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linux/drivers/net/wireless/wl12xx/spi.c
Ido Yariv 2da69b890f wl12xx: Switch to level trigger interrupts 
The interrupt of the wl12xx is a level interrupt in nature, since the
interrupt line is not auto-reset. However, since resetting the interrupt
requires bus transactions, this cannot be done from an interrupt
context. Thus, requesting a level interrupt would require to disable the
irq and re-enable it after the HW is acknowledged. Since we now request
a threaded irq, this can also be done by specifying the IRQF_ONESHOT
flag.

Triggering on an edge can be problematic in some platforms, if the
sampling frequency is not sufficient for detecting very frequent
interrupts. In case an interrupt is missed, the driver will hang as the
interrupt line will stay high until it is acknowledged by the driver,
which will never happen.

Fix this by requesting a level triggered interrupt, with the
IRQF_ONESHOT flag.

Signed-off-by: Ido Yariv <ido@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>
2011-03-03 16:10:46 +02:00

495 lines
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/*
* This file is part of wl1271
*
* Copyright (C) 2008-2009 Nokia Corporation
*
* Contact: Luciano Coelho <luciano.coelho@nokia.com>
*
* 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.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/crc7.h>
#include <linux/spi/spi.h>
#include <linux/wl12xx.h>
#include <linux/slab.h>
#include "wl12xx.h"
#include "wl12xx_80211.h"
#include "io.h"
#include "reg.h"
#define WSPI_CMD_READ 0x40000000
#define WSPI_CMD_WRITE 0x00000000
#define WSPI_CMD_FIXED 0x20000000
#define WSPI_CMD_BYTE_LENGTH 0x1FFE0000
#define WSPI_CMD_BYTE_LENGTH_OFFSET 17
#define WSPI_CMD_BYTE_ADDR 0x0001FFFF
#define WSPI_INIT_CMD_CRC_LEN 5
#define WSPI_INIT_CMD_START 0x00
#define WSPI_INIT_CMD_TX 0x40
/* the extra bypass bit is sampled by the TNET as '1' */
#define WSPI_INIT_CMD_BYPASS_BIT 0x80
#define WSPI_INIT_CMD_FIXEDBUSY_LEN 0x07
#define WSPI_INIT_CMD_EN_FIXEDBUSY 0x80
#define WSPI_INIT_CMD_DIS_FIXEDBUSY 0x00
#define WSPI_INIT_CMD_IOD 0x40
#define WSPI_INIT_CMD_IP 0x20
#define WSPI_INIT_CMD_CS 0x10
#define WSPI_INIT_CMD_WS 0x08
#define WSPI_INIT_CMD_WSPI 0x01
#define WSPI_INIT_CMD_END 0x01
#define WSPI_INIT_CMD_LEN 8
#define HW_ACCESS_WSPI_FIXED_BUSY_LEN \
((WL1271_BUSY_WORD_LEN - 4) / sizeof(u32))
#define HW_ACCESS_WSPI_INIT_CMD_MASK 0
/* HW limitation: maximum possible chunk size is 4095 bytes */
