Message-ID: <19F8576C6E063C45BE387C64729E739404AA21CEA1@dbde02.ent.ti.com>
Date:	Thu, 7 Oct 2010 01:38:16 +0530
From:	"Savoy, Pavan" <pavan_savoy@...com>
To:	Jiri Slaby <jirislaby@...il.com>
CC:	"gregkh@...e.de" <gregkh@...e.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
	"alan@...rguk.ukuu.org.uk" <alan@...rguk.ukuu.org.uk>
Subject: RE: [PATCH 1/2] drivers:staging:ti-st: move TI_ST from staging

Jiri,
 

> -----Original Message-----
> From: Jiri Slaby [mailto:jirislaby@...il.com]
> Sent: Wednesday, October 06, 2010 2:47 PM
> To: Savoy, Pavan
> Cc: gregkh@...e.de; linux-kernel@...r.kernel.org; devel@...verdev.osuosl.org;
> alan@...rguk.ukuu.org.uk
> Subject: Re: [PATCH 1/2] drivers:staging:ti-st: move TI_ST from staging
> 
> Hi,
> 
> I have few comments below.

Thanks for the comments, will send patches for these,
For others, please check below...

> On 10/06/2010 06:18 PM, pavan_savoy@...com wrote:
> > --- /dev/null
> > +++ b/drivers/misc/ti-st/st_core.c
> > @@ -0,0 +1,1031 @@
> ...
> > +#define PROTO_ENTRY(type, name)	name
> > +const unsigned char *protocol_strngs[] = {
> > +	PROTO_ENTRY(ST_BT, "Bluetooth"),
> > +	PROTO_ENTRY(ST_FM, "FM"),
> > +	PROTO_ENTRY(ST_GPS, "GPS"),
> > +};
> 
> Is this planned to be used somewhere?

Yes- would go in the debugfs.
Doesn't it already? Will check up, & will remove if not required.

> > +void st_send_frame(enum proto_type protoid, struct st_data_s *st_gdata)
> > +{
> > +	pr_info(" %s(prot:%d) ", __func__, protoid);
> 
> This is rather a kind of debug info... (with missing \n)
> 
> > +	if (unlikely
> > +	    (st_gdata == NULL || st_gdata->rx_skb == NULL
> > +	     || st_gdata->list[protoid] == NULL)) {
> 
> This is not much readable.
> 
> > +		pr_err("protocol %d not registered, no data to send?",
> > +			   protoid);
> 
> Missing \n. And all over the code.

With pr_fmt defined in each source file, the "\n" is not necessary.
I don't see the logs getting all jumbled up in one line.

However If I don't have a pr_fmt, I see the need for "\n" - Please suggest.

> > +static inline int st_check_data_len(struct st_data_s *st_gdata,
> 
> It doesn't look like a candidate for inlining.

Because?

> > +	int protoid, int len)
> > +{
> > +	register int room = skb_tailroom(st_gdata->rx_skb);
> 
> register... hmm, leave this on compiler.

Yes, I should have done this, Will post a patch for it.

> > +	pr_debug("len %d room %d", len, room);
> > +
> > +	if (!len) {
> > +		/* Received packet has only packet header and
> > +		 * has zero length payload. So, ask ST CORE to
> > +		 * forward the packet to protocol driver (BT/FM/GPS)
> > +		 */
> > +		st_send_frame(protoid, st_gdata);
> > +
> > +	} else if (len > room) {
> > +		/* Received packet's payload length is larger.
> > +		 * We can't accommodate it in created skb.
> > +		 */
> > +		pr_err("Data length is too large len %d room %d", len,
> > +			   room);
> > +		kfree_skb(st_gdata->rx_skb);
> > +	} else {
> > +		/* Packet header has non-zero payload length and
> > +		 * we have enough space in created skb. Lets read
> > +		 * payload data */
> > +		st_gdata->rx_state = ST_BT_W4_DATA;
> > +		st_gdata->rx_count = len;
> > +		return len;
> > +	}
> > +
> > +	/* Change ST state to continue to process next
> > +	 * packet */
> > +	st_gdata->rx_state = ST_W4_PACKET_TYPE;
> > +	st_gdata->rx_skb = NULL;
> > +	st_gdata->rx_count = 0;
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * st_wakeup_ack - internal function for action when wake-up ack
> > + *	received
> > + */
> > +static inline void st_wakeup_ack(struct st_data_s *st_gdata,
> > +	unsigned char cmd)
> > +{
> > +	register struct sk_buff *waiting_skb;
> > +	unsigned long flags = 0;
> 
> No need to initialize.

Correct.

