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Improve CEC driver by :
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- Detecting properly HPD HDMI signal (connection and disconnection)
- Avoiding bad poll return which can lead to read infinite blocking with
  libcec!
- Removing useless events
- Adding timeout guard in case no ACK nor NACK is returned by controller after a
  write
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@wolfgar
wolfgar committed Apr 23, 2014
1 parent 86d55a0 commit 342b93f
Showing 1 changed file with 54 additions and 51 deletions.
105 changes: 54 additions & 51 deletions drivers/mxc/hdmi-cec/mxc_hdmi-cec.c
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Expand Up @@ -62,7 +62,8 @@ struct hdmi_cec_priv {
bool cec_state;
u8 last_msg[MAX_MESSAGE_LEN];
u8 msg_len;
u8 latest_cec_stat;
u16 latest_cec_stat;
u8 link_status;
u32 cec_irq;
spinlock_t irq_lock;
struct delayed_work hdmi_cec_work;
Expand Down Expand Up @@ -91,18 +92,28 @@ static int tx_answer;
static irqreturn_t mxc_hdmi_cec_isr(int irq, void *data)
{
struct hdmi_cec_priv *hdmi_cec = data;
u8 cec_stat = 0;
u16 cec_stat = 0;
unsigned long flags;
u8 phy_stat0;

spin_lock_irqsave(&hdmi_cec->irq_lock, flags);

hdmi_writeb(0x7f, HDMI_IH_MUTE_CEC_STAT0);

cec_stat = hdmi_readb(HDMI_IH_CEC_STAT0);
hdmi_writeb(cec_stat, HDMI_IH_CEC_STAT0);
phy_stat0 = hdmi_readb(HDMI_PHY_STAT0) & 0x02;
if (hdmi_cec->link_status ^ phy_stat0) {
/* HPD value changed */
hdmi_cec->link_status = phy_stat0;
if (hdmi_cec->link_status)
cec_stat |= 0x80; /* Connected */
else
cec_stat |= 0x100; /* Disconnected */
}
if ((cec_stat & (HDMI_IH_CEC_STAT0_ERROR_INIT | \
HDMI_IH_CEC_STAT0_NACK | HDMI_IH_CEC_STAT0_EOM | \
HDMI_IH_CEC_STAT0_DONE)) == 0) {
HDMI_IH_CEC_STAT0_DONE | 0x180)) == 0) {
spin_unlock_irqrestore(&hdmi_cec->irq_lock, flags);
return IRQ_HANDLED;
}
Expand All @@ -126,21 +137,11 @@ void mxc_hdmi_cec_handle(u16 cec_stat)
return;

