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/*
* Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
* With help from the common/soft_spi and 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 <spi.h>
#include <asm/mpc8xxx_spi.h>
#ifdef CONFIG_HARD_SPI
#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_PRESCALER(reg, div) (reg)=((reg) & 0xfff0ffff) | ((div)<<16)
#define SPI_CHARLENGTH(reg, div) (reg)=((reg) & 0xff0fffff) | ((div)<<20)
#define SPI_TIMEOUT 1000
void spi_init(void)
{
volatile spi8xxx_t *spi = &((immap_t *) (CFG_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_PRESCALER(spi->mode, 1); /* 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_xfer(spi_chipsel_type chipsel, int bitlen, uchar * dout, uchar * din)
{
volatile spi8xxx_t *spi = &((immap_t *) (CFG_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: chipsel %08X dout %08X din %08X bitlen %d\n",
(int)chipsel, *(uint *) dout, *(uint *) din, bitlen);
if (chipsel != NULL)
(*chipsel) (1); /* select the target chip */
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
* l <= 4 3
* 4 < l <= 16 l - 1
* l > 16 0
*/
if (bitlen <= 16)
SPI_CHARLENGTH(spi->mode, bitlen <= 4 ? 3 : bitlen - 1);
else {
SPI_CHARLENGTH(spi->mode, 0);
/* 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 (chipsel != NULL)
(*chipsel) (0); /* deselect the target chip */
return 0;
}
#endif /* CONFIG_HARD_SPI */
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