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From: Tom Rini <trini@ti.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 2/4] cache_v7: Check for dcache enablement in dcache flush functions
Date: Mon, 18 Jun 2012 08:23:27 -0700	[thread overview]
Message-ID: <4FDF47EF.2030103@ti.com> (raw)
In-Reply-To: <CAJ7qFSdWKKcyBvj+DRag3w3B_XUJoTK5uaMu-bsryZUij6PUww@mail.gmail.com>

On 06/18/2012 07:13 AM, R, Sricharan wrote:
> Hi Tom,
> 
> On Fri, Jun 15, 2012 at 8:50 PM, Tom Rini <trini@ti.com> wrote:
>> On 06/15/2012 08:18 AM, R, Sricharan wrote:
>>> Hi,
>>> [snip..]
>>>>>>>    If it is a problem with unaligned regions, then that is the only
>>>>>>> thing to be fixed
>>>>>>>   right ?. Just trying to understand why this change is required ?
>>>>>>
>>>>>> The problem is that within the USB/network/filesystem stacks we have a
>>>>>> lot of not cache safe alignments apparently.  Without this every '#' of
>>>>>> a tftp gives a screen full of error printfs.  So tftp'ing a kernel takes
>>>>>> minutes, not seconds, to complete.
>>>>>>
>>>>>  Ok,but when buffers are not aligned
>>>>>    isn't that you are going to have coherency problems ?
>>>>
>>>> Exactly.  USB requires dcache to be turned off today.  With it turned
>>>> off it spams these messages making tftp to an aligned address take
>>>> minutes because the console is busy printing all of these messages about
>>>> flushes it didn't need to do.  The alternative is to build
>>>> omap4/omap5/etc with dcache disabled or USB disabled.
>>>>
>>>     Ok, but who is calling cache maintenance in your case after
>>>    turning off caches ?
>>
>> The USB stack currently.
> 
>  Ok, in that case if
>  1) Alignment issue has to be fixed USB stack,  (or)

This is the correct, long term solution.

> 2) Better to turn off caches when say USB-EHCI is enabled ?

Doing that is what showed the issue to start with.  Running 'dcache off'
doesn't turn off attempted cache flushing.

>    (or)
> 
> 3) Turn of caches until cache library is fixed so that
>       we will not require any maintenance after turning it off.
>      ( I will work on this some time, this week)

This is also a good thing.  It just needs to make sure attempted flushes
don't spam the console, when cache is off :)

>  I am not sure which one to do, but definitely we should not
>  prevent it from executing as in the above patch. This may
>  lead to other issues.

OK.  I'll see how badly boot time goes up when dcache is off to start
with on a few boards.

-- 
Tom

  reply	other threads:[~2012-06-18 15:23 UTC|newest]

