/*
 * Copyright (c) 2004 Picture Elements, Inc.
 *    Stephen Williams (XXXXXXXXXXXXXXXX)
 *
 *    This source code is free software; you can redistribute it
 *    and/or modify it in source code form under the terms of the GNU
 *    General Public License as published by the Free Software
 *    Foundation; either version 2 of the License, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */
#ident "$Id:$"

/*
 * The Xilinx SystemACE chip support is activated by defining
 * CONFIG_SYSTEMACE to turn on support, and CFG_SYSTEMACE_BASE
 * to set the base address of the device. This code currently
 * assumes that the chip is connected via a byte-wide bus.
 *
 * The CONFIG_SYSTEMACE also adds to fat support the device class
 * "ace" that allows the user to execute "fatls ace 0" and the
 * like. This works by making the systemace_get_dev function
 * available to cmd_fat.c:get_dev and filling in a block device
 * description that has all the bits needed for FAT support to
 * read sectors.
 */

# include  <common.h>
# include  <command.h>
# include  <systemace.h>
# include  <part.h>
# include  <asm/io.h>

#ifdef CONFIG_SYSTEMACE

/*
 * The ace_readw and writew functions read/write 16bit words, but the
 * offset value is the BYTE offset as most used in the Xilinx
 * datasheet for the SystemACE chip. The CFG_SYSTEMACE_BASE is defined
 * to be the base address for the chip, usually in the local
 * peripheral bus.
 */
static unsigned ace_readw(unsigned offset)
{
      return readw(CFG_SYSTEMACE_BASE+offset);
}

static void ace_writew(unsigned val, unsigned offset)
{
      writew(val, CFG_SYSTEMACE_BASE+offset);
}

/* */

static unsigned long systemace_read(int dev,
				    unsigned long start,
				    unsigned long blkcnt,
				    unsigned long *buffer);

static block_dev_desc_t systemace_dev = {0};

static int get_cf_lock(void)
{
      int retry = 10;

	/* CONTROLREG = LOCKREG */
      ace_writew(0x0002, 0x18);

	/* Wait for MPULOCK in STATUSREG[15:0] */
      while (! (ace_readw(0x04) & 0x0002)) {

	    if (retry < 0)
		  return -1;

	    udelay(100000);
	    retry -= 1;
      }

      return 0;
}

static void release_cf_lock(void)
{
	/* CONTROLREG = none */
      ace_writew(0x0000, 0x18);
}

block_dev_desc_t *  systemace_get_dev(int dev)
{
	/* The first time through this, the systemace_dev object is
	   not yet initialized. In that case, fill it in. */
      if (systemace_dev.blksz == 0) {
	    systemace_dev.if_type   = IF_TYPE_UNKNOWN;
	    systemace_dev.part_type = PART_TYPE_UNKNOWN;
	    systemace_dev.type      = DEV_TYPE_HARDDISK;
	    systemace_dev.blksz     = 512;
	    systemace_dev.removable = 1;
	    systemace_dev.block_read = systemace_read;
      }

      return &systemace_dev;
}

/*
 * This function is called (by dereferencing the block_read pointer in
 * the dev_desc) to read blocks of data. The return value is the
 * number of blocks read. A zero return indicates an error.
 */
static unsigned long systemace_read(int dev,
				    unsigned long start,
				    unsigned long blkcnt,
				    unsigned long *buffer)
{
      int retry;
      unsigned blk_countdown;
      unsigned char*dp = (unsigned char*)buffer;

      if (get_cf_lock() < 0) {
	    unsigned status = ace_readw(0x04);

	      /* If CFDETECT is false, card is missing. */
	    if (! (status&0x0010)) {
		  printf("** CompactFlash card not present. **\n");
		  return 0;
	    }

	    printf("**** ACE locked away from me (STATUSREG=%04x)\n", status);
	    return 0;
      }

#ifdef DEBUG_SYSTEMACE
      printf("... systemace read %lu sectors at %lu\n", blkcnt, start);
#endif

      retry = 2000;
      for (;;) {
	    unsigned val = ace_readw(0x04);

	      /* If CFDETECT is false, card is missing. */
	    if (! (val & 0x0010)) {
		  printf("**** ACE CompactFlash not found.\n");
		  release_cf_lock();
		  return 0;
	    }

	      /* If RDYFORCMD, then we are ready to go. */
	    if (val & 0x0100)
		  break;

	    if (retry < 0) {
		  printf("**** SystemACE not ready.\n");
		  release_cf_lock();
		  return 0;
	    }

	    udelay(1000);
	    retry -= 1;
      }

	/* The SystemACE can only transfer 256 sectors at a time, so
	   limit the current chunk of sectors. The blk_countdown
	   variable is the number of sectors left to transfer. */

      blk_countdown = blkcnt;
      while (blk_countdown > 0) {
	    unsigned trans = blk_countdown;

	    if (trans > 256) trans = 256;

#ifdef DEBUG_SYSTEMACE
	    printf("... transfer %lu sector in a chunk\n", trans);
#endif
	      /* Write LBA block address */
	    ace_writew((start>> 0) & 0xffff, 0x10);
	    ace_writew((start>>16) & 0x00ff, 0x12);

	      /* NOTE: in the Write Sector count below, a count of 0
		 causes a transfer of 256, so &0xff gives the right
		 value for whatever transfer count we want. */

	      /* Write sector count | ReadMemCardData. */
	    ace_writew((trans&0xff) | 0x0300, 0x14);

	    retry = trans * 16;
	    while (retry > 0) {
		  int idx;

		    /* Wait for buffer to become ready. */
		  while (! (ace_readw(0x04) & 0x0020)) {
			udelay(100);
		  }

		    /* Read 16 words of 2bytes from the sector buffer. */
		  for (idx = 0 ;  idx < 16 ;  idx += 1) {
			unsigned short val = ace_readw(0x40);
			*dp++ = val & 0xff;
			*dp++ = (val>>8) & 0xff;
		  }

		  retry -= 1;
	    }

	      /* Count the blocks we transfer this time. */
	    start += trans;
	    blk_countdown -= trans;
      }

      release_cf_lock();

      return blkcnt;
}
#endif	/* CONFIG_SYSTEMACE */