This is a rather large patch. The older code wasn't stable enough
in all cases as it confused the EC during high system load. The new
code uses a better state machine which is quiet similar to the
original code from NVIDIA.
In short, this introduces:
- new ISR state machine for protocol handling
- a ring buffer for received messages
(this avoids the use of malloc in the ISR)
- the list operations are now protected by spinlocks to
handle concurrent access in the bottom half
- a "nvec" workqueue. The EC is very sensitive regarding
correct timing. In the past, system events often caused
slow responses resulting in a protocol timeout. The new code
avoids this by using its own workqueue.
Things to do:
* the ring buffer code is not finished yet, e.g. the received link
list is just a pointer to the ring buffer array, while it should
be a list of its own.
* error handling is also not finished yet, e.g. during ring buffer
overrun the ec needs to be reseted.
* the locking needs a review.
* the sync_write should return an error code instead of the received
message.
* other things I've forgotten now
Signed-off-by: Marc Dietrich <marvin24@xxxxxx>
---
drivers/staging/nvec/nvec.c | 330 ++++++++++++++++++++++++++-------------
drivers/staging/nvec/nvec.h | 56 ++++----
drivers/staging/nvec/nvec_kbd.c | 2 +-
3 files changed, 254 insertions(+), 134 deletions(-)
diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index 0936c54..62f4b7d 100644
--- a/drivers/staging/nvec/nvec.c
+++ b/drivers/staging/nvec/nvec.c
@@ -91,29 +91,73 @@ static int nvec_status_notifier(struct notifier_block *nb,
void nvec_write_async(struct nvec_chip *nvec, const unsigned char *data,
short size)
{
- struct nvec_msg *msg = kzalloc(sizeof(struct nvec_msg), GFP_NOWAIT);
+ struct nvec_msg *msg;
+ unsigned long flags;
- msg->data = kzalloc(size, GFP_NOWAIT);
+ msg = kzalloc(sizeof(struct nvec_msg), GFP_ATOMIC);
msg->data[0] = size;
memcpy(msg->data + 1, data, size);
msg->size = size + 1;
- msg->pos = 0;
- INIT_LIST_HEAD(&msg->node);
+ spin_lock_irqsave(&nvec->tx_lock, flags);
list_add_tail(&msg->node, &nvec->tx_data);
+ spin_unlock_irqrestore(&nvec->tx_lock, flags);
- gpio_set_value(nvec->gpio, 0);
+ queue_work(nvec->wq, &nvec->tx_work);
}
-
EXPORT_SYMBOL(nvec_write_async);
+struct nvec_msg *nvec_write_sync(struct nvec_chip *nvec,
+ const unsigned char *data, short size)
+{
+ mutex_lock(&nvec->sync_write_mutex);
+
+ nvec->sync_write_pending = (data[1] << 8) + data[0];
+ nvec_write_async(nvec, data, size);
+
+ dev_dbg(nvec->dev, "nvec_sync_write: 0x%04x\n",
+ nvec->sync_write_pending);
+ if (!(wait_for_completion_timeout(&nvec->sync_write,
+ msecs_to_jiffies(2000)))) {
+ dev_warn(nvec->dev, "timeout waiting for sync write to complete\n");
