linux/drivers/spi/spi-bcm53xx.c

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/bcma/bcma.h>
#include <linux/spi/spi.h>
#include "spi-bcm53xx.h"
#define BCM53XXSPI_MAX_SPI_BAUD 13500000 /* 216 MHz? */
/* The longest observed required wait was 19 ms */
#define BCM53XXSPI_SPE_TIMEOUT_MS 80
struct bcm53xxspi {
struct bcma_device *core;
struct spi_master *master;
size_t read_offset;
};
static inline u32 bcm53xxspi_read(struct bcm53xxspi *b53spi, u16 offset)
{
return bcma_read32(b53spi->core, offset);
}
static inline void bcm53xxspi_write(struct bcm53xxspi *b53spi, u16 offset,
u32 value)
{
bcma_write32(b53spi->core, offset, value);
}
static inline unsigned int bcm53xxspi_calc_timeout(size_t len)
{
/* Do some magic calculation based on length and buad. Add 10% and 1. */
return (len * 9000 / BCM53XXSPI_MAX_SPI_BAUD * 110 / 100) + 1;
}
static int bcm53xxspi_wait(struct bcm53xxspi *b53spi, unsigned int timeout_ms)
{
unsigned long deadline;
u32 tmp;
/* SPE bit has to be 0 before we read MSPI STATUS */
deadline = jiffies + BCM53XXSPI_SPE_TIMEOUT_MS * HZ / 1000;
do {
tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
if (!(tmp & B53SPI_MSPI_SPCR2_SPE))
break;
udelay(5);
} while (!time_after_eq(jiffies, deadline));
if (tmp & B53SPI_MSPI_SPCR2_SPE)
goto spi_timeout;
/* Check status */
deadline = jiffies + timeout_ms * HZ / 1000;
do {
tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_MSPI_STATUS);
if (tmp & B53SPI_MSPI_MSPI_STATUS_SPIF) {
bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0);
return 0;
}
cpu_relax();
udelay(100);
} while (!time_after_eq(jiffies, deadline));
spi_timeout:
bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0);
pr_err("Timeout waiting for SPI to be ready!\n");
return -EBUSY;
}
static void bcm53xxspi_buf_write(struct bcm53xxspi *b53spi, u8 *w_buf,
size_t len, bool cont)
{
u32 tmp;
int i;
for (i = 0; i < len; i++) {
/* Transmit Register File MSB */
bcm53xxspi_write(b53spi, B53SPI_MSPI_TXRAM + 4 * (i * 2),
(unsigned int)w_buf[i]);
}
for (i = 0; i < len; i++) {
tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL |
B53SPI_CDRAM_PCS_DSCK;
if (!cont && i == len - 1)
tmp &= ~B53SPI_CDRAM_CONT;
tmp &= ~0x1;
/* Command Register File */
bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp);
}
/* Set queue pointers */
bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0);
bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP, len - 1);
if (cont)
bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1);
/* Start SPI transfer */
tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
tmp |= B53SPI_MSPI_SPCR2_SPE;
if (cont)
tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD;
bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp);
/* Wait for SPI to finish */
bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len));
if (!cont)
bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0);
b53spi->read_offset = len;
}
static void bcm53xxspi_buf_read(struct bcm53xxspi *b53spi, u8 *r_buf,
size_t len, bool cont)
{
u32 tmp;
int i;
for (i = 0; i < b53spi->read_offset + len; i++) {
tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL |
B53SPI_CDRAM_PCS_DSCK;
if (!cont && i == b53spi->read_offset + len - 1)
tmp &= ~B53SPI_CDRAM_CONT;
tmp &= ~0x1;
/* Command Register File */
bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp);
}
/* Set queue pointers */
bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0);
bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP,
b53spi->read_offset + len - 1);
