Re: [PATCH 2/4] rt2x00: move disabling of DMA before loading firmware

[Stanislaw Gruszka <sgruszka@redhat.com>]

Hello,

On Tue, Mar 27, 2012 at 08:11:07PM +0200, Gertjan van Wingerde wrote:
> >  	/*
> > -	 * Disable DMA, will be reenabled later when enabling
> > -	 * the radio.
> > -	 */
> > -	rt2800_register_read(rt2x00dev, WPDMA_GLO_CFG, &reg);
> > -	rt2x00_set_field32(&reg, WPDMA_GLO_CFG_ENABLE_TX_DMA, 0);
> > -	rt2x00_set_field32(&reg, WPDMA_GLO_CFG_ENABLE_RX_DMA, 0);
> > -	rt2800_register_write(rt2x00dev, WPDMA_GLO_CFG, reg);
> > -
> > -	/*
> >  	 * Initialize firmware.
> >  	 */
> >  	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
> 
> This basically seems to be a revert of commit
> 4ed1dd2a7ec880b301beb61cbc1e08811ec340e4 in the wireless-testing tree.
> That commit was submitted by Stanislaw, which basically does the reverse
> of what you are doing here.
> 
> I leave it up to you and Stanislaw to decide on what the state is that
> we need to be in.

When DMA was disabled before FW load, I observed frame receives before
->enable_radio, so looks like WPDMA_GLO_CFG register is overwritten by
F/W load. Although received frames did not make any damage, I prefer
not to allow hw to send data to driver, before driver will be really
ready to receive them.

Stanislaw