Thread overview: 85+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-14 19:01 [U-Boot] [PATCH 0/4] USB and cache related fixes Tom Rini
2012-06-14 19:01 ` [U-Boot] [PATCH 1/4] ehci-omap: Do not call dcache_off from omap_ehci_hcd_init Tom Rini
2012-06-14 21:57   ` Marek Vasut
2012-06-14 22:14     ` Tom Rini
2012-06-14 19:01 ` [U-Boot] [PATCH 2/4] cache_v7: Check for dcache enablement in dcache flush functions Tom Rini
2012-06-14 22:00   ` Marek Vasut
2012-06-14 22:11     ` Tom Rini
2012-06-14 23:17       ` Marek Vasut
2012-06-15  5:48   ` R, Sricharan
2012-06-15 14:07     ` Tom Rini
2012-06-15 14:25       ` Marek Vasut
2012-06-15 14:30         ` Tom Rini
2012-06-15 14:33           ` Marek Vasut
2012-06-15 14:48       ` R, Sricharan
2012-06-15 15:00         ` Tom Rini
2012-06-15 15:18           ` R, Sricharan
2012-06-15 15:20             ` Tom Rini
2012-06-18 14:13               ` R, Sricharan
2012-06-18 15:23                 ` Tom Rini [this message]
2012-06-20 16:46         ` Aneesh V
2012-06-21  9:25           ` Sricharan R
2012-06-21 15:23             ` R, Sricharan
2012-06-27 23:40               ` Aneesh V
2012-06-28  5:49                 ` R, Sricharan
2012-06-27 23:17             ` Aneesh V
2012-06-14 19:01 ` [U-Boot] [PATCH 3/4] ehci-hcd.c: Add a new USB_DMA_MINALIGN define for cache alignment Tom Rini
2012-06-14 19:29   ` Marek Vasut
2012-06-14 19:30     ` Tom Rini
2012-06-14 19:41       ` Marek Vasut
2012-06-14 19:54         ` Tom Rini
2012-06-14 20:02           ` Marek Vasut
2012-06-14 19:01 ` [U-Boot] [PATCH 4/4] musb_core.h: " Tom Rini
2012-06-14 21:45 ` [U-Boot] [PATCH v2 0/3] USB and cache related fixes Tom Rini
2012-06-14 21:45   ` [U-Boot] [PATCH v2 1/3] ehci-omap: Do not call dcache_off from omap_ehci_hcd_init Tom Rini
2012-06-14 21:45   ` [U-Boot] [PATCH v2 2/3] cache_v7: Check for dcache enablement in dcache flush functions Tom Rini
2012-06-14 21:45   ` [U-Boot] [PATCH v2 3/3] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment Tom Rini
2012-06-20 16:21   ` [U-Boot] [PATCH v3 0/6] USB and cache related fixes Tom Rini
2012-06-20 16:21     ` [U-Boot] [PATCH v3 1/6] ehci-omap: Do not call dcache_off from omap_ehci_hcd_init Tom Rini
2012-06-20 16:21     ` [U-Boot] [PATCH v3 2/6] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment Tom Rini
2012-06-20 19:00       ` Marek Vasut
2012-06-20 19:15         ` Tom Rini
2012-06-20 21:15           ` Marek Vasut
2012-06-20 22:07             ` Tom Rini
2012-06-21  0:09               ` Marek Vasut
2012-06-20 16:21     ` [U-Boot] [PATCH v3 3/6] mcx: Disable DCACHE since USB EHCI is enabled Tom Rini
2012-06-20 16:21     ` [U-Boot] [PATCH v3 4/6] omap3_beagle: " Tom Rini
2012-06-20 16:21     ` [U-Boot] [PATCH v3 5/6] omap4_panda: " Tom Rini
2012-06-20 16:21     ` [U-Boot] [PATCH v3 6/6] tam3517-common: " Tom Rini
2012-06-20 22:14     ` [U-Boot] [PATCH v4 0/6] USB and cache related fixes Tom Rini
2012-06-20 22:14       ` [U-Boot] [PATCH v4 1/6] ehci-omap: Do not call dcache_off from omap_ehci_hcd_init Tom Rini
2012-06-20 22:14       ` [U-Boot] [PATCH v4 2/6] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment Tom Rini
2012-06-20 22:14       ` [U-Boot] [PATCH v4 3/6] mcx: Disable DCACHE since USB EHCI is enabled Tom Rini
2012-06-27 22:28         ` Ilya Yanok
2012-06-27 22:48           ` Marek Vasut
2012-06-28 13:57             ` Ilya Yanok
2012-06-28 14:37               ` Marek Vasut
2012-06-28 14:57                 ` Ilya Yanok
2012-06-28 15:41                   ` Marek Vasut
2012-06-30 15:51                     ` Ilya Yanok
2012-06-30 19:27                       ` Marek Vasut
2012-07-03 20:10                         ` Ilya Yanok
2012-07-03 21:23                           ` Marek Vasut
2012-06-28 17:29                 ` Tom Rini
2012-06-28 22:01                   ` Marek Vasut
2012-06-28 22:34                     ` Tom Rini
2012-06-28 22:36                       ` Marek Vasut
2012-06-28 23:01                         ` Tom Rini
2012-06-29  0:54                           ` Marek Vasut
2012-06-29  2:14                             ` Tom Rini
2012-06-30 15:55                             ` Ilya Yanok
2012-06-30 19:28                               ` Marek Vasut
2012-07-03 20:13                                 ` Ilya Yanok
2012-07-03 20:43                                   ` Tom Rini
2012-07-03 21:12                                     ` Ilya Yanok
2012-07-04  0:14                                       ` Marek Vasut
2012-07-04 13:08                                         ` Ilya Yanok
2012-07-03 21:24                                     ` Marek Vasut
2012-06-20 22:14       ` [U-Boot] [PATCH v4 4/6] omap3_beagle: " Tom Rini
2012-06-20 22:14       ` [U-Boot] [PATCH v4 5/6] omap4_panda: " Tom Rini
2012-06-21 11:19         ` Sricharan R
2012-06-21 16:40           ` R, Sricharan
2012-06-20 22:14       ` [U-Boot] [PATCH v4 6/6] tam3517-common: " Tom Rini
2012-06-14 22:02 ` [U-Boot] [PATCH 0/4] USB and cache related fixes Marek Vasut
2012-06-14 22:13   ` Tom Rini
2012-06-14 23:17     ` Marek Vasut

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