Re: [PATCH 1/4] staging: r8188eu: add error handling of rtw_read8

[Pavel Skripkin <paskripkin@xxxxxxxxx>]

Hi Dan,

On 5/19/22 07:33, Dan Carpenter wrote:
> On Thu, May 19, 2022 at 01:11:51AM +0300, Pavel Skripkin wrote:
> > @@ -240,12 +259,14 @@ int rtl8188e_firmware_download(struct adapter *padapter)
> >  {
> >  	int ret = _SUCCESS;
> >  	u8 write_fw_retry = 0;
> > +	u8 reg;
> >  	unsigned long fwdl_timeout;
> >  	struct dvobj_priv *dvobj = adapter_to_dvobj(padapter);
> >  	struct device *device = dvobj_to_dev(dvobj);
> >  	struct rt_firmware_hdr *fwhdr = NULL;
> >  	u8 *fw_data;
> >  	u32 fw_size;
> > +	int res;
> >  
> >  	if (!dvobj->firmware.data)
> >  		ret = load_firmware(&dvobj->firmware, device);
> > @@ -269,7 +290,11 @@ int rtl8188e_firmware_download(struct adapter *padapter)
> >  
> >  	/*  Suggested by Filen. If 8051 is running in RAM code, driver should inform Fw to reset by itself, */
> >  	/*  or it will cause download Fw fail. 2010.02.01. by tynli. */
> > -	if (rtw_read8(padapter, REG_MCUFWDL) & RAM_DL_SEL) { /* 8051 RAM code */
> > +	res = rtw_read8(padapter, REG_MCUFWDL, &reg);
> > +	if (res)
> > +		goto exit;
>
> You didn't introduce this bug, but this path needs to have an error code
> set.  Also we really need to get rid of the _FAIL garbage.  When I saw
> this, I got "ret" and "res" mixed up so I thought we were returning
> negative error codes instead of _FAIL.  That would   But then I saw we
> are returning success.

I see now, that 'res' and 'ret' got mixed up in my mind too. Will fix up


> > +
> > +	if (reg & RAM_DL_SEL) { /* 8051 RAM code */
> >  		rtw_write8(padapter, REG_MCUFWDL, 0x00);
> >  		rtw_reset_8051(padapter);
> >  	}
> > @@ -278,7 +303,14 @@ int rtl8188e_firmware_download(struct adapter *padapter)
> >  	fwdl_timeout = jiffies + msecs_to_jiffies(500);
> >  	while (1) {
> >  		/* reset the FWDL chksum */
> > -		rtw_write8(padapter, REG_MCUFWDL, rtw_read8(padapter, REG_MCUFWDL) | FWDL_CHKSUM_RPT);
> > +		res = rtw_read8(padapter, REG_MCUFWDL, &reg);
> > +		if (res == -ENODEV)
> > +			break;
> > +
> > +		if (res)
> > +			continue;
>
> This continue is wrong.  If res = -EPERM then it's a forever loop.
> Let's just break for every error.

I was trying to avoid strict breaking the loop on any error, since I am 
afraid this might break the driver.

What about:

	do {
		/* reset the FWDL chksum */
		ret = rtw_read8(padapter, REG_MCUFWDL, &reg);
		if (ret == -ENODEV || ret == -EPERM)
			break;

		if (ret) {
			ret == _FAIL;
			continue;
		}

		rtw_write8(padapter, REG_MCUFWDL, reg | FWDL_CHKSUM_RPT);

		ret = write_fw(padapter, fw_data, fw_size);
	} while (!(ret == _SUCCESS ||
		    (time_after(jiffies, fwdl_timeout) && write_fw_retry++ >= 3)))

The idea is to break only on fatal errors to make things less strict




With regards,
Pavel Skripkin

Attachment: OpenPGP_signature
Description: OpenPGP digital signature