Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 559 insertions, 0 deletions

diff --git a/drivers/mtd/nand/rtc_from4.c b/drivers/mtd/nand/rtc_from4.c
new file mode 100644
index 000000000000..02305a2adca7
--- /dev/null
+++ b/drivers/mtd/nand/rtc_from4.c
@@ -0,0 +1,559 @@
+/*
+ *  drivers/mtd/nand/rtc_from4.c
+ *
+ *  Copyright (C) 2004  Red Hat, Inc.
+ * 
+ *  Derived from drivers/mtd/nand/spia.c
+ *       Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)
+ *
+ * $Id: rtc_from4.c,v 1.7 2004/11/04 12:53:10 gleixner Exp $
+ *
+ * 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.
+ *
+ * Overview:
+ *   This is a device driver for the AG-AND flash device found on the
+ *   Renesas Technology Corp. Flash ROM 4-slot interface board (FROM_BOARD4), 
+ *   which utilizes the Renesas HN29V1G91T-30 part. 
+ *   This chip is a 1 GBibit (128MiB x 8 bits) AG-AND flash device.
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/rslib.h>
+#include <linux/module.h>
+#include <linux/mtd/compatmac.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+#include <asm/io.h>
+
+/*
+ * MTD structure for Renesas board
+ */
+static struct mtd_info *rtc_from4_mtd = NULL;
+
+#define RTC_FROM4_MAX_CHIPS     2
+
+/* HS77x9 processor register defines */
+#define SH77X9_BCR1     ((volatile unsigned short *)(0xFFFFFF60))
+#define SH77X9_BCR2     ((volatile unsigned short *)(0xFFFFFF62))
+#define SH77X9_WCR1     ((volatile unsigned short *)(0xFFFFFF64))
+#define SH77X9_WCR2     ((volatile unsigned short *)(0xFFFFFF66))
+#define SH77X9_MCR      ((volatile unsigned short *)(0xFFFFFF68))
+#define SH77X9_PCR      ((volatile unsigned short *)(0xFFFFFF6C))
+#define SH77X9_FRQCR    ((volatile unsigned short *)(0xFFFFFF80))
+
+/*
+ * Values specific to the Renesas Technology Corp. FROM_BOARD4 (used with HS77x9 processor)
+ */
+/* Address where flash is mapped */
+#define RTC_FROM4_FIO_BASE      0x14000000
+
+/* CLE and ALE are tied to address lines 5 & 4, respectively */
+#define RTC_FROM4_CLE           (1 << 5)
+#define RTC_FROM4_ALE           (1 << 4)
+
+/* address lines A24-A22 used for chip selection */
+#define RTC_FROM4_NAND_ADDR_SLOT3       (0x00800000)
+#define RTC_FROM4_NAND_ADDR_SLOT4       (0x00C00000)
+#define RTC_FROM4_NAND_ADDR_FPGA        (0x01000000)
+/* mask address lines A24-A22 used for chip selection */
+#define RTC_FROM4_NAND_ADDR_MASK        (RTC_FROM4_NAND_ADDR_SLOT3 | RTC_FROM4_NAND_ADDR_SLOT4 | RTC_FROM4_NAND_ADDR_FPGA)
+
+/* FPGA status register for checking device ready (bit zero) */
+#define RTC_FROM4_FPGA_SR               (RTC_FROM4_NAND_ADDR_FPGA | 0x00000002)
+#define RTC_FROM4_DEVICE_READY          0x0001
+
+/* FPGA Reed-Solomon ECC Control register */
+
+#define RTC_FROM4_RS_ECC_CTL            (RTC_FROM4_NAND_ADDR_FPGA | 0x00000050)
+#define RTC_FROM4_RS_ECC_CTL_CLR        (1 << 7)
+#define RTC_FROM4_RS_ECC_CTL_GEN        (1 << 6)
+#define RTC_FROM4_RS_ECC_CTL_FD_E       (1 << 5)
+
+/* FPGA Reed-Solomon ECC code base */
+#define RTC_FROM4_RS_ECC                (RTC_FROM4_NAND_ADDR_FPGA | 0x00000060)
+#define RTC_FROM4_RS_ECCN               (RTC_FROM4_NAND_ADDR_FPGA | 0x00000080)
+
+/* FPGA Reed-Solomon ECC check register */
+#define RTC_FROM4_RS_ECC_CHK            (RTC_FROM4_NAND_ADDR_FPGA | 0x00000070)
+#define RTC_FROM4_RS_ECC_CHK_ERROR      (1 << 7)
+
+/* Undefine for software ECC */
+#define RTC_FROM4_HWECC 1
+
+/*
+ * Module stuff
+ */
+static void __iomem *rtc_from4_fio_base = P2SEGADDR(RTC_FROM4_FIO_BASE);
+
+const static struct mtd_partition partition_info[] = {
+        {
+                .name   = "Renesas flash partition 1",
+                .offset = 0,
+                .size   = MTDPART_SIZ_FULL
+        },
+};
+#define NUM_PARTITIONS 1
+
+/* 
+ *      hardware specific flash bbt decriptors
+ *      Note: this is to allow debugging by disabling 
+ *              NAND_BBT_CREATE and/or NAND_BBT_WRITE
+ *
+ */
+static uint8_t bbt_pattern[] = {'B', 'b', 't', '0' };
+static uint8_t mirror_pattern[] = {'1', 't', 'b', 'B' };
+
+static struct nand_bbt_descr rtc_from4_bbt_main_descr = {
+        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+                | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
+        .offs = 40,
+        .len = 4,
+        .veroffs = 44,
+        .maxblocks = 4,
+        .pattern = bbt_pattern
+};
+
+static struct nand_bbt_descr rtc_from4_bbt_mirror_descr = {
+        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
+                | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
+        .offs = 40,
