/*
* Copyright (C) 2014-2016 Rafał Miłecki <rafal@milecki.pl>
*
* 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.
*/
#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? */
#define BCM53XXSPI_FLASH_WINDOW SZ_32M
/* The longest observed required wait was 19 ms */
#define BCM53XXSPI_SPE_TIMEOUT_MS 80
struct bcm53xxspi {
struct bcma_device *core;
struct spi_master *master;
void __iomem *mmio_base;
size_t read_offset;
bool bspi; /* Boot SPI mode with memory mapping */
};
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 void bcm53xxspi_disable_bspi(struct bcm53xxspi *b53spi)
{
struct device *dev = &b53spi->core->dev;
unsigned long deadline;
u32 tmp;
if (!b53spi->bspi)
return;
tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);
if (tmp & 0x1)
return;
deadline = jiffies + usecs_to_jiffies(200);
do {
tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_BUSY_STATUS);
if (!(tmp & 0x1)) {
bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL,
0x1);
ndelay(200);
b53spi->bspi = false;
return;
}
udelay(1);
} while (!time_after_eq(jiffies, deadline));
dev_warn(dev, "Timeout disabling BSPI\n");
}
static void bcm53xxspi_enable_bspi(struct bcm53xxspi *b53spi)
{
u32 tmp;
if (b53spi->bspi)
return;
tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);
if (!(tmp & 0x1))
return;
bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL, 0x0);
b53spi->bspi = true;
}
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 + msecs_to_jiffies(BCM53XXSPI_SPE_TIMEOUT_MS);
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 + msecs_to_jiffies(timeout_ms);
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;
bcm53xxspi_disable_bspi(b53spi);
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;
}
static int bcm53xxspi_flash_read(struct spi_device *spi,
struct spi_flash_read_message *msg)
{
struct bcm53xxspi *b53spi = spi_master_get_devdata(spi->master);
int ret = 0;
if (msg->from + msg->len > BCM53XXSPI_FLASH_WINDOW)
return -EINVAL;
bcm53xxspi_enable_bspi(b53spi);
memcpy_fromio(msg->buf, b53spi->mmio_base + msg->from, msg->len);
msg->retlen = msg->len;
return ret;
}
/**************************************************
* BCMA
**************************************************/
static const struct bcma_device_id bcm53xxspi_bcma_tbl[] = {
BCMA_CORE(BCMA_MANUF_BCM, BCMA_CORE_NS_QSPI, BCMA_ANY_REV, BCMA_ANY_CLASS),
{},
};
MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl);
static int bcm53xxspi_bcma_probe(struct bcma_device *core)
{
struct device *dev = &core->dev;
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(dev, sizeof(*b53spi));
if (!master)
return -ENOMEM;
b53spi = spi_master_get_devdata(master);
b53spi->master = master;
b53spi->core = core;
if (core->addr_s[0])
b53spi->mmio_base = devm_ioremap(dev, core->addr_s[0],
BCM53XXSPI_FLASH_WINDOW);
b53spi->bspi = true;
bcm53xxspi_disable_bspi(b53spi);
master->dev.of_node = dev->of_node;
master->transfer_one = bcm53xxspi_transfer_one;
if (b53spi->mmio_base)
master->spi_flash_read = bcm53xxspi_flash_read;
bcma_set_drvdata(core, b53spi);
err = devm_spi_register_master(dev, master);
if (err) {
spi_master_put(master);
bcma_set_drvdata(core, NULL);
return err;
}
return 0;
}
static struct bcma_driver bcm53xxspi_bcma_driver = {
.name = KBUILD_MODNAME,
.id_table = bcm53xxspi_bcma_tbl,
.probe = bcm53xxspi_bcma_probe,
};
/**************************************************
* 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 v2");