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linux/drivers/spi/spi-falcon.c

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/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* Copyright (C) 2012 Thomas Langer <thomas.langer@lantiq.com>
*/
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <lantiq_soc.h>
#define DRV_NAME "sflash-falcon"
#define FALCON_SPI_XFER_BEGIN (1 << 0)
#define FALCON_SPI_XFER_END (1 << 1)
/* Bus Read Configuration Register0 */
#define BUSRCON0 0x00000010
/* Bus Write Configuration Register0 */
#define BUSWCON0 0x00000018
/* Serial Flash Configuration Register */
#define SFCON 0x00000080
/* Serial Flash Time Register */
#define SFTIME 0x00000084
/* Serial Flash Status Register */
#define SFSTAT 0x00000088
/* Serial Flash Command Register */
#define SFCMD 0x0000008C
/* Serial Flash Address Register */
#define SFADDR 0x00000090
/* Serial Flash Data Register */
#define SFDATA 0x00000094
/* Serial Flash I/O Control Register */
#define SFIO 0x00000098
/* EBU Clock Control Register */
#define EBUCC 0x000000C4
/* Dummy Phase Length */
#define SFCMD_DUMLEN_OFFSET 16
#define SFCMD_DUMLEN_MASK 0x000F0000
/* Chip Select */
#define SFCMD_CS_OFFSET 24
#define SFCMD_CS_MASK 0x07000000
/* field offset */
#define SFCMD_ALEN_OFFSET 20
#define SFCMD_ALEN_MASK 0x00700000
/* SCK Rise-edge Position */
#define SFTIME_SCKR_POS_OFFSET 8
#define SFTIME_SCKR_POS_MASK 0x00000F00
/* SCK Period */
#define SFTIME_SCK_PER_OFFSET 0
#define SFTIME_SCK_PER_MASK 0x0000000F
/* SCK Fall-edge Position */
#define SFTIME_SCKF_POS_OFFSET 12
#define SFTIME_SCKF_POS_MASK 0x0000F000
/* Device Size */
#define SFCON_DEV_SIZE_A23_0 0x03000000
#define SFCON_DEV_SIZE_MASK 0x0F000000
/* Read Data Position */
#define SFTIME_RD_POS_MASK 0x000F0000
/* Data Output */
#define SFIO_UNUSED_WD_MASK 0x0000000F
/* Command Opcode mask */
#define SFCMD_OPC_MASK 0x000000FF
/* dlen bytes of data to write */
#define SFCMD_DIR_WRITE 0x00000100
/* Data Length offset */
#define SFCMD_DLEN_OFFSET 9
/* Command Error */
#define SFSTAT_CMD_ERR 0x20000000
/* Access Command Pending */
#define SFSTAT_CMD_PEND 0x00400000
/* Frequency set to 100MHz. */
#define EBUCC_EBUDIV_SELF100 0x00000001
/* Serial Flash */
#define BUSRCON0_AGEN_SERIAL_FLASH 0xF0000000
/* 8-bit multiplexed */
#define BUSRCON0_PORTW_8_BIT_MUX 0x00000000
/* Serial Flash */
#define BUSWCON0_AGEN_SERIAL_FLASH 0xF0000000
/* Chip Select after opcode */
#define SFCMD_KEEP_CS_KEEP_SELECTED 0x00008000
#define CLOCK_100M 100000000
#define CLOCK_50M 50000000
struct falcon_sflash {
u32 sfcmd; /* for caching of opcode, direction, ... */
struct spi_master *master;
};
int falcon_sflash_xfer(struct spi_device *spi, struct spi_transfer *t,
unsigned long flags)
{
struct device *dev = &spi->dev;
struct falcon_sflash *priv = spi_master_get_devdata(spi->master);
const u8 *txp = t->tx_buf;
u8 *rxp = t->rx_buf;
unsigned int bytelen = ((8 * t->len + 7) / 8);
unsigned int len, alen, dumlen;
u32 val;
enum {
state_init,
state_command_prepare,
state_write,
state_read,
state_disable_cs,
state_end
} state = state_init;
do {
switch (state) {
case state_init: /* detect phase of upper layer sequence */
{
/* initial write ? */
if (flags & FALCON_SPI_XFER_BEGIN) {
if (!txp) {
dev_err(dev,
"BEGIN without tx data!\n");
return -ENODATA;
}
/*
* Prepare the parts of the sfcmd register,
* which should not change during a sequence!
* Only exception are the length fields,
* especially alen and dumlen.