+        .len = 4,
+        .veroffs = 44,
+        .maxblocks = 4,
+        .pattern = mirror_pattern
+};
+
+
+
+#ifdef RTC_FROM4_HWECC
+
+/* the Reed Solomon control structure */
+static struct rs_control *rs_decoder;
+
+/* 
+ *      hardware specific Out Of Band information
+ */
+static struct nand_oobinfo rtc_from4_nand_oobinfo = {
+        .useecc = MTD_NANDECC_AUTOPLACE,
+        .eccbytes = 32,
+        .eccpos = {
+                 0,  1,  2,  3,  4,  5,  6,  7,
+                 8,  9, 10, 11, 12, 13, 14, 15,
+                16, 17, 18, 19, 20, 21, 22, 23,
+                24, 25, 26, 27, 28, 29, 30, 31},
+        .oobfree = { {32, 32} }
+};
+
+/* Aargh. I missed the reversed bit order, when I
+ * was talking to Renesas about the FPGA.
+ *
+ * The table is used for bit reordering and inversion
+ * of the ecc byte which we get from the FPGA
+ */
+static uint8_t revbits[256] = {
+        0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
+        0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
+        0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
+        0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
+        0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
+        0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
+        0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
+        0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
+        0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
+        0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
+        0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
+        0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
+        0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
+        0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
+        0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
+        0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
+        0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
+        0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
+        0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
+        0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
+        0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
+        0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
+        0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
+        0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
+        0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
+        0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
+        0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
+        0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
+        0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
+        0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
+        0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
+        0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
+};
+
+#endif
+
+
+
+/* 
+ * rtc_from4_hwcontrol - hardware specific access to control-lines
+ * @mtd:        MTD device structure
+ * @cmd:        hardware control command
+ *
+ * Address lines (A5 and A4) are used to control Command and Address Latch 
+ * Enable on this board, so set the read/write address appropriately.
+ *
+ * Chip Enable is also controlled by the Chip Select (CS5) and 
+ * Address lines (A24-A22), so no action is required here.
+ *
+ */
+static void rtc_from4_hwcontrol(struct mtd_info *mtd, int cmd)
+{
+        struct nand_chip* this = (struct nand_chip *) (mtd->priv);
+        
+        switch(cmd) {
+                
+        case NAND_CTL_SETCLE: 
+                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W | RTC_FROM4_CLE);
+                break;
+        case NAND_CTL_CLRCLE: 
+                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W & ~RTC_FROM4_CLE);
+                break;
+                
+        case NAND_CTL_SETALE:
+                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W | RTC_FROM4_ALE);
+                break;
+        case NAND_CTL_CLRALE:
+                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W & ~RTC_FROM4_ALE);
+                break;
+                
+        case NAND_CTL_SETNCE:
+                break;
+        case NAND_CTL_CLRNCE:
+                break;
+
+        }
+}
+
+
+/*
+ * rtc_from4_nand_select_chip - hardware specific chip select
+ * @mtd:        MTD device structure
+ * @chip:       Chip to select (0 == slot 3, 1 == slot 4)
+ *
+ * The chip select is based on address lines A24-A22.