if (cec_stat & HDMI_IH_CEC_STAT0_DONE) {
event = vmalloc(sizeof(struct hdmi_cec_event));
if (NULL == event) {
pr_err("%s:Don't get memory!\n", __func__);
return;
}
memset(event, 0, sizeof(struct hdmi_cec_event));
event->event_type = MESSAGE_TYPE_SEND_SUCCESS;
mutex_lock(&hdmi_cec_data.lock);
list_add_tail(&event->list, &head);
mutex_unlock(&hdmi_cec_data.lock);
tx_answer = cec_stat;
wake_up(&tx_cec_queue);
}
/*EOM is detected so that the received data is ready in the receiver data buffer*/
else if (cec_stat & HDMI_IH_CEC_STAT0_EOM) {
if (cec_stat & HDMI_IH_CEC_STAT0_EOM) {
hdmi_writeb(0x02, HDMI_IH_CEC_STAT0);
event = vmalloc(sizeof(struct hdmi_cec_event));
if (NULL == event) {
Expand All @@ -163,13 +164,15 @@ void mxc_hdmi_cec_handle(u16 cec_stat)
wake_up(&hdmi_cec_queue);
}
/*An error is detected on cec line (for initiator only). */
else if (cec_stat & HDMI_IH_CEC_STAT0_ERROR_INIT) {
if (cec_stat & HDMI_IH_CEC_STAT0_ERROR_INIT) {
mutex_lock(&hdmi_cec_data.lock);
hdmi_cec_data.send_error++;
if (hdmi_cec_data.send_error > 5) {
pr_err("%s:Re-transmission is attempted more than 5 times!\n", __func__);
if (hdmi_cec_data.send_error > 2) {
pr_err("%s:Re-transmission is attempted more than 2 times!\n", __func__);
hdmi_cec_data.send_error = 0;
mutex_unlock(&hdmi_cec_data.lock);
tx_answer = cec_stat;
wake_up(&tx_cec_queue);
return;
}
for (i = 0; i < hdmi_cec_data.msg_len; i++)
Expand All @@ -182,25 +185,17 @@ void mxc_hdmi_cec_handle(u16 cec_stat)
}
/*A frame is not acknowledged in a directly addressed message. Or a frame is negatively acknowledged in
a broadcast message (for initiator only).*/
else if (cec_stat & HDMI_IH_CEC_STAT0_NACK) {
event = vmalloc(sizeof(struct hdmi_cec_event));
if (NULL == event) {
pr_err("%s:Don't get memory!\n", __func__);
return;
}
memset(event, 0, sizeof(struct hdmi_cec_event));
event->event_type = MESSAGE_TYPE_NOACK;
mutex_lock(&hdmi_cec_data.lock);
list_add_tail(&event->list, &head);
mutex_unlock(&hdmi_cec_data.lock);
if (cec_stat & HDMI_IH_CEC_STAT0_NACK) {
tx_answer = cec_stat;
wake_up(&tx_cec_queue);
}
/*An error is notified by a follower. Abnormal logic data bit error (for follower).*/
else if (cec_stat & HDMI_IH_CEC_STAT0_ERROR_FOLL)
if (cec_stat & HDMI_IH_CEC_STAT0_ERROR_FOLL) {
hdmi_cec_data.receive_error++;
}
/*HDMI cable connected*/
else if (cec_stat & 0x80) {
if (cec_stat & 0x80) {
pr_info("HDMI link connected\n");
event = vmalloc(sizeof(struct hdmi_cec_event));
if (NULL == event) {
pr_err("%s:Don't get memory!\n", __func__);
Expand All @@ -214,7 +209,8 @@ void mxc_hdmi_cec_handle(u16 cec_stat)
wake_up(&hdmi_cec_queue);
}
/*HDMI cable disconnected*/
else if (cec_stat & 0x100) {
if (cec_stat & 0x100) {
pr_info("HDMI link disconnected\n");
event = vmalloc(sizeof(struct hdmi_cec_event));
if (NULL == event) {
pr_err("%s:Don't get memory!\n", __func__);
Expand Down Expand Up @@ -304,6 +300,7 @@ static ssize_t hdmi_cec_write(struct file *file, const char __user *buf,
u8 msg_len = 0, val = 0;

pr_debug("function : %s\n", __func__);

if (!open_count)
return -ENODEV;
mutex_lock(&hdmi_cec_data.lock);
Expand Down Expand Up @@ -332,19 +329,36 @@ static ssize_t hdmi_cec_write(struct file *file, const char __user *buf,
hdmi_cec_data.msg_len = msg_len;
mutex_unlock(&hdmi_cec_data.lock);

if (wait_event_interruptible(tx_cec_queue, tx_answer != 0)) {
if (wait_event_interruptible_timeout(tx_cec_queue, tx_answer != 0, HZ) < 0) {
return -ERESTARTSYS;
}
if (tx_answer & HDMI_IH_CEC_STAT0_DONE)
/* msg correctly sent */
ret = msg_len;
else
ret = -EIO;

return ret;
}


static void hdmi_stop_device(void)
{
u8 val;