*/
priv->sfcmd = ((spi->chip_select
<< SFCMD_CS_OFFSET)
& SFCMD_CS_MASK);
priv->sfcmd |= SFCMD_KEEP_CS_KEEP_SELECTED;
priv->sfcmd |= *txp;
txp++;
bytelen--;
if (bytelen) {
/*
* more data:
* maybe address and/or dummy
*/
state = state_command_prepare;
break;
} else {
dev_dbg(dev, "write cmd %02X\n",
priv->sfcmd & SFCMD_OPC_MASK);
}
}
/* continued write ? */
if (txp && bytelen) {
state = state_write;
break;
}
/* read data? */
if (rxp && bytelen) {
state = state_read;
break;
}
/* end of sequence? */
if (flags & FALCON_SPI_XFER_END)
state = state_disable_cs;
else
state = state_end;
break;
}
/* collect tx data for address and dummy phase */
case state_command_prepare:
{
/* txp is valid, already checked */
val = 0;
alen = 0;
dumlen = 0;
while (bytelen > 0) {
if (alen < 3) {
val = (val << 8) | (*txp++);
alen++;
} else if ((dumlen < 15) && (*txp == 0)) {
/*
* assume dummy bytes are set to 0
* from upper layer
*/
dumlen++;
txp++;
} else {
break;
}
bytelen--;
}
priv->sfcmd &= ~(SFCMD_ALEN_MASK | SFCMD_DUMLEN_MASK);
priv->sfcmd |= (alen << SFCMD_ALEN_OFFSET) |
(dumlen << SFCMD_DUMLEN_OFFSET);
if (alen > 0)
ltq_ebu_w32(val, SFADDR);
dev_dbg(dev, "wr %02X, alen=%d (addr=%06X) dlen=%d\n",
priv->sfcmd & SFCMD_OPC_MASK,
alen, val, dumlen);
if (bytelen > 0) {
/* continue with write */
state = state_write;
} else if (flags & FALCON_SPI_XFER_END) {
/* end of sequence? */
state = state_disable_cs;
} else {
/*
* go to end and expect another
* call (read or write)
*/
state = state_end;
}
break;
}
case state_write:
{
/* txp still valid */
priv->sfcmd |= SFCMD_DIR_WRITE;
len = 0;
val = 0;
do {
if (bytelen--)
val |= (*txp++) << (8 * len++);
if ((flags & FALCON_SPI_XFER_END)
&& (bytelen == 0)) {
priv->sfcmd &=
~SFCMD_KEEP_CS_KEEP_SELECTED;
}
if ((len == 4) || (bytelen == 0)) {
ltq_ebu_w32(val, SFDATA);
ltq_ebu_w32(priv->sfcmd
| (len<<SFCMD_DLEN_OFFSET),
SFCMD);
len = 0;
val = 0;
priv->sfcmd &= ~(SFCMD_ALEN_MASK
| SFCMD_DUMLEN_MASK);
}
} while (bytelen);
state = state_end;
break;
}
case state_read:
{
/* read data */
priv->sfcmd &= ~SFCMD_DIR_WRITE;
do {
if ((flags & FALCON_SPI_XFER_END)
&& (bytelen <= 4)) {
priv->sfcmd &=
~SFCMD_KEEP_CS_KEEP_SELECTED;
}
len = (bytelen > 4) ? 4 : bytelen;
bytelen -= len;
ltq_ebu_w32(priv->sfcmd
| (len << SFCMD_DLEN_OFFSET), SFCMD);
priv->sfcmd &= ~(SFCMD_ALEN_MASK
| SFCMD_DUMLEN_MASK);
do {
val = ltq_ebu_r32(SFSTAT);
if (val & SFSTAT_CMD_ERR) {
/* reset error status */
dev_err(dev, "SFSTAT: CMD_ERR");
dev_err(dev, " (%x)\n", val);
ltq_ebu_w32(SFSTAT_CMD_ERR,
SFSTAT);
return -EBADE;
}
} while (val & SFSTAT_CMD_PEND);
val = ltq_ebu_r32(SFDATA);
do {
*rxp = (val & 0xFF);
rxp++;
val >>= 8;
len--;
} while (len);
} while (bytelen);
state = state_end;
break;
}
case state_disable_cs:
{
priv->sfcmd &= ~SFCMD_KEEP_CS_KEEP_SELECTED;
ltq_ebu_w32(priv->sfcmd | (0 << SFCMD_DLEN_OFFSET),
SFCMD);
val = ltq_ebu_r32(SFSTAT);
if (val & SFSTAT_CMD_ERR) {
/* reset error status */
dev_err(dev, "SFSTAT: CMD_ERR (%x)\n", val);
ltq_ebu_w32(SFSTAT_CMD_ERR, SFSTAT);
return -EBADE;
}
state = state_end;
break;
}
case state_end:
break;
}