+ mutex_unlock(&nvec->sync_write_mutex);
+ return NULL;
+ }
+
+ dev_dbg(nvec->dev, "nvec_sync_write: pong!\n");
+
+ mutex_unlock(&nvec->sync_write_mutex);
+
+ return nvec->last_sync_msg;
+}
+EXPORT_SYMBOL(nvec_write_sync);
+
+/* TX worker */
static void nvec_request_master(struct work_struct *work)
{
struct nvec_chip *nvec = container_of(work, struct nvec_chip, tx_work);
+ unsigned long flags;
+ struct nvec_msg *msg;
- if (!list_empty(&nvec->tx_data)) {
+ mutex_lock(&nvec->async_write_mutex);
+ spin_lock_irqsave(&nvec->tx_lock, flags);
+ while (!list_empty(&nvec->tx_data)) {
+ msg = list_first_entry(&nvec->tx_data, struct nvec_msg, node);
+ spin_unlock_irqrestore(&nvec->tx_lock, flags);
gpio_set_value(nvec->gpio, 0);
+ if (!(wait_for_completion_interruptible_timeout(
+ &nvec->ec_transfer, msecs_to_jiffies(5000)))) {
+ dev_warn(nvec->dev, "timeout waiting for ec transfer\n");
+ gpio_set_value(nvec->gpio, 1);
+ msg->pos = 0;
+ } else {
+ list_del_init(&msg->node);
+ kfree(msg);
+ }
+ spin_lock_irqsave(&nvec->tx_lock, flags);
}
+ spin_unlock_irqrestore(&nvec->tx_lock, flags);
+ mutex_unlock(&nvec->async_write_mutex);
}
static int parse_msg(struct nvec_chip *nvec, struct nvec_msg *msg)
@@ -135,144 +179,209 @@ static int parse_msg(struct nvec_chip *nvec, struct nvec_msg *msg)
return 0;
}
-static struct nvec_msg *nvec_write_sync(struct nvec_chip *nvec,
- const unsigned char *data, short size)
-{
- down(&nvec->sync_write_mutex);
-
- nvec->sync_write_pending = (data[1] << 8) + data[0];
- nvec_write_async(nvec, data, size);
-
- dev_dbg(nvec->dev, "nvec_sync_write: 0x%04x\n",
- nvec->sync_write_pending);
- wait_for_completion(&nvec->sync_write);
- dev_dbg(nvec->dev, "nvec_sync_write: pong!\n");
-
- up(&nvec->sync_write_mutex);
-
- return nvec->last_sync_msg;
-}
-
/* RX worker */
static void nvec_dispatch(struct work_struct *work)
{
struct nvec_chip *nvec = container_of(work, struct nvec_chip, rx_work);
+ unsigned long flags;
struct nvec_msg *msg;
+ mutex_lock(&nvec->dispatch_mutex);
+ spin_lock_irqsave(&nvec->rx_lock, flags);
while (!list_empty(&nvec->rx_data)) {
msg = list_first_entry(&nvec->rx_data, struct nvec_msg, node);
list_del_init(&msg->node);
+ spin_unlock_irqrestore(&nvec->rx_lock, flags);
if (nvec->sync_write_pending ==
- (msg->data[2] << 8) + msg->data[0]) {
+ (msg->data[2] << 8) + msg->data[0]) {
dev_dbg(nvec->dev, "sync write completed!\n");
nvec->sync_write_pending = 0;
nvec->last_sync_msg = msg;
complete(&nvec->sync_write);
} else {
parse_msg(nvec, msg);
- if ((!msg) || (!msg->data))
- dev_warn(nvec->dev,
- "attempt access zero pointer\n");
- else {
- kfree(msg->data);
- kfree(msg);
- }
+ msg->used = 0;
}