hdmi_writeb(0x10, HDMI_CEC_CTRL);
val = HDMI_IH_CEC_STAT0_WAKEUP | HDMI_IH_CEC_STAT0_ERROR_FOLL | HDMI_IH_CEC_STAT0_ERROR_INIT | HDMI_IH_CEC_STAT0_ARB_LOST | \
HDMI_IH_CEC_STAT0_NACK | HDMI_IH_CEC_STAT0_EOM | HDMI_IH_CEC_STAT0_DONE;
hdmi_writeb(val, HDMI_CEC_MASK);
hdmi_writeb(val, HDMI_IH_MUTE_CEC_STAT0);
hdmi_writeb(0x0, HDMI_CEC_POLARITY);
val = hdmi_readb(HDMI_MC_CLKDIS);
val |= HDMI_MC_CLKDIS_CECCLK_DISABLE;
hdmi_writeb(val, HDMI_MC_CLKDIS);
mutex_lock(&hdmi_cec_data.lock);
hdmi_cec_data.cec_state = false;
mutex_unlock(&hdmi_cec_data.lock);
}

/*!
* @brief IO ctrl function for vpu file operation
* @param cmd IO ctrl command
Expand Down Expand Up @@ -399,23 +413,13 @@ static long hdmi_cec_ioctl(struct file *filp, u_int cmd,
val = HDMI_IH_CEC_STAT0_WAKEUP | HDMI_IH_CEC_STAT0_ERROR_FOLL | HDMI_IH_CEC_STAT0_ARB_LOST;
hdmi_writeb(val, HDMI_CEC_MASK);
hdmi_writeb(val, HDMI_IH_MUTE_CEC_STAT0);
hdmi_cec_data.link_status = hdmi_readb(HDMI_PHY_STAT0) & 0x02;
mutex_lock(&hdmi_cec_data.lock);
hdmi_cec_data.cec_state = true;
mutex_unlock(&hdmi_cec_data.lock);
break;
case HDMICEC_IOC_STOPDEVICE:
hdmi_writeb(0x10, HDMI_CEC_CTRL);
val = HDMI_IH_CEC_STAT0_WAKEUP | HDMI_IH_CEC_STAT0_ERROR_FOLL | HDMI_IH_CEC_STAT0_ERROR_INIT | HDMI_IH_CEC_STAT0_ARB_LOST | \
HDMI_IH_CEC_STAT0_NACK | HDMI_IH_CEC_STAT0_EOM | HDMI_IH_CEC_STAT0_DONE;
hdmi_writeb(val, HDMI_CEC_MASK);
hdmi_writeb(val, HDMI_IH_MUTE_CEC_STAT0);
hdmi_writeb(0x0, HDMI_CEC_POLARITY);
val = hdmi_readb(HDMI_MC_CLKDIS);
val |= HDMI_MC_CLKDIS_CECCLK_DISABLE;
hdmi_writeb(val, HDMI_MC_CLKDIS);
mutex_lock(&hdmi_cec_data.lock);
hdmi_cec_data.cec_state = false;
mutex_unlock(&hdmi_cec_data.lock);
hdmi_stop_device();
break;
case HDMICEC_IOC_GETPHYADDRESS:
hdmi_get_edid_cfg(&hdmi_edid_cfg);
Expand Down Expand Up @@ -455,18 +459,14 @@ static unsigned int hdmi_cec_poll(struct file *file, poll_table *wait)

pr_debug("function : %s\n", __func__);

if (!open_count)
return -ENODEV;
if (false == hdmi_cec_data.cec_state)
return -EACCES;

poll_wait(file, &hdmi_cec_queue, wait);

/* Always writable */
mask = (POLLOUT | POLLWRNORM);
mutex_lock(&hdmi_cec_data.lock);
if (!list_empty(&head))
mask |= (POLLIN | POLLRDNORM);

mutex_unlock(&hdmi_cec_data.lock);
return mask;
}

Expand Down Expand Up @@ -583,6 +583,9 @@ static int __init hdmi_cec_init(void)
static void __exit hdmi_cec_exit(void)
{

if (hdmi_cec_data.cec_state)
hdmi_stop_device();

if (hdmi_cec_data.cec_irq > 0)
free_irq(hdmi_cec_data.cec_irq, &hdmi_cec_data);

Expand Down

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