> > +	spin_lock_irqsave(&st_gdata->lock, flags);
> > +	/* de-Q from waitQ and Q in txQ now that the
> > +	 * chip is awake
> > +	 */
> > +	while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
> > +		skb_queue_tail(&st_gdata->txq, waiting_skb);
> > +
> > +	/* state forwarded to ST LL */
> > +	st_ll_sleep_state(st_gdata, (unsigned long)cmd);
> > +	spin_unlock_irqrestore(&st_gdata->lock, flags);
> > +
> > +	/* wake up to send the recently copied skbs from waitQ */
> > +	st_tx_wakeup(st_gdata);
> > +}
> > +
> > +/**
> > + * st_int_recv - ST's internal receive function.
> > + *	Decodes received RAW data and forwards to corresponding
> > + *	client drivers (Bluetooth,FM,GPS..etc).
> > + *	This can receive various types of packets,
> > + *	HCI-Events, ACL, SCO, 4 types of HCI-LL PM packets
> > + *	CH-8 packets from FM, CH-9 packets from GPS cores.
> > + */
> > +void st_int_recv(void *disc_data,
> > +	const unsigned char *data, long count)
> > +{
> > +	register char *ptr;
> > +	struct hci_event_hdr *eh;
> > +	struct hci_acl_hdr *ah;
> > +	struct hci_sco_hdr *sh;
> > +	struct fm_event_hdr *fm;
> > +	struct gps_event_hdr *gps;
> > +	register int len = 0, type = 0, dlen = 0;
> > +	static enum proto_type protoid = ST_MAX;
> > +	struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
> > +
> > +	ptr = (char *)data;
> 
> Too much of casts and registers.

Registers will all go away.

> > +	/* tty_receive sent null ? */
> > +	if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
> > +		pr_err(" received null from TTY ");
> > +		return;
> > +	}
> > +
> > +	pr_info("count %ld rx_state %ld"
> > +		   "rx_count %ld", count, st_gdata->rx_state,
> > +		   st_gdata->rx_count);
> 
> It's a debug info. + \n
> 
> > +int st_core_init(struct st_data_s **core_data)
> > +{
> > +	struct st_data_s *st_gdata;
> > +	long err;
> > +	static struct tty_ldisc_ops *st_ldisc_ops;
> > +
> > +	/* populate and register to TTY line discipline */
> > +	st_ldisc_ops = kzalloc(sizeof(*st_ldisc_ops), GFP_KERNEL);
> > +	if (!st_ldisc_ops) {
> > +		pr_err("no mem to allocate");
> > +		return -ENOMEM;
> > +	}
> > +
> > +	st_ldisc_ops->magic = TTY_LDISC_MAGIC;
> > +	st_ldisc_ops->name = "n_st";	/*"n_hci"; */
> > +	st_ldisc_ops->open = st_tty_open;
> > +	st_ldisc_ops->close = st_tty_close;
> > +	st_ldisc_ops->receive_buf = st_tty_receive;
> > +	st_ldisc_ops->write_wakeup = st_tty_wakeup;
> > +	st_ldisc_ops->flush_buffer = st_tty_flush_buffer;
> > +	st_ldisc_ops->owner = THIS_MODULE;
> 
> This can be static structure, you don't need to allocate this on heap.
> It should be a singleton.

Yes, I got this comment before, but is it just a style issue?
I want to keep this in heap because some day, I hope TTY ldics have their own
private_data, which I can pass around like the tty_struct's data.
and having them in heap, I plan to keep a reference to ops structure, so that I
can pass around and use ops->private_data everywhere ..

> > +
> > +	err = tty_register_ldisc(N_TI_WL, st_ldisc_ops);
> > +	if (err) {
> > +		pr_err("error registering %d line discipline %ld",
> > +			   N_TI_WL, err);
> > +		kfree(st_ldisc_ops);
> > +		return err;
> > +	}
> > +	pr_debug("registered n_shared line discipline");
> > +
> > +	st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
> > +	if (!st_gdata) {
> > +		pr_err("memory allocation failed");
> > +		err = tty_unregister_ldisc(N_TI_WL);
> > +		if (err)
> > +			pr_err("unable to un-register ldisc %ld", err);
> > +		kfree(st_ldisc_ops);
> > +		err = -ENOMEM;
> > +		return err;
> > +	}
> > +
> > +	/* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module
> skb's
> > +	 * will be pushed in this queue for actual transmission.
> > +	 */
> > +	skb_queue_head_init(&st_gdata->txq);
> > +	skb_queue_head_init(&st_gdata->tx_waitq);
> > +
> > +	/* Locking used in st_int_enqueue() to avoid multiple execution */
> > +	spin_lock_init(&st_gdata->lock);
> > +
> > +	/* ldisc_ops ref to be only used in __exit of module */
> > +	st_gdata->ldisc_ops = st_ldisc_ops;
> > +
> > +#if 0
> > +	err = st_kim_init();
> > +	if (err) {
> > +		pr_err("error during kim initialization(%ld)", err);
> > +		kfree(st_gdata);
> > +		err = tty_unregister_ldisc(N_TI_WL);
> > +		if (err)
> > +			pr_err("unable to un-register ldisc");
> > +		kfree(st_ldisc_ops);
> > +		return -1;
> > +	}
> > +#endif
> > +
> > +	err = st_ll_init(st_gdata);
> > +	if (err) {
> > +		pr_err("error during st_ll initialization(%ld)", err);
> > +		kfree(st_gdata);
> > +		err = tty_unregister_ldisc(N_TI_WL);
> > +		if (err)
> > +			pr_err("unable to un-register ldisc");
> > +		kfree(st_ldisc_ops);
> 
> Please use goto fail-paths.