+ spin_lock_irqsave(&nvec->rx_lock, flags);
}
+ spin_unlock_irqrestore(&nvec->rx_lock, flags);
+ mutex_unlock(&nvec->dispatch_mutex);
}
static irqreturn_t nvec_interrupt(int irq, void *dev)
{
unsigned long status;
- unsigned long received;
- unsigned char to_send;
- struct nvec_msg *msg;
+ unsigned long received = 0;
+ unsigned char to_send = 0;
+ unsigned long irq_mask = I2C_SL_IRQ | END_TRANS | RCVD | RNW;
+ unsigned long flags;
+ unsigned long dtime;
+ int valid_proto = 0;
+ int end_trans = 0;
+ struct timespec start_time, end_time, diff_time;
struct nvec_chip *nvec = (struct nvec_chip *)dev;
void __iomem *base = nvec->base;
+ getnstimeofday(&start_time);
+
status = readl(base + I2C_SL_STATUS);
- if (!(status & I2C_SL_IRQ)) {
- dev_warn(nvec->dev, "nvec Spurious IRQ\n");
+ if (!(status & irq_mask) && !((status & ~irq_mask) == 0)) {
+ dev_warn(nvec->dev, "unexpected irq mask %lx\n", status);
goto handled;
}
- if (status & END_TRANS && !(status & RCVD)) {
- nvec->state = NVEC_WAIT;
- if (nvec->rx->size > 1) {
- list_add_tail(&nvec->rx->node, &nvec->rx_data);
- schedule_work(&nvec->rx_work);
- } else {
- kfree(nvec->rx->data);
- kfree(nvec->rx);
- }
- return IRQ_HANDLED;
- } else if (status & RNW) {
- if (status & RCVD)
- udelay(3);
- if (status & RCVD) {
- nvec->state = NVEC_WRITE;
- } else {
-/* dev_dbg(nvec->dev, "Read comm cont !\n"); */
- }
+ if ((status & I2C_SL_IRQ) == 0) {
+ dev_warn(nvec->dev, "Spurious IRQ\n");
+ goto handled;
+ }
+
+ /* just ET (but not ET with new comm [0x1c] !) */
+ if ((status & END_TRANS) && !(status & RCVD))
+ goto handled;
+
+ if (status & RNW) { /* ec reads from slave, status = 0x0a, 0x0e */
+ spin_lock_irqsave(&nvec->tx_lock, flags);
if (list_empty(&nvec->tx_data)) {
- dev_err(nvec->dev, "nvec empty tx - sending no-op\n");
- to_send = 0x8a;
- nvec_write_async(nvec, "\x07\x02", 2);
+ dev_err(nvec->dev, "empty tx - sending no-op\n");
+
+ nvec->tx_scratch.data[0] = 4;
+ nvec->tx_scratch.data[1] = 0x8a;
+ nvec->tx_scratch.data[2] = 0x02;
+ nvec->tx_scratch.data[3] = 0x07;
+ nvec->tx_scratch.data[4] = 0x02;
+
+ nvec->tx_scratch.size = 5;
+ nvec->tx_scratch.pos = 0;
+ nvec->tx = &nvec->tx_scratch;
+ list_add_tail(&nvec->tx->node, &nvec->tx_data);
+ spin_unlock_irqrestore(&nvec->tx_lock, flags);
+ valid_proto = 1;
} else {
- msg =
- list_first_entry(&nvec->tx_data, struct nvec_msg,
- node);
- if (msg->pos < msg->size) {
- to_send = msg->data[msg->pos];
- msg->pos++;
- } else {
- dev_err(nvec->dev, "nvec crap! %d\n",
- msg->size);
- to_send = 0x01;
+ if (status & RCVD) { /* 0x0e, new transfer */
+ nvec->tx = list_first_entry(&nvec->tx_data, struct nvec_msg, node);
+ spin_unlock_irqrestore(&nvec->tx_lock, flags);
+ /* Work around for AP20 New Slave Hw Bug.
