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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2011, 2012 Cavium, Inc.
*/
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/io.h>
#include "spi-cavium.h"
static void octeon_spi_wait_ready(struct octeon_spi *p)
{
union cvmx_mpi_sts mpi_sts;
unsigned int loops = 0;
do {
if (loops++)
__delay(500);
mpi_sts.u64 = readq(p->register_base + OCTEON_SPI_STS(p));
} while (mpi_sts.s.busy);
}
static int octeon_spi_do_transfer(struct octeon_spi *p,
struct spi_message *msg,
struct spi_transfer *xfer,
bool last_xfer)
{
struct spi_device *spi = msg->spi;
union cvmx_mpi_cfg mpi_cfg;
union cvmx_mpi_tx mpi_tx;
unsigned int clkdiv;
int mode;
bool cpha, cpol;
const u8 *tx_buf;
u8 *rx_buf;
int len;
int i;
mode = spi->mode;
cpha = mode & SPI_CPHA;
cpol = mode & SPI_CPOL;
clkdiv = p->sys_freq / (2 * xfer->speed_hz);
mpi_cfg.u64 = 0;
mpi_cfg.s.clkdiv = clkdiv;
mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0;
mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0;
mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0;
mpi_cfg.s.idlelo = cpha != cpol;
mpi_cfg.s.cslate = cpha ? 1 : 0;
mpi_cfg.s.enable = 1;
if (spi->chip_select < 4)
p->cs_enax |= 1ull << (12 + spi->chip_select);
mpi_cfg.u64 |= p->cs_enax;
if (mpi_cfg.u64 != p->last_cfg) {
p->last_cfg = mpi_cfg.u64;
writeq(mpi_cfg.u64, p->register_base + OCTEON_SPI_CFG(p));
}
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
len = xfer->len;
while (len > OCTEON_SPI_MAX_BYTES) {
for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
u8 d;
if (tx_buf)
d = *tx_buf++;
else
d = 0;
writeq(d, p->register_base + OCTEON_SPI_DAT0(p) + (8 * i));
}
mpi_tx.u64 = 0;
mpi_tx.s.csid = spi->chip_select;
mpi_tx.s.leavecs = 1;
mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0;
mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES;
writeq(mpi_tx.u64, p->register_base + OCTEON_SPI_TX(p));
octeon_spi_wait_ready(p);
if (rx_buf)
for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) {
u64 v = readq(p->register_base + OCTEON_SPI_DAT0(p) + (8 * i));
*rx_buf++ = (u8)v;
}
len -= OCTEON_SPI_MAX_BYTES;
}
for (i = 0; i < len; i++) {
u8 d;
if (tx_buf)
d = *tx_buf++;
else
d = 0;
writeq(d, p->register_base + OCTEON_SPI_DAT0(p) + (8 * i));
}
mpi_tx.u64 = 0;
mpi_tx.s.csid = spi->chip_select;
if (last_xfer)
mpi_tx.s.leavecs = xfer->cs_change;
else
mpi_tx.s.leavecs = !xfer->cs_change;
mpi_tx.s.txnum = tx_buf ? len : 0;
mpi_tx.s.totnum = len;
writeq(mpi_tx.u64, p->register_base + OCTEON_SPI_TX(p));
octeon_spi_wait_ready(p);
if (rx_buf)
for (i = 0; i < len; i++) {
u64 v = readq(p->register_base + OCTEON_SPI_DAT0(p) + (8 * i));
*rx_buf++ = (u8)v;
}
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
return xfer->len;
}
int octeon_spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct octeon_spi *p = spi_master_get_devdata(master);
unsigned int total_len = 0;
int status = 0;
struct spi_transfer *xfer;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
bool last_xfer = list_is_last(&xfer->transfer_list,
&msg->transfers);
int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer);
if (r < 0) {
status = r;
goto err;
}
total_len += r;
}
err:
msg->status = status;
msg->actual_length = total_len;
spi_finalize_current_message(master);
return status;
}
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