u-boot/drivers/spi/andes_spi.c

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/*
* Driver of Andes SPI Controller
*
* (C) Copyright 2011 Andes Technology
* Macpaul Lin <macpaul@andestech.com>
*
* 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/io.h>
#include "andes_spi.h"
void spi_init(void)
{
/* do nothing */
}
static void andes_spi_spit_en(struct andes_spi_slave *ds)
{
unsigned int dcr = readl(&ds->regs->dcr);
debug("%s: dcr: %x, write value: %x\n",
__func__, dcr, (dcr | ANDES_SPI_DCR_SPIT));
writel((dcr | ANDES_SPI_DCR_SPIT), &ds->regs->dcr);
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct andes_spi_slave *ds;
if (!spi_cs_is_valid(bus, cs))
return NULL;
ds = spi_alloc_slave(struct andes_spi_slave, bus, cs);
if (!ds)
return NULL;
ds->regs = (struct andes_spi_regs *)CONFIG_SYS_SPI_BASE;
/*
* The hardware of andes_spi will set its frequency according
* to APB/AHB bus clock. Hence the hardware doesn't allow changing of
* requency and so the user requested speed is always ignored.
*/
ds->freq = max_hz;
return &ds->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct andes_spi_slave *ds = to_andes_spi(slave);
free(ds);
}
int spi_claim_bus(struct spi_slave *slave)
{
struct andes_spi_slave *ds = to_andes_spi(slave);
unsigned int apb;
unsigned int baud;
/* Enable the SPI hardware */
writel(ANDES_SPI_CR_SPIRST, &ds->regs->cr);
udelay(1000);
/* setup format */
baud = ((CONFIG_SYS_CLK_FREQ / CONFIG_SYS_SPI_CLK / 2) - 1) & 0xFF;
/*
* SPI_CLK = AHB bus clock / ((BAUD + 1)*2)
* BAUD = AHB bus clock / SPI_CLK / 2) - 1
*/
apb = (readl(&ds->regs->apb) & 0xffffff00) | baud;
writel(apb, &ds->regs->apb);
/* no interrupts */
writel(0, &ds->regs->ie);
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
struct andes_spi_slave *ds = to_andes_spi(slave);
/* Disable the SPI hardware */
writel(ANDES_SPI_CR_SPIRST, &ds->regs->cr);
}
static int andes_spi_read(struct spi_slave *slave, unsigned int len,
u8 *rxp, unsigned long flags)
{
struct andes_spi_slave *ds = to_andes_spi(slave);
unsigned int i, left;
unsigned int data;
debug("%s: slave: %x, len: %d, rxp: %x, flags: %d\n",
__func__, slave, len, rxp, flags);
debug("%s: data: ", __func__);
while (len > 0) {
left = min(len, 4);
data = readl(&ds->regs->data);
debug(" ");
for (i = 0; i < left; i++) {
debug("%02x ", data & 0xff);
*rxp++ = data;
data >>= 8;
len--;
}
}
debug("\n");
return 0;
}
static int andes_spi_write(struct spi_slave *slave, unsigned int wlen,
unsigned int rlen, const u8 *txp, unsigned long flags)
{
struct andes_spi_slave *ds = to_andes_spi(slave);
unsigned int data;
unsigned int i, left;
unsigned int spit_enabled = 0;
debug("%s: slave: %x, wlen: %d, rlen: %d, txp: %x, flags: %x\n",
__func__, slave, wlen, rlen, txp, flags);
/* The value of wlen and rlen wrote to register must minus 1 */
if (rlen == 0) /* write only */
writel(ANDES_SPI_DCR_MODE_WO | ANDES_SPI_DCR_WCNT(wlen-1) |
ANDES_SPI_DCR_RCNT(0), &ds->regs->dcr);
else /* write then read */
writel(ANDES_SPI_DCR_MODE_WR | ANDES_SPI_DCR_WCNT(wlen-1) |
ANDES_SPI_DCR_RCNT(rlen-1), &ds->regs->dcr);
/* wait till SPIBSY is cleared */
while (readl(&ds->regs->st) & ANDES_SPI_ST_SPIBSY)
;
/* data write process */
debug("%s: txp: ", __func__);
while (wlen > 0) {
/* clear the data */
data = 0;
/* data are usually be read 32bits once a time */
left = min(wlen, 4);
for (i = 0; i < left; i++) {
debug("%x ", *txp);
data |= *txp++ << (i * 8);
wlen--;
}
debug("\n");
debug("data: %08x\n", data);
debug("streg before write: %08x\n", readl(&ds->regs->st));
/* wait till TXFULL is deasserted */
while (readl(&ds->regs->st) & ANDES_SPI_ST_TXFEL)
;
writel(data, &ds->regs->data);
debug("streg after write: %08x\n", readl(&ds->regs->st));
if (spit_enabled == 0) {
/* enable SPIT bit - trigger the tx and rx progress */
andes_spi_spit_en(ds);
spit_enabled = 1;
}
}
debug("\n");
return 0;
}
/*
* spi_xfer:
* Since andes_spi doesn't support independent command transaction,
* that is, write and than read must be operated in continuous
* execution, there is no need to set dcr and trigger spit again in
* RX process.
*/
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
unsigned int len;
static int op_nextime;
static u8 tmp_cmd[5];
static int tmp_wlen;
unsigned int i;
if (bitlen == 0)
/* Finish any previously submitted transfers */
goto out;
if (bitlen % 8) {
/* Errors always terminate an ongoing transfer */
flags |= SPI_XFER_END;
goto out;
}
len = bitlen / 8;
debug("%s: slave: %08x, bitlen: %d, dout: "
"%08x, din: %08x, flags: %d, len: %d\n",
__func__, slave, bitlen, dout, din, flags, len);
/*
* Important:
* andes_spi's hardware doesn't support 2 data channel. The read
* and write cmd/data share the same register (data register).
*
* If a command has write and read transaction, you cannot do write
* this time and then do read on next time.
*
* A command writes first with a read response must indicating
* the read length in write operation. Hence the write action must
* be stored temporary and wait until the next read action has been
* arrived. Then we flush the write and read action out together.
*/
if (!dout) {
if (op_nextime == 1) {
/* flags should be SPI_XFER_END, value is 2 */
op_nextime = 0;
andes_spi_write(slave, tmp_wlen, len, tmp_cmd, flags);
}
return andes_spi_read(slave, len, din, flags);
} else if (!din) {
if (flags == SPI_XFER_BEGIN) {
/* store the write command and do operation next time */
op_nextime = 1;
memset(tmp_cmd, 0, sizeof(tmp_cmd));
memcpy(tmp_cmd, dout, len);
debug("%s: tmp_cmd: ", __func__);
for (i = 0; i < len; i++)
debug("%x ", *(tmp_cmd + i));
debug("\n");
tmp_wlen = len;
} else {
/*
* flags should be (SPI_XFER_BEGIN | SPI_XFER_END),
* the value is 3.
*/
if (op_nextime == 1) {
/* flags should be SPI_XFER_END, value is 2 */
op_nextime = 0;
/* flags 3 implies write only */
andes_spi_write(slave, tmp_wlen, 0, tmp_cmd, 3);
}
debug("flags: %x\n", flags);
return andes_spi_write(slave, len, 0, dout, flags);
}
}
out:
return 0;
}
int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
return bus == 0 && cs == 0;
}
void spi_cs_activate(struct spi_slave *slave)
{
/* do nothing */
}
void spi_cs_deactivate(struct spi_slave *slave)
{
/* do nothing */
}