+ ((1000 / 80) / 2) + 1 = 33 */
+ getnstimeofday(&end_time);
+ diff_time = timespec_sub(end_time, start_time);
+ dtime = timespec_to_ns(&diff_time);
+ if (dtime < 33000)
+ ndelay(33000 - dtime);
+ else
+ dev_warn(nvec->dev, "isr time: %llu nsec\n", timespec_to_ns(&diff_time));
+
+ if (!nvec->rx)
+ dev_warn(nvec->dev, "no rx buffer available");
+ else if ((nvec->rx->pos == 1) && (nvec->rx->data[0] == 1)) {
+ valid_proto = 1;
+ } else {
+ dev_warn(nvec->dev, "new transaction "
+ "during send (pos: %d) - trying to retransmit!\n", nvec->tx->pos);
+ nvec->tx->pos = 0;
+ }
+ } else { /* 0x0a, transfer continues */
+ spin_unlock_irqrestore(&nvec->tx_lock, flags);
+ if (nvec->tx != list_first_entry(&nvec->tx_data, struct nvec_msg, node)) {
+ dev_warn(nvec->dev, "tx buffer corrupted");
+ }
+ if ((nvec->tx->pos >= 1) && (nvec->tx->pos < nvec->tx->size)) {
+ valid_proto = 1;
+ }
}
+ }
- if (msg->pos >= msg->size) {
- list_del_init(&msg->node);
- kfree(msg->data);
- kfree(msg);
- schedule_work(&nvec->tx_work);
- nvec->state = NVEC_WAIT;
- }
+ if (!valid_proto) {
+ dev_err(nvec->dev, "invalid protocol (sta:%lx, pos:%d, size: %d)\n", status, nvec->tx->pos, nvec->tx->size);
+ to_send = 0xff;
+ nvec->tx->pos = 0;
+ } else {
+ to_send = nvec->tx->data[nvec->tx->pos++];
}
+
writel(to_send, base + I2C_SL_RCVD);
- gpio_set_value(nvec->gpio, 1);
+ if ((status & RCVD) && valid_proto) {
+ gpio_set_value(nvec->gpio, 1);
+ }
- dev_dbg(nvec->dev, "nvec sent %x\n", to_send);
+ if (nvec->tx->pos == nvec->tx->size) {
+ complete(&nvec->ec_transfer);
+ }
goto handled;
- } else {
- received = readl(base + I2C_SL_RCVD);
+ } else { /* 0x0c, 0x08, 0x1c */
+ if (nvec->rx) {
+ if (status & RCVD) {
+ local_irq_save(flags);
+ received = readl(base + I2C_SL_RCVD);
+ writel(0, base + I2C_SL_RCVD);
+ local_irq_restore(flags);
+ } else
+ received = readl(base + I2C_SL_RCVD);
+
+ if (status & RCVD) { /* new transaction, 0x0c, 0x1c */
+ nvec->rx->pos = 0;
+ nvec->rx->size = 0;
+ nvec->rx->used = 1;
+ if (!(received == nvec->i2c_addr))
+ dev_warn(nvec->dev, "unexpected response from new slave");
+ } else if (nvec->rx->pos == 0) { /* first byte of new transaction */
+ nvec->rx->data[nvec->rx->pos++] = received;
+ nvec->ev_type = (received & 0x80) >> 7; /* Event or Req/Res */
+ nvec->ev_len = (received & 0x60) >> 5; /* Event length */
+ } else { /* transaction continues */
+ if (nvec->rx->pos < MAX_PKT_SIZE)
+ nvec->rx->data[nvec->rx->pos++] = received;
+ if ((nvec->ev_len == NVEC_VAR_SIZE) || (nvec->ev_type == 0)) { /* variable write from master */
+ end_trans = 0;
+ switch (nvec->rx->pos) {
+ case 1:
+ nvec->rx->pos = 0;
+ break;
+ case 2:
+ if ((received == 0) || (received > MAX_PKT_SIZE))
+ nvec->rx->pos = 0;
+ break;
+ default:
+ if (nvec->rx->pos == 2 + nvec->rx->data[1])
+ end_trans = 1;
+ }
+ } else if (nvec->ev_len == NVEC_2BYTES) /* 2 byte event */
+ end_trans = (nvec->rx->pos == 2);
+ else if (nvec->ev_len == NVEC_3BYTES) /* 3 byte event */
+ end_trans = (nvec->rx->pos == 3);