+ * This driver uses flash slots 3 and 4 (A23-A22).
+ *
+ */
+static void rtc_from4_nand_select_chip(struct mtd_info *mtd, int chip)
+{
+        struct nand_chip *this = mtd->priv;
+
+        this->IO_ADDR_R = (void __iomem *)((unsigned long)this->IO_ADDR_R & ~RTC_FROM4_NAND_ADDR_MASK);
+        this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W & ~RTC_FROM4_NAND_ADDR_MASK);
+
+        switch(chip) {
+
+        case 0:         /* select slot 3 chip */
+                this->IO_ADDR_R = (void __iomem *)((unsigned long)this->IO_ADDR_R | RTC_FROM4_NAND_ADDR_SLOT3);
+                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W | RTC_FROM4_NAND_ADDR_SLOT3);
+                break;
+        case 1:         /* select slot 4 chip */
+                this->IO_ADDR_R = (void __iomem *)((unsigned long)this->IO_ADDR_R | RTC_FROM4_NAND_ADDR_SLOT4);
+                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W | RTC_FROM4_NAND_ADDR_SLOT4);
+                break;
+
+        }
+}
+
+
+
+/*
+ * rtc_from4_nand_device_ready - hardware specific ready/busy check
+ * @mtd:        MTD device structure
+ *
+ * This board provides the Ready/Busy state in the status register
+ * of the FPGA.  Bit zero indicates the RDY(1)/BSY(0) signal.
+ *
+ */
+static int rtc_from4_nand_device_ready(struct mtd_info *mtd)
+{
+        unsigned short status;
+
+        status = *((volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_FPGA_SR));
+
+        return (status & RTC_FROM4_DEVICE_READY);
+
+}
+
+#ifdef RTC_FROM4_HWECC
+/*
+ * rtc_from4_enable_hwecc - hardware specific hardware ECC enable function
+ * @mtd:        MTD device structure
+ * @mode:       I/O mode; read or write
+ *
+ * enable hardware ECC for data read or write 
+ *
+ */
+static void rtc_from4_enable_hwecc(struct mtd_info *mtd, int mode)
+{
+        volatile unsigned short * rs_ecc_ctl = (volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECC_CTL);
+        unsigned short status;
+
+        switch (mode) {
+            case NAND_ECC_READ :
+                status =  RTC_FROM4_RS_ECC_CTL_CLR 
+                        | RTC_FROM4_RS_ECC_CTL_FD_E;
+
+                *rs_ecc_ctl = status;
+                break;
+
+            case NAND_ECC_READSYN :
+                status =  0x00;
+
+                *rs_ecc_ctl = status;
+                break;
+
+            case NAND_ECC_WRITE :
+                status =  RTC_FROM4_RS_ECC_CTL_CLR 
+                        | RTC_FROM4_RS_ECC_CTL_GEN 
+                        | RTC_FROM4_RS_ECC_CTL_FD_E;
+
+                *rs_ecc_ctl = status;
+                break;
+
+            default:
+                BUG();
+                break;
+        }
+
+}
+
+/*
+ * rtc_from4_calculate_ecc - hardware specific code to read ECC code
+ * @mtd:        MTD device structure
+ * @dat:        buffer containing the data to generate ECC codes
+ * @ecc_code    ECC codes calculated
+ *
+ * The ECC code is calculated by the FPGA.  All we have to do is read the values
+ * from the FPGA registers.