#define WSPI_MAX_CHUNK_SIZE 4092
#define WSPI_MAX_NUM_OF_CHUNKS (WL1271_AGGR_BUFFER_SIZE / WSPI_MAX_CHUNK_SIZE)
static inline struct spi_device *wl_to_spi(struct wl1271 *wl)
{
return wl->if_priv;
}
static struct device *wl1271_spi_wl_to_dev(struct wl1271 *wl)
{
return &(wl_to_spi(wl)->dev);
}
static void wl1271_spi_disable_interrupts(struct wl1271 *wl)
{
disable_irq(wl->irq);
}
static void wl1271_spi_enable_interrupts(struct wl1271 *wl)
{
enable_irq(wl->irq);
}
static void wl1271_spi_reset(struct wl1271 *wl)
{
u8 *cmd;
struct spi_transfer t;
struct spi_message m;
cmd = kzalloc(WSPI_INIT_CMD_LEN, GFP_KERNEL);
if (!cmd) {
wl1271_error("could not allocate cmd for spi reset");
return;
}
memset(&t, 0, sizeof(t));
spi_message_init(&m);
memset(cmd, 0xff, WSPI_INIT_CMD_LEN);
t.tx_buf = cmd;
t.len = WSPI_INIT_CMD_LEN;
spi_message_add_tail(&t, &m);
spi_sync(wl_to_spi(wl), &m);
wl1271_dump(DEBUG_SPI, "spi reset -> ", cmd, WSPI_INIT_CMD_LEN);
kfree(cmd);
}
static void wl1271_spi_init(struct wl1271 *wl)
{
u8 crc[WSPI_INIT_CMD_CRC_LEN], *cmd;
struct spi_transfer t;
struct spi_message m;
cmd = kzalloc(WSPI_INIT_CMD_LEN, GFP_KERNEL);
if (!cmd) {
wl1271_error("could not allocate cmd for spi init");
return;
}
memset(crc, 0, sizeof(crc));
memset(&t, 0, sizeof(t));
spi_message_init(&m);
/*
* Set WSPI_INIT_COMMAND
* the data is being send from the MSB to LSB
*/
cmd[2] = 0xff;
cmd[3] = 0xff;
cmd[1] = WSPI_INIT_CMD_START | WSPI_INIT_CMD_TX;
cmd[0] = 0;
cmd[7] = 0;
cmd[6] |= HW_ACCESS_WSPI_INIT_CMD_MASK << 3;
cmd[6] |= HW_ACCESS_WSPI_FIXED_BUSY_LEN & WSPI_INIT_CMD_FIXEDBUSY_LEN;
if (HW_ACCESS_WSPI_FIXED_BUSY_LEN == 0)
cmd[5] |= WSPI_INIT_CMD_DIS_FIXEDBUSY;
else
cmd[5] |= WSPI_INIT_CMD_EN_FIXEDBUSY;
cmd[5] |= WSPI_INIT_CMD_IOD | WSPI_INIT_CMD_IP | WSPI_INIT_CMD_CS
| WSPI_INIT_CMD_WSPI | WSPI_INIT_CMD_WS;
crc[0] = cmd[1];
crc[1] = cmd[0];
crc[2] = cmd[7];
crc[3] = cmd[6];
crc[4] = cmd[5];
cmd[4] |= crc7(0, crc, WSPI_INIT_CMD_CRC_LEN) << 1;
cmd[4] |= WSPI_INIT_CMD_END;
t.tx_buf = cmd;
t.len = WSPI_INIT_CMD_LEN;
spi_message_add_tail(&t, &m);
spi_sync(wl_to_spi(wl), &m);
wl1271_dump(DEBUG_SPI, "spi init -> ", cmd, WSPI_INIT_CMD_LEN);
kfree(cmd);
}
#define WL1271_BUSY_WORD_TIMEOUT 1000
static int wl1271_spi_read_busy(struct wl1271 *wl)
{
struct spi_transfer t[1];
struct spi_message m;
u32 *busy_buf;
int num_busy_bytes = 0;
/*
* Read further busy words from SPI until a non-busy word is
* encountered, then read the data itself into the buffer.
