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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/platform_device.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of.h>
#include <asm/octeon/octeon.h>
#include <asm/octeon/cvmx-mpi-defs.h>
#define OCTEON_SPI_CFG 0
#define OCTEON_SPI_STS 0x08
#define OCTEON_SPI_TX 0x10
#define OCTEON_SPI_DAT0 0x80
#define OCTEON_SPI_MAX_BYTES 9
#define OCTEON_SPI_MAX_CLOCK_HZ 16000000
struct octeon_spi {
void __iomem *register_base;
u64 last_cfg;
u64 cs_enax;
};
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);
} 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;
unsigned int speed_hz;
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;
speed_hz = xfer->speed_hz;
clkdiv = octeon_get_io_clock_rate() / (2 * 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);
}
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 + (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);
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 + (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 + (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);
octeon_spi_wait_ready(p);
if (rx_buf)
for (i = 0; i < len; i++) {
u64 v = readq(p->register_base + OCTEON_SPI_DAT0 + (8 * i));
*rx_buf++ = (u8)v;
}
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
return xfer->len;
}
static 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;
}
static int octeon_spi_probe(struct platform_device *pdev)
{
struct resource *res_mem;
void __iomem *reg_base;
struct spi_master *master;
struct octeon_spi *p;
int err = -ENOENT;
master = spi_alloc_master(&pdev->dev, sizeof(struct octeon_spi));
if (!master)
return -ENOMEM;
p = spi_master_get_devdata(master);
platform_set_drvdata(pdev, master);
res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
reg_base = devm_ioremap_resource(&pdev->dev, res_mem);
if (IS_ERR(reg_base)) {
err = PTR_ERR(reg_base);
goto fail;
}
p->register_base = reg_base;
master->num_chipselect = 4;
master->mode_bits = SPI_CPHA |
SPI_CPOL |
SPI_CS_HIGH |
SPI_LSB_FIRST |
SPI_3WIRE;
master->transfer_one_message = octeon_spi_transfer_one_message;
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->max_speed_hz = OCTEON_SPI_MAX_CLOCK_HZ;
master->dev.of_node = pdev->dev.of_node;
err = devm_spi_register_master(&pdev->dev, master);
if (err) {
dev_err(&pdev->dev, "register master failed: %d\n", err);
goto fail;
}
dev_info(&pdev->dev, "OCTEON SPI bus driver\n");
return 0;
fail:
spi_master_put(master);
return err;
}
static int octeon_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct octeon_spi *p = spi_master_get_devdata(master);
/* Clear the CSENA* and put everything in a known state. */
writeq(0, p->register_base + OCTEON_SPI_CFG);
return 0;
}
static const struct of_device_id octeon_spi_match[] = {
{ .compatible = "cavium,octeon-3010-spi", },
{},
};
MODULE_DEVICE_TABLE(of, octeon_spi_match);
static struct platform_driver octeon_spi_driver = {
.driver = {
.name = "spi-octeon",
.of_match_table = octeon_spi_match,
},
.probe = octeon_spi_probe,
.remove = octeon_spi_remove,
};
module_platform_driver(octeon_spi_driver);
MODULE_DESCRIPTION("Cavium, Inc. OCTEON SPI bus driver");
MODULE_AUTHOR("David Daney");
MODULE_LICENSE("GPL");
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