Hnm
OK, but there is not much cleanup before failed return in there.
Will go ahead and fix it anyway

> > +		return -1;
> > +	}
> > +	*core_data = st_gdata;
> > +	return 0;
> > +}
> ...
> > --- /dev/null
> > +++ b/drivers/misc/ti-st/st_kim.c
> > @@ -0,0 +1,798 @@
> ...
> > +#define PROTO_ENTRY(type, name)	name
> > +const unsigned char *protocol_names[] = {
> > +	PROTO_ENTRY(ST_BT, "Bluetooth"),
> > +	PROTO_ENTRY(ST_FM, "FM"),
> > +	PROTO_ENTRY(ST_GPS, "GPS"),
> > +};
> 
> Here they appear again. It should be static and have a better name to
> not collide with the rest of the world.

They are used for the entries I expose in the debugfs.

> > +#define MAX_ST_DEVICES	3	/* Imagine 1 on each UART for now */
> > +struct platform_device *st_kim_devices[MAX_ST_DEVICES];
> 
> static? Doesn't sparse warn about this?
> 
> > +void kim_int_recv(struct kim_data_s *kim_gdata,
> > +	const unsigned char *data, long count)
> > +{
> > +	register char *ptr;
> > +	struct hci_event_hdr *eh;
> > +	register int len = 0, type = 0;
> 
> registers
> 
> > +	pr_debug("%s", __func__);
> 
> \n
> 
> > +	/* Decode received bytes here */
> > +	ptr = (char *)data;
> 
> Casting from const to non-const. It doesn't look correct.

So, would I rather declare ptr as const?

> > +static long read_local_version(struct kim_data_s *kim_gdata, char
> *bts_scr_name)
> > +{
> > +	unsigned short version = 0, chip = 0, min_ver = 0, maj_ver = 0;
> 
> No need to initialize all of them.
> 
> > +	char read_ver_cmd[] = { 0x01, 0x01, 0x10, 0x00 };
> 
> static const perhaps.

Yes, Correct, patch on the way.
 
> > +long st_kim_start(void *kim_data)
> > +{
> > +	long err = 0;
> > +	long retry = POR_RETRY_COUNT;
> > +	struct kim_data_s	*kim_gdata = (struct kim_data_s *)kim_data;
> > +
> > +	pr_info(" %s", __func__);
> > +
> > +	do {
> > +		/* TODO: this is only because rfkill sub-system
> > +		 * doesn't send events to user-space if the state
> > +		 * isn't changed
> > +		 */
> > +		rfkill_set_hw_state(kim_gdata->rfkill[ST_BT], 1);
> > +		/* Configure BT nShutdown to HIGH state */
> > +		gpio_set_value(kim_gdata->gpios[ST_BT], GPIO_LOW);
> > +		mdelay(5);	/* FIXME: a proper toggle */
> > +		gpio_set_value(kim_gdata->gpios[ST_BT], GPIO_HIGH);
> > +		mdelay(100);
> 
> You can sleep here instead (below you wait for completion). 100 ms of
> busy waiting is way too much.

It's agreed upon from the process, since it is in a process context.
Like's a device's open or hci0's UP.

> > +		/* re-initialize the completion */
> > +		INIT_COMPLETION(kim_gdata->ldisc_installed);
> > +#if 0 /* older way of signalling user-space UIM */
> > +		/* send signal to UIM */
> > +		err = kill_pid(find_get_pid(kim_gdata->uim_pid), SIGUSR2, 0);
> > +		if (err != 0) {
> > +			pr_info(" sending SIGUSR2 to uim failed %ld", err);
> > +			err = -1;
> > +			continue;
> > +		}
> > +#endif
> > +		/* unblock and send event to UIM via /dev/rfkill */
> > +		rfkill_set_hw_state(kim_gdata->rfkill[ST_BT], 0);
> > +		/* wait for ldisc to be installed */
> > +		err = wait_for_completion_timeout(&kim_gdata->ldisc_installed,
> > +				msecs_to_jiffies(LDISC_TIME));
> 
> regards,

Thanks for comments, Will post a patch for several,
Please provide your feedback on others.

Regards,
Pavan


> js
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