Re: [PATCH v2 1/5] arm: mach-k3: common: Reserve video memory from end of the RAM

Devarsh Thakkar
2023-11-08T12:57:06Z

Hi Simon,

Thanks for the review.

On 05/11/23 01:13, Simon Glass wrote:
> Hi Devarsh,
>
> On Fri, 3 Nov 2023 at 11:48, Devarsh Thakkar <devarsht@ti.com> wrote:
>>
>> Hi Simon,
>>
>> Thanks for the review.
>>
>> On 03/11/23 04:16, Simon Glass wrote:
>>> Hi Devarsh,
>>>
>>> On Tue, 31 Oct 2023 at 13:12, Devarsh Thakkar <devarsht@ti.com> wrote:
>>>>
>>>> Add function spl_reserve_video which is a wrapper
>>>> around video_reserve to setup video memory and update
>>>> the relocation address pointer.
>>>>
>>>> Setup video memory before page table reservation so that
>>>> framebuffer memory gets reserved from the end of RAM.
>>>>
>>>> This is as per the new policy being discussed for passing
>>>> blobs where each of the reserved areas for bloblists
>>>> to be passed need to be reserved at the end of RAM.
>>>>
>>>> This is done to enable the next stage to directly skip
>>>> the pre-reserved area from previous stage right from the end of RAM
>>>> without having to make any gaps/holes to accommodate those
>>>> regions which was the case before as previous stage
>>>> reserved region not from the end of RAM.
>>>>
>>>> Suggested-by: Simon Glass <sjg@chromium.org>
>>>> Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
>>>> ---
>>>> V2: Make a generic function "spl_reserve_video" under
>>>> common/spl which can be re-used by other platforms too
>>>> for reserving video memory from spl.
>>>> ---
>>>> arch/arm/mach-k3/common.c | 2 ++
>>>> common/spl/spl.c | 19 +++++++++++++++++++
>>>> include/spl.h | 4 ++++
>>>> 3 files changed, 25 insertions(+)
>>>
>>>>
>>>> diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
>>>> index c3006ba387..03e3b46282 100644
>>>> --- a/arch/arm/mach-k3/common.c
>>>> +++ b/arch/arm/mach-k3/common.c
>>>> @@ -537,6 +537,8 @@ void spl_enable_dcache(void)
>>>> if (ram_top >= 0x100000000)
>>>> ram_top = (phys_addr_t) 0x100000000;
>>>>
>>>> + gd->relocaddr = ram_top;
>>>> + spl_reserve_video();
>>>
>>> Need to check error here
>>>
>>
>> Ok, I can check for error and print a message, but would still proceed
>> with build (similar to reserve_video in u-boot proper (from which this
>> is derived)), I hope that is fine.
>
> No, we need to fail if something is wrong.
>

Yes the caller of the function is having void return value so can't propagate
it but I can still do a exit or hang. But besides this the API as such returns
the success/failure and it is left upto user to decide. As the user in this
case is TI (mack-k3) the previous behavior was preserved where it proceed with
boot on video reservation failure, I guess I will check again with more folks
here at TI and based on that take a decision.

>>
>>>> gd->arch.tlb_addr = ram_top - gd->arch.tlb_size;
>>>> gd->arch.tlb_addr &= ~(0x10000 - 1);
>>>> debug("TLB table from %08lx to %08lx\n", gd->arch.tlb_addr,
>>>> diff --git a/common/spl/spl.c b/common/spl/spl.c
>>>> index 732d90d39e..89172f2ebf 100644
>>>> --- a/common/spl/spl.c
>>>> +++ b/common/spl/spl.c
>>>> @@ -41,6 +41,7 @@
>>>> #include <fdt_support.h>
>>>> #include <bootcount.h>
>>>> #include <wdt.h>
>>>> +#include <video.h>
>>>>
>>>> DECLARE_GLOBAL_DATA_PTR;
>>>> DECLARE_BINMAN_MAGIC_SYM;
>>>> @@ -151,6 +152,24 @@ void spl_fixup_fdt(void *fdt_blob)
>>>> #endif
>>>> }
>>>>
>>>> +int spl_reserve_video(void)
>>>> +{
>>>> + if (CONFIG_IS_ENABLED(VIDEO)) {
>>>> + ulong addr;
>>>> + int ret;
>>>> +
>>>> + addr = gd->relocaddr;
>>>> + ret = video_reserve(&addr);
>>>> + if (ret)
>>>> + return ret;
>>>> + debug("Reserving %luk for video at: %08lx\n",
>>>> + ((unsigned long)gd->relocaddr - addr) >> 10, addr);
>>>> + gd->relocaddr = addr;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> ulong spl_get_image_pos(void)
>>>> {
>>>> if (!CONFIG_IS_ENABLED(BINMAN_UBOOT_SYMBOLS))
>>>> diff --git a/include/spl.h b/include/spl.h
>>>> index 0d49e4a454..9682e51fc1 100644
>>>> --- a/include/spl.h
>>>> +++ b/include/spl.h
>>>> @@ -825,6 +825,10 @@ int spl_usb_load(struct spl_image_info *spl_image,
>>>>
>>>> int spl_ymodem_load_image(struct spl_image_info *spl_image,
>>>> struct spl_boot_device *bootdev);
>>>> +/**
>>>> + * spl_reserve_video() - Reserve video and update relocation address
>>>
>>> This needs more detail about:
>>> - gd->relocaddr
>>
>> Points to current relocation address which points to region below
>> reserved area ?
>>
>>> - where the video memory is allocated
>> I didn't get you, allocation is stored in RAM, is that what you mean ?
>
> Yes, but specifically at the top of RAM, I believe?
>
>>
>>> - where the allocation is stored (in the video-device plat?)ok
>>
>>> - return value
>>>
>>
>> Just a point of note, this spl_reserve_video is inspired by
>> reserve_video from u-boot proper and we are essentially leaving upto
>> users to follow the "guideline" to reserve video from RAM by setting
>> gd->relocaddr to end of RAM before calling to function.
>>
>> But if we want to directly enforce the guideline, I can move that logic
>> inside this API and we can have spl_reserve_video_from_ramtop, let me
>> know your opinion on this if we want to go this way.
>
> That seems OK to me, so far as I understand what you are saying.
>

Ok, will make it spl_video_reserve_from_ram_top, thanks!.

Regards
Devarsh

> [..]
>
> Regards,
> Simon