Hi Dmitry,
Suggest you first get internal specifications via official routes (I have no
authority to distribute it) and then propose patches which wouldn't break
existing exynos4210 model.
Thanks,
Dmitry Solodkiy,
Emulator/Kernel PL, Mobile Group,
Moscow R&D center, Samsung Electronics
-----Original Message-----
From: Dmitry Zhurikhin [mailto:z...@ispras.ru]
Sent: Wednesday, April 04, 2012 9:38 PM
To: Maksim Kozlov
Cc: Kyungmin Park; Igor Mitsyanko; qemu-devel@nongnu.org; Evgeny Voevodin;
Dmitry Solodkiy
Subject: Re: [PATCH] Support system reset in Exynos4210
On 2012-04-04 20:16, Maksim Kozlov wrote:
> 04.04.2012 16:35, Dmitry Zhurikhin пишет:
>> On 2012-04-04 15:55, Maksim Kozlov wrote:
>>> 04.04.2012 14:08, Dmitry Zhurikhin пишет:
>>>> Reset the system when 1 is written to SWRESET register
>>>>
>>>> Signed-off-by: Dmitry Zhurikhin<z...@ispras.ru>
>>>> ---
>>>> hw/exynos4210_pmu.c | 11 +++++++++++
>>>> 1 files changed, 11 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/hw/exynos4210_pmu.c b/hw/exynos4210_pmu.c index
>>>> c12d750..edf6e34 100644
>>>> --- a/hw/exynos4210_pmu.c
>>>> +++ b/hw/exynos4210_pmu.c
>>>> @@ -25,6 +25,7 @@
>>>> */
>>>>
>>>> #include "sysbus.h"
>>>> +#include "sysemu.h"
>>>>
>>>> #ifndef DEBUG_PMU
>>>> #define DEBUG_PMU 0
>>>> @@ -422,6 +423,16 @@ static void exynos4210_pmu_write(void *opaque,
>>>> target_phys_addr_t offset,
>>>> if (reg_p->offset == offset) {
>>>> PRINT_DEBUG_EXTEND("%s<0x%04x> <- 0x%04x\n",
>>>> reg_p->name,
>>>> (uint32_t)offset, (uint32_t)val);
>>>> + switch (offset) {
>>>> + case SWRESET:
>>>> + if (val& 1) {
>>>> + qemu_system_reset_request();
>>>> + }
>>>> + break;
>>>> + default:
>>>> + /* Nothing */
>>>> + break;
>>>> + }
>>>> s->reg[i] = val;
>>>> return;
>>>> }
>>> It's not quite well. At first, when you do reset, appropriate status
>>> must be set in RST_STAT register. At second, not all registers in
>>> PMU should be set in default value after reset, so you should change
>>> PMU reset function for handling different resets (see spec) So, this
>>> functionality should be wrote more carefully
>> Well, this is the case when there is a need to modify booting
>> procedure depending on the values of these registers. I haven't
>> found any such code in the current kernel. As I now remember saving
>> their values was indeed important when we were trying to use an
>> U-Boot bootloader. But as long as we are sticking with QEMU bootloader it
>> doesn't matter.
>
> 3.4-rc1 and 2.6.36 kernels use INFORM5 register which should keep his
> value during sw reset. And U-Boot (which can be used instead of kernel
> for some purposes) uses INFORM[456] registers which should be saved as
> well.
>
> My opinion is we should not add code which describe incorrect behavior
> of the device regardless of whether kernel uses some registers or no.
OK, this is a righteous position. Again, I think in this case implementing
what you propose won't be neither bad nor good. But since you've asked, I'll
try to do it.
>
>> Anyway this information is unfortunately absent in Exynos4210 public
>> documentation.
> Hm... Really, I've just found out that public specification doesn't
> contain information about PMU
I can make the changes according to Exynos3210 specification since they are
pretty close. But of course I'd prefer that you send me full specifications.
Dmitry, what you say?
>>>
>>> And use #define for registers and fields of the registers. It's more
>>> clearly, as for me.
>> As you say.
> :)
>>>
>>> Regards,
>>> MK
>>
>> Regards,
>> Dmitry
>>
>>
>
Regards,
Dmitry