*/
num_busy_bytes = WL1271_BUSY_WORD_TIMEOUT;
busy_buf = wl->buffer_busyword;
while (num_busy_bytes) {
num_busy_bytes--;
spi_message_init(&m);
memset(t, 0, sizeof(t));
t[0].rx_buf = busy_buf;
t[0].len = sizeof(u32);
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);
spi_sync(wl_to_spi(wl), &m);
if (*busy_buf & 0x1)
return 0;
}
/* The SPI bus is unresponsive, the read failed. */
wl1271_error("SPI read busy-word timeout!\n");
return -ETIMEDOUT;
}
static void wl1271_spi_raw_read(struct wl1271 *wl, int addr, void *buf,
size_t len, bool fixed)
{
struct spi_transfer t[2];
struct spi_message m;
u32 *busy_buf;
u32 *cmd;
u32 chunk_len;
while (len > 0) {
chunk_len = min((size_t)WSPI_MAX_CHUNK_SIZE, len);
cmd = &wl->buffer_cmd;
busy_buf = wl->buffer_busyword;
*cmd = 0;
*cmd |= WSPI_CMD_READ;
*cmd |= (chunk_len << WSPI_CMD_BYTE_LENGTH_OFFSET) &
WSPI_CMD_BYTE_LENGTH;
*cmd |= addr & WSPI_CMD_BYTE_ADDR;
if (fixed)
*cmd |= WSPI_CMD_FIXED;
spi_message_init(&m);
memset(t, 0, sizeof(t));
t[0].tx_buf = cmd;
t[0].len = 4;
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);
/* Busy and non busy words read */
t[1].rx_buf = busy_buf;
t[1].len = WL1271_BUSY_WORD_LEN;
t[1].cs_change = true;
spi_message_add_tail(&t[1], &m);
spi_sync(wl_to_spi(wl), &m);
if (!(busy_buf[WL1271_BUSY_WORD_CNT - 1] & 0x1) &&
wl1271_spi_read_busy(wl)) {
memset(buf, 0, chunk_len);
return;
}
spi_message_init(&m);
memset(t, 0, sizeof(t));
t[0].rx_buf = buf;
t[0].len = chunk_len;
t[0].cs_change = true;
spi_message_add_tail(&t[0], &m);
spi_sync(wl_to_spi(wl), &m);
wl1271_dump(DEBUG_SPI, "spi_read cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_read buf <- ", buf, chunk_len);
if (!fixed)
addr += chunk_len;
buf += chunk_len;
len -= chunk_len;
}
}
static void wl1271_spi_raw_write(struct wl1271 *wl, int addr, void *buf,
size_t len, bool fixed)
{
struct spi_transfer t[2 * WSPI_MAX_NUM_OF_CHUNKS];
struct spi_message m;
u32 commands[WSPI_MAX_NUM_OF_CHUNKS];
u32 *cmd;
u32 chunk_len;
int i;
WARN_ON(len > WL1271_AGGR_BUFFER_SIZE);
spi_message_init(&m);
memset(t, 0, sizeof(t));
cmd = &commands[0];
i = 0;
while (len > 0) {
chunk_len = min((size_t)WSPI_MAX_CHUNK_SIZE, len);
*cmd = 0;
*cmd |= WSPI_CMD_WRITE;
*cmd |= (chunk_len << WSPI_CMD_BYTE_LENGTH_OFFSET) &
WSPI_CMD_BYTE_LENGTH;
*cmd |= addr & WSPI_CMD_BYTE_ADDR;
if (fixed)
*cmd |= WSPI_CMD_FIXED;
t[i].tx_buf = cmd;
t[i].len = sizeof(*cmd);
spi_message_add_tail(&t[i++], &m);
t[i].tx_buf = buf;
t[i].len = chunk_len;
spi_message_add_tail(&t[i++], &m);
wl1271_dump(DEBUG_SPI, "spi_write cmd -> ", cmd, sizeof(*cmd));
wl1271_dump(DEBUG_SPI, "spi_write buf -> ", buf, chunk_len);
if (!fixed)
addr += chunk_len;
buf += chunk_len;
len -= chunk_len;
cmd++;
}
spi_sync(wl_to_spi(wl), &m);
}
static irqreturn_t wl1271_hardirq(int irq, void *cookie)
{
struct wl1271 *wl = cookie;
unsigned long flags;
wl1271_debug(DEBUG_IRQ, "IRQ");
/* complete the ELP completion */
spin_lock_irqsave(&wl->wl_lock, flags);
set_bit(WL1271_FLAG_IRQ_RUNNING, &wl->flags);
