Re: [PATCH] usb: host: Add a quirk for writing ERST in high-low order

[Greg Kroah-Hartman]

On Tue, May 28, 2024 at 09:23:43AM +0200, Greg Kroah-Hartman wrote:
> On Tue, May 28, 2024 at 02:57:16PM +0900, Daehwan Jung wrote:
> > [Synopsys]- The host controller was design to support ERST setting
> > during the RUN state. But since there is a limitation in controller
> > in supporting separate ERSTBA_HI and ERSTBA_LO programming,
> > It is supported when the ERSTBA is programmed in 64bit,
> > or in 32 bit mode ERSTBA_HI before ERSTBA_LO
> > 
> > [Synopsys]- The internal initialization of event ring fetches
> > the "Event Ring Segment Table Entry" based on the indication of
> > ERSTBA_LO written.
> > 
> > Signed-off-by: Daehwan Jung <dh10.jung@xxxxxxxxxxx>
> > ---
> >  drivers/usb/host/xhci-mem.c | 5 ++++-
> >  drivers/usb/host/xhci.h     | 2 ++
> >  2 files changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> > index 3100219..ef768e6 100644
> > --- a/drivers/usb/host/xhci-mem.c
> > +++ b/drivers/usb/host/xhci-mem.c
> > @@ -2325,7 +2325,10 @@ xhci_add_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir,
> >  	erst_base = xhci_read_64(xhci, &ir->ir_set->erst_base);
> >  	erst_base &= ERST_BASE_RSVDP;
> >  	erst_base |= ir->erst.erst_dma_addr & ~ERST_BASE_RSVDP;
> > -	xhci_write_64(xhci, erst_base, &ir->ir_set->erst_base);
> > +	if (xhci->quirks & XHCI_WRITE_64_HI_LO)
> > +		hi_lo_writeq(erst_base, &ir->ir_set->erst_base);
> > +	else
> > +		xhci_write_64(xhci, erst_base, &ir->ir_set->erst_base);
> >  
> >  	/* Set the event ring dequeue address of this interrupter */
> >  	xhci_set_hc_event_deq(xhci, ir);
> > diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> > index 3041515..8664dd1 100644
> > --- a/drivers/usb/host/xhci.h
> > +++ b/drivers/usb/host/xhci.h
> > @@ -17,6 +17,7 @@
> >  #include <linux/kernel.h>
> >  #include <linux/usb/hcd.h>
> >  #include <linux/io-64-nonatomic-lo-hi.h>
> > +#include <linux/io-64-nonatomic-hi-lo.h>

Why not put this in the .c file?

> >  /* Code sharing between pci-quirks and xhci hcd */
> >  #include	"xhci-ext-caps.h"
> > @@ -1627,6 +1628,7 @@ struct xhci_hcd {
> >  #define XHCI_RESET_TO_DEFAULT	BIT_ULL(44)
> >  #define XHCI_ZHAOXIN_TRB_FETCH	BIT_ULL(45)
> >  #define XHCI_ZHAOXIN_HOST	BIT_ULL(46)
> > +#define XHCI_WRITE_64_HI_LO	BIT_ULL(47)

Note, you define this, and check it, but it is never set, so this patch
is useless on its own and so we can not accept it as-is at all.

How was this tested?

thanks,

greg k-h