} while (state != state_end);
return 0;
}
static int falcon_sflash_setup(struct spi_device *spi)
{
unsigned int i;
unsigned long flags;
spin_lock_irqsave(&ebu_lock, flags);
if (spi->max_speed_hz >= CLOCK_100M) {
/* set EBU clock to 100 MHz */
ltq_sys1_w32_mask(0, EBUCC_EBUDIV_SELF100, EBUCC);
i = 1; /* divider */
} else {
/* set EBU clock to 50 MHz */
ltq_sys1_w32_mask(EBUCC_EBUDIV_SELF100, 0, EBUCC);
/* search for suitable divider */
for (i = 1; i < 7; i++) {
if (CLOCK_50M / i <= spi->max_speed_hz)
break;
}
}
/* setup period of serial clock */
ltq_ebu_w32_mask(SFTIME_SCKF_POS_MASK
| SFTIME_SCKR_POS_MASK
| SFTIME_SCK_PER_MASK,
(i << SFTIME_SCKR_POS_OFFSET)
| (i << (SFTIME_SCK_PER_OFFSET + 1)),
SFTIME);
/*
* set some bits of unused_wd, to not trigger HOLD/WP
* signals on non QUAD flashes
*/
ltq_ebu_w32((SFIO_UNUSED_WD_MASK & (0x8 | 0x4)), SFIO);
ltq_ebu_w32(BUSRCON0_AGEN_SERIAL_FLASH | BUSRCON0_PORTW_8_BIT_MUX,
BUSRCON0);
ltq_ebu_w32(BUSWCON0_AGEN_SERIAL_FLASH, BUSWCON0);
/* set address wrap around to maximum for 24-bit addresses */
ltq_ebu_w32_mask(SFCON_DEV_SIZE_MASK, SFCON_DEV_SIZE_A23_0, SFCON);
spin_unlock_irqrestore(&ebu_lock, flags);
return 0;
}
static int falcon_sflash_xfer_one(struct spi_master *master,
struct spi_message *m)
{
struct falcon_sflash *priv = spi_master_get_devdata(master);
struct spi_transfer *t;
unsigned long spi_flags;
unsigned long flags;
int ret = 0;
priv->sfcmd = 0;
m->actual_length = 0;
spi_flags = FALCON_SPI_XFER_BEGIN;
list_for_each_entry(t, &m->transfers, transfer_list) {
if (list_is_last(&t->transfer_list, &m->transfers))
spi_flags |= FALCON_SPI_XFER_END;
spin_lock_irqsave(&ebu_lock, flags);
ret = falcon_sflash_xfer(m->spi, t, spi_flags);
spin_unlock_irqrestore(&ebu_lock, flags);
if (ret)
break;
m->actual_length += t->len;
WARN_ON(t->delay_usecs || t->cs_change);
spi_flags = 0;
}
m->status = ret;
spi_finalize_current_message(master);
return 0;
}
static int falcon_sflash_probe(struct platform_device *pdev)
{
struct falcon_sflash *priv;
struct spi_master *master;
int ret;
if (ltq_boot_select() != BS_SPI) {
dev_err(&pdev->dev, "invalid bootstrap options\n");
return -ENODEV;
}
master = spi_alloc_master(&pdev->dev, sizeof(*priv));
if (!master)
return -ENOMEM;
priv = spi_master_get_devdata(master);
priv->master = master;
master->mode_bits = SPI_MODE_3;
master->flags = SPI_MASTER_HALF_DUPLEX;
master->setup = falcon_sflash_setup;
master->transfer_one_message = falcon_sflash_xfer_one;
master->dev.of_node = pdev->dev.of_node;
ret = devm_spi_register_master(&pdev->dev, master);
if (ret)
spi_master_put(master);
return ret;
}
static const struct of_device_id falcon_sflash_match[] = {
{ .compatible = "lantiq,sflash-falcon" },
{},
};
MODULE_DEVICE_TABLE(of, falcon_sflash_match);
static struct platform_driver falcon_sflash_driver = {
.probe = falcon_sflash_probe,
.driver = {
.name = DRV_NAME,
.of_match_table = falcon_sflash_match,
}
};
module_platform_driver(falcon_sflash_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Lantiq Falcon SPI/SFLASH controller driver");
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