text: /*
   * Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
   * With help from the common/soft_spi and arch/powerpc/cpu/mpc8260 drivers
   *
   * See file CREDITS for list of people who contributed to this
   * project.
   *
   * This program is free software; you can redistribute it and/or
   * modify it 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
   */
  
  #include <common.h>
  
  #include <malloc.h>
  #include <spi.h>
  #include <asm/mpc8xxx_spi.h>
  
  #define SPI_EV_NE	(0x80000000 >> 22)	/* Receiver Not Empty */
  #define SPI_EV_NF	(0x80000000 >> 23)	/* Transmitter Not Full */
  
  #define SPI_MODE_LOOP	(0x80000000 >> 1)	/* Loopback mode */
  #define SPI_MODE_REV	(0x80000000 >> 5)	/* Reverse mode - MSB first */
  #define SPI_MODE_MS	(0x80000000 >> 6)	/* Always master */
  #define SPI_MODE_EN	(0x80000000 >> 7)	/* Enable interface */
  
  #define SPI_TIMEOUT	1000
  
  struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  		unsigned int max_hz, unsigned int mode)
  {
  	struct spi_slave *slave;
  
  	if (!spi_cs_is_valid(bus, cs))
  		return NULL;
  
  	slave = malloc(sizeof(struct spi_slave));
  	if (!slave)
  		return NULL;
  
  	slave->bus = bus;
  	slave->cs = cs;
  
  	/*
  	 * TODO: Some of the code in spi_init() should probably move
  	 * here, or into spi_claim_bus() below.
  	 */
  
  	return slave;
  }
  
  void spi_free_slave(struct spi_slave *slave)
  {
  	free(slave);
  }
  
  void spi_init(void)
  {
  	volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
  
  	/*
  	 * SPI pins on the MPC83xx are not muxed, so all we do is initialize
  	 * some registers
  	 */
  	spi->mode = SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN;
  	spi->mode = (spi->mode & 0xfff0ffff) | (1 << 16); /* Use SYSCLK / 8
  							     (16.67MHz typ.) */
  	spi->event = 0xffffffff;	/* Clear all SPI events */
  	spi->mask = 0x00000000;	/* Mask  all SPI interrupts */
  	spi->com = 0;		/* LST bit doesn't do anything, so disregard */
  }
  
  int spi_claim_bus(struct spi_slave *slave)
  {
  	return 0;
  }
  
  void spi_release_bus(struct spi_slave *slave)
  {
  
  }
  
  int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
  		void *din, unsigned long flags)
  {
  	volatile spi8xxx_t *spi = &((immap_t *) (CONFIG_SYS_IMMR))->spi;
  	unsigned int tmpdout, tmpdin, event;
  	int numBlks = bitlen / 32 + (bitlen % 32 ? 1 : 0);
  	int tm, isRead = 0;
  	unsigned char charSize = 32;
  
  	debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n",
  	      slave->bus, slave->cs, *(uint *) dout, *(uint *) din, bitlen);
  
  	if (flags & SPI_XFER_BEGIN)
  		spi_cs_activate(slave);
  
  	spi->event = 0xffffffff;	/* Clear all SPI events */
  
  	/* handle data in 32-bit chunks */
  	while (numBlks--) {
  		tmpdout = 0;
  		charSize = (bitlen >= 32 ? 32 : bitlen);
  
  		/* Shift data so it's msb-justified */
  		tmpdout = *(u32 *) dout >> (32 - charSize);
  
  		/* The LEN field of the SPMODE register is set as follows:
  		 *
  		 * Bit length             setting
  		 * len <= 4               3
  		 * 4 < len <= 16          len - 1
  		 * len > 16               0
  		 */
  
  		if (bitlen <= 16) {
  			if (bitlen <= 4)
  				spi->mode = (spi->mode & 0xff0fffff) |
  				            (3 << 20);
  			else
  				spi->mode = (spi->mode & 0xff0fffff) |
  				            ((bitlen - 1) << 20);
  		} else {
  			spi->mode = (spi->mode & 0xff0fffff);
  			/* Set up the next iteration if sending > 32 bits */
  			bitlen -= 32;
  			dout += 4;
  		}
  
  		spi->tx = tmpdout;	/* Write the data out */
  		debug("*** spi_xfer: ... %08x written\n", tmpdout);
  
  		/*
  		 * Wait for SPI transmit to get out
  		 * or time out (1 second = 1000 ms)
  		 * The NE event must be read and cleared first
  		 */
  		for (tm = 0, isRead = 0; tm < SPI_TIMEOUT; ++tm) {
  			event = spi->event;
  			if (event & SPI_EV_NE) {
  				tmpdin = spi->rx;
  				spi->event |= SPI_EV_NE;
  				isRead = 1;
  
  				*(u32 *) din = (tmpdin << (32 - charSize));
  				if (charSize == 32) {
  					/* Advance output buffer by 32 bits */
  					din += 4;
  				}
  			}
  			/*
  			 * Only bail when we've had both NE and NF events.
  			 * This will cause timeouts on RO devices, so maybe
  			 * in the future put an arbitrary delay after writing
  			 * the device.  Arbitrary delays suck, though...
  			 */
  			if (isRead && (event & SPI_EV_NF))
  				break;
  		}
  		if (tm >= SPI_TIMEOUT)
  			puts("*** spi_xfer: Time out during SPI transfer");
  
  		debug("*** spi_xfer: transfer ended. Value=%08x\n", tmpdin);
  	}
  
  	if (flags & SPI_XFER_END)
  		spi_cs_deactivate(slave);
  
  	return 0;
  }
  