+ *
+ * Note: We read from the inverted registers, since data is inverted before
+ * the code is calculated. So all 0xff data (blank page) results in all 0xff rs code
+ *
+ */
+static void rtc_from4_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code)
+{
+        volatile unsigned short * rs_eccn = (volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECCN);
+        unsigned short value;
+        int i;
+
+        for (i = 0; i < 8; i++) {
+                value = *rs_eccn;
+                ecc_code[i] = (unsigned char)value;
+                rs_eccn++;
+        }
+        ecc_code[7] |= 0x0f;    /* set the last four bits (not used) */
+}
+
+/*
+ * rtc_from4_correct_data - hardware specific code to correct data using ECC code
+ * @mtd:        MTD device structure
+ * @buf:        buffer containing the data to generate ECC codes
+ * @ecc1        ECC codes read
+ * @ecc2        ECC codes calculated
+ *
+ * The FPGA tells us fast, if there's an error or not. If no, we go back happy
+ * else we read the ecc results from the fpga and call the rs library to decode
+ * and hopefully correct the error
+ *
+ * For now I use the code, which we read from the FLASH to use the RS lib,
+ * as the syndrom conversion has a unresolved issue.
+ */
+static int rtc_from4_correct_data(struct mtd_info *mtd, const u_char *buf, u_char *ecc1, u_char *ecc2)
+{
+        int i, j, res;
+        unsigned short status; 
+        uint16_t par[6], syn[6], tmp;
+        uint8_t ecc[8];
+        volatile unsigned short *rs_ecc;
+
+        status = *((volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECC_CHK));
+
+        if (!(status & RTC_FROM4_RS_ECC_CHK_ERROR)) {
+                return 0;
+        }
+
+        /* Read the syndrom pattern from the FPGA and correct the bitorder */
+        rs_ecc = (volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECC);
+        for (i = 0; i < 8; i++) {
+                ecc[i] = revbits[(*rs_ecc) & 0xFF];
+                rs_ecc++;
+        }
+
+        /* convert into 6 10bit syndrome fields */
+        par[5] = rs_decoder->index_of[(((uint16_t)ecc[0] >> 0) & 0x0ff) | 
+                                      (((uint16_t)ecc[1] << 8) & 0x300)];
+        par[4] = rs_decoder->index_of[(((uint16_t)ecc[1] >> 2) & 0x03f) |
+                                      (((uint16_t)ecc[2] << 6) & 0x3c0)];
+        par[3] = rs_decoder->index_of[(((uint16_t)ecc[2] >> 4) & 0x00f) |
+                                      (((uint16_t)ecc[3] << 4) & 0x3f0)];
+        par[2] = rs_decoder->index_of[(((uint16_t)ecc[3] >> 6) & 0x003) |
+                                      (((uint16_t)ecc[4] << 2) & 0x3fc)];
+        par[1] = rs_decoder->index_of[(((uint16_t)ecc[5] >> 0) & 0x0ff) |
+                                      (((uint16_t)ecc[6] << 8) & 0x300)];
+        par[0] = (((uint16_t)ecc[6] >> 2) & 0x03f) | (((uint16_t)ecc[7] << 6) & 0x3c0);
+
+        /* Convert to computable syndrome */
+        for (i = 0; i < 6; i++) {
+                syn[i] = par[0];
+                for (j = 1; j < 6; j++)
+                        if (par[j] != rs_decoder->nn)
+                                syn[i] ^= rs_decoder->alpha_to[rs_modnn(rs_decoder, par[j] + i * j)];
+
+                /* Convert to index form */
+                syn[i] = rs_decoder->index_of[syn[i]];
+        }
+
+        /* Let the library code do its magic.*/
+        res = decode_rs8(rs_decoder, buf, par, 512, syn, 0, NULL, 0xff, NULL);
+        if (res > 0) {
+                DEBUG (MTD_DEBUG_LEVEL0, "rtc_from4_correct_data: " 
+                        "ECC corrected %d errors on read\n", res);
+        }
+        return res;
+}
+#endif
+
+/*
+ * Main initialization routine
+ */
+int __init rtc_from4_init (void)
+{
+        struct nand_chip *this;
+        unsigned short bcr1, bcr2, wcr2;
+
+        /* Allocate memory for MTD device structure and private data */
+        rtc_from4_mtd = kmalloc(sizeof(struct mtd_info) + sizeof (struct nand_chip),
+                                GFP_KERNEL);
