) > mtd->size) {
+ DEBUG (MTD_DEBUG_LEVEL0,
+ "nand_read_oob: Attempt read beyond end of device\n");
+ *retlen = 0;
+ return -EINVAL;
+ }
+
+ nandemul_Read(buf,page,512 + col,len);
+
+ /* Return happy */
+ *retlen = len;
+ return 0;
+}
+
+/*
+ * NAND write
+ */
+static int nand_write (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ return nand_write_ecc (mtd, to, len, retlen, buf, NULL);
+}
+
+/*
+ * NAND write with ECC
+ */
+static int nand_write_ecc (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf,
+ u_char *ecc_code)
+{
+
+ int start, page;
+ int n = len;
+ int nToCopy;
+
+
+
+ /* Do not allow reads past end of device */
+ if ((to + len) > mtd->size) {
+ *retlen = 0;
+ return -EINVAL;
+ }
+
+
+ /* Initialize return value */
+ *retlen = 0;
+
+ while(n > 0)
+ {
+
+ /* First we calculate the starting page */
+ page = to >> NAND_SHIFT;
+
+ /* Get raw starting column */
+
+ start = to & (mtd->oobblock - 1);
+
+ // OK now check for the curveball where the start and end are in
+ // the same page
+ if((start + n) < mtd->oobblock)
+ {
+ nToCopy = n;
+ }
+ else
+ {
+ nToCopy = mtd->oobblock - start;
+ }
+
+ nandemul_Program(buf, page, start, nToCopy);
+
+ n -= nToCopy;
+ to += nToCopy;
+ buf += nToCopy;
+ *retlen += nToCopy;
+
+ }
+
+
+ return 0;
+}
+
+/*
+ * NAND write out-of-band
+ */
+static int nand_write_oob (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ int col, page;
+
+
+ DEBUG (MTD_DEBUG_LEVEL3,
+ "nand_read_oob: to = 0x%08x, len = %i\n", (unsigned int) to,
+ (int) len);
+
+ /* Shift to get page */
+ page = ((int) to) >> NAND_SHIFT;
+
+ /* Mask to get column */
+ col = to & 0x0f;
+
+ /* Initialize return length value */
+ *retlen = 0;
+
+ /* Do not allow reads past end of device */
+ if ((to + len) > mtd->size) {
+ DEBUG (MTD_DEBUG_LEVEL0,
+ "nand_read_oob: Attempt read beyond end of device\n");
+ *retlen = 0;
+ return -EINVAL;
+ }
+
+ nandemul_Program(buf,page,512 + col,len);
+
+ /* Return happy */
+ *retlen = len;
+ return 0;
+
+}
+
+/*
+ * NAND write with iovec
+ */
+static int nand_writev (struct mtd_info *mtd, const struct iovec *vecs,
+ unsigned long count, loff_t to, size_t *retlen)
+{
+ return -EINVAL;
+}
+
+/*
+ * NAND erase a block
+ */
+static int nand_erase (struct mtd_info *mtd, struct erase_info *instr)
+{
+ int i, nBlocks,block;
+
+ DEBUG (MTD_DEBUG_LEVEL3,
+ "nand_erase: start = 0x%08x, len = %i\n",
+ (unsigned int) instr->addr, (unsigned int) instr->len);
+
+ /* Start address must align on block boundary */
+ if (instr->addr & (mtd->erasesize - 1)) {
+ DEBUG (MTD_DEBUG_LEVEL0,
+ "nand_erase: Unaligned address\n");
+ return -EINVAL;
+ }
+
+ /* Length must align on block boundary */
+ if (instr->len & (mtd->erasesize - 1)) {
+ DEBUG (MTD_DEBUG_LEVEL0,
+ "nand_erase: Length not block aligned\n");
+ return -EINVAL;
+ }
+
+ /* Do not allow erase past end of device */
+ if ((instr->len + instr->addr) > mtd->size) {
+ DEBUG (MTD_DEBUG_LEVEL0,
+ "nand_erase: Erase past end of device\n");
+ return -EINVAL;
+ }
+
+ nBlocks = instr->len >> (NAND_SHIFT + 5);
+ block = instr->addr >> (NAND_SHIFT + 5);
+
+ for(i = 0; i < nBlocks; i++)
+ {
+ nandemul_DoErase(block);
+ block++;
+ }
+
+
+
+ return 0;
+
+
+}
+
+/*
+ * NAND sync
+ */
+static void nand_sync (struct mtd_info *mtd)
+{
+ DEBUG (MTD_DEBUG_LEVEL3, "nand_sync: called\n");
+
+}
+
+/*
+ * Scan for the NAND device
+ */
+int nand_scan (struct mtd_info *mtd)
+{
+ mtd->oobblock = 512;
+ mtd->oobsize = 16;
+ mtd->erasesize = 512 * 32;
+ mtd->size = sizeInMB * 1024*1024;
+
+
+
+ /* Fill in remaining MTD driver data */
+ mtd->type = MTD_NANDFLASH;
+ mtd->flags = MTD_CAP_NANDFLASH;
+ mtd->module = THIS_MODULE;
+ mtd->ecctype = MTD_ECC_NONE;
+ mtd->erase = nand_erase;
+ mtd->point = NULL;
+ mtd->unpoint = NULL;
+ mtd->read = nand_read;
+ mtd->write = nand_write;
+ mtd->read_ecc = nand_read_ecc;
+ mtd->write_ecc = nand_write_ecc;
+ mtd->read_oob = nand_read_oob;
+ mtd->write_oob = nand_write_oob;
+ mtd->readv = NULL;
+ mtd->writev = nand_writev;
+ mtd->sync = nand_sync;
+ mtd->lock = NULL;
+ mtd->unlock = NULL;
+ mtd->suspend = NULL;
+ mtd->resume = NULL;
+
+ /* Return happy */
+ return 0;
+}
+
+#if 0
+#ifdef MODULE
+MODULE_PARM(sizeInMB, "i");
+
+__setup("sizeInMB=",sizeInMB);
+#endif
+#endif
+
+/*
+ * Define partitions for flash devices
+ */
+
+static struct mtd_partition nandemul_partition[] =
+{
+ { name: "NANDemul partition 1",
+ offset: 0,
+ size: 0 },
+};
+
+static int nPartitions = sizeof(nandemul_partition)/sizeof(nandemul_partition[0]);
+
+/*
+ * Main initialization routine
+ */
+int __init nandemul_init (void)
+{
+
+ // Do the nand init
+
+ nand_scan(&nandemul_mtd);
+
+ nandemul_Initialise();
+
+ // Build the partition table
+
+ nandemul_partition[0].size = sizeInMB * 1024 * 1024;
+
+ // Register the partition
+ add_mtd_partitions(&nandemul_mtd,nandemul_partition,nPartitions);
+
+ return 0;
+
+}
+
+module_init(nandemul_init);
+
+/*
+ * Clean up routine
+ */
+#ifdef MODULE
+static void __exit nandemul_cleanup (void)
+{
+
+ nandemul_DeInitialise();
+
+ /* Unregister partitions */
+ del_mtd_partitions(&nandemul_mtd);
+
+ /* Unregister the device */
+ del_mtd_device (&nandemul_mtd);
+
+}
+module_exit(nandemul_cleanup);
+#endif
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Charles Manning <manningc@aleph1.co.uk>");
+MODULE_DESCRIPTION("NAND emulated in RAM");
+
+
+
+