if (cont)
bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1);
/* Start SPI transfer */
tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
tmp |= B53SPI_MSPI_SPCR2_SPE;
if (cont)
tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD;
bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp);
/* Wait for SPI to finish */
bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len));
if (!cont)
bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0);
for (i = 0; i < len; ++i) {
int offset = b53spi->read_offset + i;
/* Data stored in the transmit register file LSB */
r_buf[i] = (u8)bcm53xxspi_read(b53spi, B53SPI_MSPI_RXRAM + 4 * (1 + offset * 2));
}
b53spi->read_offset = 0;
}
static int bcm53xxspi_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *t)
{
struct bcm53xxspi *b53spi = spi_master_get_devdata(master);
u8 *buf;
size_t left;
if (t->tx_buf) {
buf = (u8 *)t->tx_buf;
left = t->len;
while (left) {
size_t to_write = min_t(size_t, 16, left);
bool cont = left - to_write > 0;
bcm53xxspi_buf_write(b53spi, buf, to_write, cont);
left -= to_write;
buf += to_write;
}
}
if (t->rx_buf) {
buf = (u8 *)t->rx_buf;
left = t->len;
while (left) {
size_t to_read = min_t(size_t, 16 - b53spi->read_offset,
left);
bool cont = left - to_read > 0;
bcm53xxspi_buf_read(b53spi, buf, to_read, cont);
left -= to_read;
buf += to_read;
}
}
return 0;
}
/**************************************************
* BCMA
**************************************************/
static struct spi_board_info bcm53xx_info = {
.modalias = "bcm53xxspiflash",
};
static const struct bcma_device_id bcm53xxspi_bcma_tbl[] = {
BCMA_CORE(BCMA_MANUF_BCM, BCMA_CORE_NS_QSPI, BCMA_ANY_REV, BCMA_ANY_CLASS),
BCMA_CORETABLE_END
};
MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl);
static int bcm53xxspi_bcma_probe(struct bcma_device *core)
{
struct bcm53xxspi *b53spi;
struct spi_master *master;
int err;
if (core->bus->drv_cc.core->id.rev != 42) {
pr_err("SPI on SoC with unsupported ChipCommon rev\n");
return -ENOTSUPP;
}
master = spi_alloc_master(&core->dev, sizeof(*b53spi));
if (!master)
return -ENOMEM;
b53spi = spi_master_get_devdata(master);
b53spi->master = master;
b53spi->core = core;
master->transfer_one = bcm53xxspi_transfer_one;
bcma_set_drvdata(core, b53spi);
err = devm_spi_register_master(&core->dev, master);
if (err) {
spi_master_put(master);
bcma_set_drvdata(core, NULL);
goto out;
}
/* Broadcom SoCs (at least with the CC rev 42) use SPI for flash only */
spi_new_device(master, &bcm53xx_info);
out:
return err;
}
static void bcm53xxspi_bcma_remove(struct bcma_device *core)
{
struct bcm53xxspi *b53spi = bcma_get_drvdata(core);
spi_unregister_master(b53spi->master);
}
static struct bcma_driver bcm53xxspi_bcma_driver = {
.name = KBUILD_MODNAME,
.id_table = bcm53xxspi_bcma_tbl,
.probe = bcm53xxspi_bcma_probe,
.remove = bcm53xxspi_bcma_remove,
};
/**************************************************
* Init & exit
**************************************************/
static int __init bcm53xxspi_module_init(void)
{
int err = 0;
err = bcma_driver_register(&bcm53xxspi_bcma_driver);
if (err)
pr_err("Failed to register bcma driver: %d\n", err);
return err;
}
static void __exit bcm53xxspi_module_exit(void)
{
bcma_driver_unregister(&bcm53xxspi_bcma_driver);
}
module_init(bcm53xxspi_module_init);
module_exit(bcm53xxspi_module_exit);
MODULE_DESCRIPTION("Broadcom BCM53xx SPI Controller driver");
MODULE_AUTHOR("Rafał Miłecki <zajec5@gmail.com>");
MODULE_LICENSE("GPL");