+        if (!rtc_from4_mtd) {
+                printk ("Unable to allocate Renesas NAND MTD device structure.\n");
+                return -ENOMEM;
+        }
+
+        /* Get pointer to private data */
+        this = (struct nand_chip *) (&rtc_from4_mtd[1]);
+
+        /* Initialize structures */
+        memset((char *) rtc_from4_mtd, 0, sizeof(struct mtd_info));
+        memset((char *) this, 0, sizeof(struct nand_chip));
+
+        /* Link the private data with the MTD structure */
+        rtc_from4_mtd->priv = this;
+
+        /* set area 5 as PCMCIA mode to clear the spec of tDH(Data hold time;9ns min) */
+        bcr1 = *SH77X9_BCR1 & ~0x0002;
+        bcr1 |= 0x0002;
+        *SH77X9_BCR1 = bcr1;
+
+        /* set */
+        bcr2 = *SH77X9_BCR2 & ~0x0c00;
+        bcr2 |= 0x0800;
+        *SH77X9_BCR2 = bcr2;
+
+        /* set area 5 wait states */
+        wcr2 = *SH77X9_WCR2 & ~0x1c00;
+        wcr2 |= 0x1c00;
+        *SH77X9_WCR2 = wcr2;
+
+        /* Set address of NAND IO lines */
+        this->IO_ADDR_R = rtc_from4_fio_base;
+        this->IO_ADDR_W = rtc_from4_fio_base;
+        /* Set address of hardware control function */
+        this->hwcontrol = rtc_from4_hwcontrol;
+        /* Set address of chip select function */
+        this->select_chip = rtc_from4_nand_select_chip;
+        /* command delay time (in us) */
+        this->chip_delay = 100;
+        /* return the status of the Ready/Busy line */
+        this->dev_ready = rtc_from4_nand_device_ready;
+
+#ifdef RTC_FROM4_HWECC
+        printk(KERN_INFO "rtc_from4_init: using hardware ECC detection.\n");
+
+        this->eccmode = NAND_ECC_HW8_512;
+        this->options |= NAND_HWECC_SYNDROME;
+        /* set the nand_oobinfo to support FPGA H/W error detection */
+        this->autooob = &rtc_from4_nand_oobinfo;
+        this->enable_hwecc = rtc_from4_enable_hwecc;
+        this->calculate_ecc = rtc_from4_calculate_ecc;
+        this->correct_data = rtc_from4_correct_data;
+#else
+        printk(KERN_INFO "rtc_from4_init: using software ECC detection.\n");
+
+        this->eccmode = NAND_ECC_SOFT;
+#endif
+
+        /* set the bad block tables to support debugging */
+        this->bbt_td = &rtc_from4_bbt_main_descr;
+        this->bbt_md = &rtc_from4_bbt_mirror_descr;
+
+        /* Scan to find existence of the device */
+        if (nand_scan(rtc_from4_mtd, RTC_FROM4_MAX_CHIPS)) {
+                kfree(rtc_from4_mtd);
+                return -ENXIO;
+        }
+
+        /* Register the partitions */
+        add_mtd_partitions(rtc_from4_mtd, partition_info, NUM_PARTITIONS);
+
+#ifdef RTC_FROM4_HWECC
+        /* We could create the decoder on demand, if memory is a concern.
+         * This way we have it handy, if an error happens 
+         *
+         * Symbolsize is 10 (bits)
+         * Primitve polynomial is x^10+x^3+1
+         * first consecutive root is 0
+         * primitve element to generate roots = 1
+         * generator polinomial degree = 6
+         */
+        rs_decoder = init_rs(10, 0x409, 0, 1, 6);
+        if (!rs_decoder) {
+                printk (KERN_ERR "Could not create a RS decoder\n");
+                nand_release(rtc_from4_mtd);
+                kfree(rtc_from4_mtd);
+                return -ENOMEM;
+        }
+#endif
+        /* Return happy */
+        return 0;
+}
+module_init(rtc_from4_init);
+
+
+/*
+ * Clean up routine
+ */
+#ifdef MODULE
+static void __exit rtc_from4_cleanup (void)
+{
+        /* Release resource, unregister partitions */
+        nand_release(rtc_from4_mtd);
+
+        /* Free the MTD device structure */
+        kfree (rtc_from4_mtd);
+
+#ifdef RTC_FROM4_HWECC
+        /* Free the reed solomon resources */
+        if (rs_decoder) {
+                free_rs(rs_decoder);
+        }
+#endif
+}
+module_exit(rtc_from4_cleanup);
+#endif
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("d.marlin <dmarlin@redhat.com");
+MODULE_DESCRIPTION("Board-specific glue layer for AG-AND flash on Renesas FROM_BOARD4");
+