Re: [PATCH v7 11/13] slimbus: qcom: Add Qualcomm Slimbus controller driver

[Srinivas Kandagatla]

Thanks for your review,

On 23/11/17 16:42, Jonathan NeuschÃfer wrote:
> Hello Srinivas and Charles,
>
> On Thu, Nov 23, 2017 at 10:07:03AM +0000, Charles Keepax wrote:
> > On Wed, Nov 15, 2017 at 02:10:41PM +0000, srinivas.kandagatla@xxxxxxxxxx wrote:
> > > From: Sagar Dharia <sdharia@xxxxxxxxxxxxxx>
> > >
> > > This controller driver programs manager, interface, and framer
> > > devices for Qualcomm's slimbus HW block.
> > > Manager component currently implements logical address setting,
> > > and messaging interface.
> > > Interface device reports bus synchronization information, and framer
> > > device clocks the bus from the time it's woken up, until clock-pause
> > > is executed by the manager device.
> > >
> > > Signed-off-by: Sagar Dharia <sdharia@xxxxxxxxxxxxxx>
> > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > > ---
> [...]
> > > +static void qcom_slim_rxwq(struct work_struct *work)
> > > +{
> > > +	u8 buf[SLIM_MSGQ_BUF_LEN];
> > > +	u8 mc, mt, len;
> > > +	int i, ret;
> > > +	struct qcom_slim_ctrl *ctrl = container_of(work, struct qcom_slim_ctrl,
> > > +						 wd);
> > > +
> > > +	while ((slim_get_current_rxbuf(ctrl, buf)) != -ENODATA) {
> > > +		len = SLIM_HEADER_GET_RL(buf[0]);
> > > +		mt = SLIM_HEADER_GET_MT(buf[0]);
> > > +		mc = SLIM_HEADER_GET_MC(buf[1]);
> > > +		if (mt == SLIM_MSG_MT_CORE &&
> > > +			mc == SLIM_MSG_MC_REPORT_PRESENT) {
> > > +			u8 laddr;
> > > +			struct slim_eaddr ea;
> > > +			u8 e_addr[6];
> > > +
> > > +			for (i = 0; i < 6; i++)
> > > +				e_addr[i] = buf[7-i];
> > > +
> > > +			ea.manf_id = (u16)(e_addr[5] << 8) | e_addr[4];
> > > +			ea.prod_code = (u16)(e_addr[3] << 8) | e_addr[2];
> > > +			ea.dev_index = e_addr[1];
> > > +			ea.instance = e_addr[0];
> >
> > If we are just bitshifting this out of the bytes does it really
> > make it much more clear to reverse the byte order first? Feels
> > like you might as well shift it out of buf directly.
>
> In any case, there is a predefined function to make this code a little
> nicer in <asm/byteorder.h>:
>
> 	le16_to_cpu(x):  Converts the 16-bit little endian value x to
> 	                 CPU-endian
> 	le16_to_cpup(p): Converts the 16-bit little endian value pointed
> 	                 to by p to CPU-endian
>
> If you use le16_to_cpup, you need to cast your pointer to __le16 *:
>
> 	ea.manf_id = le16_to_cpup((__le16 *)&e_addr[4]);
It Looks like I can make use of these apis here, I will give this a go 
to cleanup this part of the code.

thanks,
srini