+ else
+ dev_err(nvec->dev, "grap!\n");
+ }
- if (status & RCVD) {
- writel(0, base + I2C_SL_RCVD);
- goto handled;
+ } else {
+ /* FIXME: implement NACK here ! */
+ received = readl(base + I2C_SL_RCVD);
+ dev_err(nvec->dev, "no rx buffer available!\n");
}
- if (nvec->state == NVEC_WAIT) {
- nvec->state = NVEC_READ;
- msg = kzalloc(sizeof(struct nvec_msg), GFP_NOWAIT);
- msg->data = kzalloc(32, GFP_NOWAIT);
- INIT_LIST_HEAD(&msg->node);
- nvec->rx = msg;
- } else
- msg = nvec->rx;
-
- BUG_ON(msg->pos > 32);
-
- msg->data[msg->pos] = received;
- msg->pos++;
- msg->size = msg->pos;
- dev_dbg(nvec->dev, "Got %02lx from Master (pos: %d)!\n",
- received, msg->pos);
+ if (end_trans) {
+ spin_lock_irqsave(&nvec->rx_lock, flags);
+ /* add the received data to the work list
+ and move the ring buffer pointer to the next entry */
+ list_add_tail(&nvec->rx->node, &nvec->rx_data);
+ nvec->rx_pos++;
+ nvec->rx_pos &= RX_BUF_MASK;
+ WARN_ON(nvec->rx_buffer[nvec->rx_pos].used == 1);
+ if (nvec->rx_buffer[nvec->rx_pos].used) {
+ dev_err(nvec->dev, "next buffer full!");
+ }
+ nvec->rx->used = 0;
+ nvec->rx = &nvec->rx_buffer[nvec->rx_pos];
+ spin_unlock_irqrestore(&nvec->rx_lock, flags);
+
+ /* only complete on responses */
+ queue_work(nvec->wq, &nvec->rx_work);
+ }
}
+
handled:
return IRQ_HANDLED;
}
@@ -372,6 +481,7 @@ static int __devinit tegra_nvec_probe(struct platform_device *pdev)
nvec->base = base;
nvec->irq = res->start;
nvec->i2c_clk = i2c_clk;
+ nvec->rx = &nvec->rx_buffer[0];
/* Set the gpio to low when we've got something to say */
err = gpio_request(nvec->gpio, "nvec gpio");
@@ -381,11 +491,17 @@ static int __devinit tegra_nvec_probe(struct platform_device *pdev)
ATOMIC_INIT_NOTIFIER_HEAD(&nvec->notifier_list);
init_completion(&nvec->sync_write);
- sema_init(&nvec->sync_write_mutex, 1);
- INIT_LIST_HEAD(&nvec->tx_data);
+ init_completion(&nvec->ec_transfer);
+ mutex_init(&nvec->sync_write_mutex);
+ mutex_init(&nvec->async_write_mutex);
+ mutex_init(&nvec->dispatch_mutex);
+ spin_lock_init(&nvec->tx_lock);
+ spin_lock_init(&nvec->rx_lock);
INIT_LIST_HEAD(&nvec->rx_data);
+ INIT_LIST_HEAD(&nvec->tx_data);
INIT_WORK(&nvec->rx_work, nvec_dispatch);
INIT_WORK(&nvec->tx_work, nvec_request_master);
+ nvec->wq = alloc_workqueue("nvec", WQ_NON_REENTRANT, 1);
err = request_irq(nvec->irq, nvec_interrupt, 0, "nvec", nvec);
if (err) {
@@ -413,13 +529,14 @@ static int __devinit tegra_nvec_probe(struct platform_device *pdev)
/* Get Firmware Version */
msg = nvec_write_sync(nvec, EC_GET_FIRMWARE_VERSION,
- sizeof(EC_GET_FIRMWARE_VERSION));
+ sizeof(EC_GET_FIRMWARE_VERSION));
- dev_warn(nvec->dev, "ec firmware version %02x.%02x.%02x / %02x\n",
- msg->data[4], msg->data[5], msg->data[6], msg->data[7]);
+ if (msg) {
+ dev_warn(nvec->dev, "ec firmware version %02x.%02x.%02x / %02x\n",
+ msg->data[4], msg->data[5], msg->data[6], msg->data[7]);
- kfree(msg->data);
- kfree(msg);
+ msg->used = 0;
+ }
ret = mfd_add_devices(nvec->dev, -1, nvec_devices,
