[U-Boot] Newbie SPL question for socfpga_sockit

[Chin Liang See <clsee@altera.com>]

On Mon, 2016-03-21 at 23:45 +0800, Chin Liang See wrote:
> On Mon, 2016-03-21 at 22:05 +0800, Chin Liang See wrote:
> > On Fri, 2016-03-04 at 20:03 +0100, Marek Vasut wrote:
> > > On 03/04/2016 05:06 PM, Dinh Nguyen wrote:
> > > > On 03/02/2016 05:24 PM, Marek Vasut wrote:

[..]

> > > > > Well, that's our usual USB/QSPI cache issue that's tormenting
> > > > > your soul.
> > > > > CCing Chin ;-)
> > > > > 
> > > > > Does the issue by any chance magically disappear if you apply
> > > > > this patch:
> > > > > 
> > > > > diff --git a/arch/arm/include/asm/system.h
> > > > > b/arch/arm/include/asm/system.h
> > > > > index 026e7ef..06802c6 100644
> > > > > --- a/arch/arm/include/asm/system.h
> > > > > +++ b/arch/arm/include/asm/system.h
> > > > > @@ -274,7 +274,7 @@ static inline void set_dacr(unsigned int
> > > > > val)
> > > > > 
> > > > >  /* options available for data cache on each page */
> > > > >  enum dcache_option {
> > > > > -       DCACHE_OFF = TTB_SECT_DOMAIN(0) | TTB_SECT_XN_MASK |
> > > > > TTB_SECT,
> > > > > +       DCACHE_OFF = TTB_SECT_S_MASK | TTB_SECT_DOMAIN(0) |
> > > > > TTB_SECT_XN_MASK | TTB_SECT,
> > > > >         DCACHE_WRITETHROUGH = DCACHE_OFF | TTB_SECT_C_MASK,
> > > > >         DCACHE_WRITEBACK = DCACHE_WRITETHROUGH |
> > > > > TTB_SECT_B_MASK,
> > > > >         DCACHE_WRITEALLOC = DCACHE_WRITEBACK |
> > > > > TTB_SECT_TEX(1),
> > > > > 
> > > > 
> > > > Yes, this patch fixes USB with dcache left on.
> > > 
> > > Except that it doesn't fix anything, it just makes the system
> > > slower
> > > by
> > > setting the S bit :-/ So this is not a fix :-(
> > 
> > Sorry for away for a while as busy with some critical issues. 
> > 
> > Finally relooking back on this. I notice that with SanDisk Cruzer
> > Blade
> > pendrive, U-Boot 2013.01.01 can detect it while latest cannot. The
> > dcache disablement at latest U-Boot doesn't help.
> > 
> > With that, I compared a bunch of registers from clocks, sysmgr,
> > SCTLR,
> > ATCLR and USB1 too. I noticed they are similar except the
> > usb1.globgrp.gusbcfg.ulpiextvbusdrv. The latest U-Boot is
> > indicating
> > external supply (address 0xffb4000c return value 0x00101710) while
> > working 2013.01.01 indicating internal charge pump (return value
> > 0x00001710)
> > 
> > Wonder you guys are seeing the same too? Will dig more about this.
> > FYI,
> > I tried to add lot of delay within dwc2.c but doesn't help at all.
> > 
> 
> While modifying the USB power control of the code, I noticed the
> patch
> made by Dinh is not there. Just realize the git clone through http
> from
> main git doesn't work. I was able to clone but getting older version.
> 
> With getting the latest code, all my pendrive now can works with
> dcache
> off. Its easier now as I can get consistent behaviour compared
> previously. With that, dcache investigation for tomorrow then
> 
> Thanks
> Chin Liang
> 

Spent more time on the dcache + USB issue today. Narrow down to below
patch which can make all my USB pendrives work with dcache enabled. But
still need to understand further as not in depth familiar with dwc2.
Probably this might ring a bell to you guys?


diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
index b2f4bc6..b11d8d7 100644
--- a/drivers/usb/host/dwc2.c
+++ b/drivers/usb/host/dwc2.c
@@ -776,6 +776,7 @@ static int transfer_chunk(struct dwc2_hc_regs
*hc_regs, void *aligned_buffer,
               (num_packets << DWC2_HCTSIZ_PKTCNT_OFFSET) |
               (*pid << DWC2_HCTSIZ_PID_OFFSET),
               &hc_regs->hctsiz);
+       udelay(2);

        if (!in && xfer_len) {
                memcpy(aligned_buffer, buffer, xfer_len);


Thanks
Chin Liang

> 
> > Thanks
> > Chin Liang
> > 
> > 
> > 
> > >