Hi Chin,
On 23.03.2016 16:00, Chin Liang See wrote:
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);
I can't really comment on the USB problem, as I've only seen this d-cache / S-bit problem with SPI NOR flash. This is because I've never really used USB on this platform intensively. But I'm nearly 100% sure, that all changes that add some delays (or debug printfs) resulting in a "working solution", either in the USB case or the SPI NOR case, are just papering over the real problem.
Thanks, Stefan