ARRAY_SIZE(nvec_devices), base, 0);
@@ -453,6 +570,7 @@ static int __devexit tegra_nvec_remove(struct platform_device *pdev)
free_irq(nvec->irq, &nvec_interrupt);
iounmap(nvec->base);
gpio_free(nvec->gpio);
+ destroy_workqueue(nvec->wq);
kfree(nvec);
return 0;
diff --git a/drivers/staging/nvec/nvec.h b/drivers/staging/nvec/nvec.h
index bdeb9da..ceedcbb 100644
--- a/drivers/staging/nvec/nvec.h
+++ b/drivers/staging/nvec/nvec.h
@@ -18,39 +18,33 @@
#include <linux/semaphore.h>
-typedef enum {
+#define RX_BUF_ORDER 4
+#define RX_BUF_SIZE (1 << RX_BUF_ORDER)
+#define RX_BUF_MASK (RX_BUF_SIZE - 1)
+#define MAX_PKT_SIZE 200
+
+enum {
NVEC_2BYTES,
NVEC_3BYTES,
- NVEC_VAR_SIZE
-} nvec_size;
-
-typedef enum {
- NOT_REALLY,
- YES,
- NOT_AT_ALL,
-} how_care;
+ NVEC_VAR_SIZE,
+};
-typedef enum {
+enum {
NVEC_SYS = 1,
NVEC_BAT,
NVEC_KBD = 5,
NVEC_PS2,
NVEC_CNTL,
NVEC_KB_EVT = 0x80,
- NVEC_PS2_EVT
-} nvec_event;
-
-typedef enum {
- NVEC_WAIT,
- NVEC_READ,
- NVEC_WRITE
-} nvec_state;
+ NVEC_PS2_EVT,
+};
struct nvec_msg {
- unsigned char *data;
+ struct list_head node;
+ unsigned char data[MAX_PKT_SIZE];
unsigned short size;
unsigned short pos;
- struct list_head node;
+ unsigned short used;
};
struct nvec_subdev {
@@ -71,15 +65,27 @@ struct nvec_chip {
int i2c_addr;
void __iomem *base;
struct clk *i2c_clk;
- nvec_state state;
struct atomic_notifier_head notifier_list;
struct list_head rx_data, tx_data;
struct notifier_block nvec_status_notifier;
struct work_struct rx_work, tx_work;
- struct nvec_msg *rx, *tx;
+ struct workqueue_struct *wq;
+ struct nvec_msg *rx;
+ struct nvec_msg rx_buffer[RX_BUF_SIZE];
+ /* points to the position in rx buffer */
+ int rx_pos;
+ int ev_len, ev_type;
+
+ struct nvec_msg *tx;
+ struct nvec_msg tx_scratch;
+ struct completion ec_transfer;
+
+ struct mutex async_write_mutex;
+ struct mutex dispatch_mutex;
+ spinlock_t tx_lock, rx_lock;
/* sync write stuff */
- struct semaphore sync_write_mutex;
+ struct mutex sync_write_mutex;
struct completion sync_write;
u16 sync_write_pending;
struct nvec_msg *last_sync_msg;
@@ -96,10 +102,6 @@ extern int nvec_unregister_notifier(struct device *dev,
struct notifier_block *nb,
unsigned int events);
-const char *nvec_send_msg(unsigned char *src, unsigned char *dst_size,
- how_care care_resp,
- void (*rt_handler) (unsigned char *data));
-
#define I2C_CNFG 0x00
#define I2C_CNFG_PACKET_MODE_EN (1<<10)
#define I2C_CNFG_NEW_MASTER_SFM (1<<11)
diff --git a/drivers/staging/nvec/nvec_kbd.c b/drivers/staging/nvec/nvec_kbd.c
index 36f8060..aae4494 100644
--- a/drivers/staging/nvec/nvec_kbd.c
+++ b/drivers/staging/nvec/nvec_kbd.c
@@ -40,7 +40,7 @@ static int nvec_keys_notifier(struct notifier_block *nb,
unsigned char *msg = (unsigned char *)data;
if (event_type == NVEC_KB_EVT) {
- nvec_size _size = (msg[0] & (3 << 5)) >> 5;
+ int _size = (msg[0] & (3 << 5)) >> 5;
/* power on/off button */
if (_size == NVEC_VAR_SIZE)
--
1.7.4.1
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