if (wl->elp_compl) {
complete(wl->elp_compl);
wl->elp_compl = NULL;
}
spin_unlock_irqrestore(&wl->wl_lock, flags);
return IRQ_WAKE_THREAD;
}
static int wl1271_spi_set_power(struct wl1271 *wl, bool enable)
{
if (wl->set_power)
wl->set_power(enable);
return 0;
}
static struct wl1271_if_operations spi_ops = {
.read = wl1271_spi_raw_read,
.write = wl1271_spi_raw_write,
.reset = wl1271_spi_reset,
.init = wl1271_spi_init,
.power = wl1271_spi_set_power,
.dev = wl1271_spi_wl_to_dev,
.enable_irq = wl1271_spi_enable_interrupts,
.disable_irq = wl1271_spi_disable_interrupts
};
static int __devinit wl1271_probe(struct spi_device *spi)
{
struct wl12xx_platform_data *pdata;
struct ieee80211_hw *hw;
struct wl1271 *wl;
int ret;
pdata = spi->dev.platform_data;
if (!pdata) {
wl1271_error("no platform data");
return -ENODEV;
}
hw = wl1271_alloc_hw();
if (IS_ERR(hw))
return PTR_ERR(hw);
wl = hw->priv;
dev_set_drvdata(&spi->dev, wl);
wl->if_priv = spi;
wl->if_ops = &spi_ops;
/* This is the only SPI value that we need to set here, the rest
* comes from the board-peripherals file */
spi->bits_per_word = 32;
ret = spi_setup(spi);
if (ret < 0) {
wl1271_error("spi_setup failed");
goto out_free;
}
wl->set_power = pdata->set_power;
if (!wl->set_power) {
wl1271_error("set power function missing in platform data");
ret = -ENODEV;
goto out_free;
}
wl->ref_clock = pdata->board_ref_clock;
wl->irq = spi->irq;
if (wl->irq < 0) {
wl1271_error("irq missing in platform data");
ret = -ENODEV;
goto out_free;
}
ret = request_threaded_irq(wl->irq, wl1271_hardirq, wl1271_irq,
IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
DRIVER_NAME, wl);
if (ret < 0) {
wl1271_error("request_irq() failed: %d", ret);
goto out_free;
}
disable_irq(wl->irq);
ret = wl1271_init_ieee80211(wl);
if (ret)
goto out_irq;
ret = wl1271_register_hw(wl);
if (ret)
goto out_irq;
wl1271_notice("initialized");
return 0;
out_irq:
free_irq(wl->irq, wl);
out_free:
wl1271_free_hw(wl);
return ret;
}
static int __devexit wl1271_remove(struct spi_device *spi)
{
struct wl1271 *wl = dev_get_drvdata(&spi->dev);
wl1271_unregister_hw(wl);
free_irq(wl->irq, wl);
wl1271_free_hw(wl);
return 0;
}
static struct spi_driver wl1271_spi_driver = {
.driver = {
.name = "wl1271_spi",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = wl1271_probe,
.remove = __devexit_p(wl1271_remove),
};
static int __init wl1271_init(void)
{
int ret;
ret = spi_register_driver(&wl1271_spi_driver);
if (ret < 0) {
wl1271_error("failed to register spi driver: %d", ret);
goto out;
}
out:
return ret;
}
static void __exit wl1271_exit(void)
{
spi_unregister_driver(&wl1271_spi_driver);
wl1271_notice("unloaded");
}
module_init(wl1271_init);
module_exit(wl1271_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
MODULE_AUTHOR("Juuso Oikarinen <juuso.oikarinen@nokia.com>");
MODULE_FIRMWARE(WL1271_FW_NAME);
MODULE_FIRMWARE(WL1271_AP_FW_NAME);
MODULE_ALIAS("spi:wl1271");
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