[PATCH] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G

[PATCH] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G

[E Shattow]

Platform drivers and hardware for StarFive JH-7110 SoC are not capable of
DMA access above 4GB. This was previously a problem for MMC access then
resolved by a workaround, since reverted in a3075db94d49 ("lmb: Reinstate
access to memory above ram_top"). The symptom of this is EFI boot failure
of GRUB from EFI System Partition on USB MSC with a starfive_visionfive2
board target that has the on-chip Cadence USB, tested with Pine64 Star64.

Restore the workaround with a dependency on LMB_LIMIT_DMA_BELOW_RAM_TOP.

Signed-off-by: E Shattow <e@freeshell.de>
---
 lib/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig b/lib/Kconfig
index 6b6b90bc915c..4bb120c97cbd 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -1314,7 +1314,7 @@ config SPL_LMB_ARCH_MEM_MAP
 config LMB_LIMIT_DMA_BELOW_RAM_TOP
 	bool
 	depends on LMB
-	default y if ARCH_BCM283X || ARCH_ROCKCHIP
+	default y if ARCH_BCM283X || ARCH_ROCKCHIP || STARFIVE_JH7110
 	help
 	  Some architectures can not DMA above ram_top boundary,
 	  which is after 4 GiB or 32-bit boundary too. Limit the

base-commit: 369d71b895bc5ce94556d43f05ef9d20084af0d5
-- 
2.53.0

Re: [PATCH] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G

[Marek Vasut]

On 9/30/26 1:07 AM, E Shattow wrote:
> Platform drivers and hardware for StarFive JH-7110 SoC are not capable of
> DMA access above 4GB

4 GiB

>. This was previously a problem for MMC access then
> resolved by a workaround, since reverted in a3075db94d49 ("lmb: Reinstate
> access to memory above ram_top"). The symptom of this is EFI boot failure
> of GRUB from EFI System Partition on USB MSC with a starfive_visionfive2
> board target that has the on-chip Cadence USB, tested with Pine64 Star64.
> 
> Restore the workaround with a dependency on LMB_LIMIT_DMA_BELOW_RAM_TOP.
> 
> Signed-off-by: E Shattow <e@freeshell.de>

Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Re: [PATCH] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G

[E Shattow]

Hi,

On 9/29/26 17:43, Marek Vasut wrote:
> On 9/30/26 1:07 AM, E Shattow wrote:
>> Platform drivers and hardware for StarFive JH-7110 SoC are not capable of
>> DMA access above 4GB
> 
> 4 GiB

Yes, I agree.

> 
>> . This was previously a problem for MMC access then
>> resolved by a workaround, since reverted in a3075db94d49 ("lmb: Reinstate
>> access to memory above ram_top"). The symptom of this is EFI boot failure
>> of GRUB from EFI System Partition on USB MSC with a starfive_visionfive2
>> board target that has the on-chip Cadence USB, tested with Pine64 Star64.
>>
>> Restore the workaround with a dependency on LMB_LIMIT_DMA_BELOW_RAM_TOP.
>>
>> Signed-off-by: E Shattow <e@freeshell.de>
> 
> Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Looks good to me as suggested.

Thanks,  -E

Re: [PATCH] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G

[Tom Rini]

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On Tue, Sep 29, 2026 at 06:51:24PM -0700, E Shattow wrote:
> Hi,
> 
> On 9/29/26 17:43, Marek Vasut wrote:
> > On 9/30/26 1:07 AM, E Shattow wrote:
> >> Platform drivers and hardware for StarFive JH-7110 SoC are not capable of
> >> DMA access above 4GB
> > 
> > 4 GiB
> 
> Yes, I agree.

Fixing as I apply.

> 
> > 
> >> . This was previously a problem for MMC access then
> >> resolved by a workaround, since reverted in a3075db94d49 ("lmb: Reinstate
> >> access to memory above ram_top"). The symptom of this is EFI boot failure
> >> of GRUB from EFI System Partition on USB MSC with a starfive_visionfive2
> >> board target that has the on-chip Cadence USB, tested with Pine64 Star64.
> >>
> >> Restore the workaround with a dependency on LMB_LIMIT_DMA_BELOW_RAM_TOP.
> >>
> >> Signed-off-by: E Shattow <e@freeshell.de>
> > 
> > Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> 
> Looks good to me as suggested.
> 
> Thanks,  -E
> 
> 

-- 
Tom

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Re: [PATCH] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G

[Tom Rini]

On Tue, 29 Sep 2026 16:07:50 -0700, E Shattow wrote:

> Platform drivers and hardware for StarFive JH-7110 SoC are not capable of
> DMA access above 4GB. This was previously a problem for MMC access then
> resolved by a workaround, since reverted in a3075db94d49 ("lmb: Reinstate
> access to memory above ram_top"). The symptom of this is EFI boot failure
> of GRUB from EFI System Partition on USB MSC with a starfive_visionfive2
> board target that has the on-chip Cadence USB, tested with Pine64 Star64.
> 
> [...]

Applied to u-boot/main, thanks!

[1/1] lmb: Add StarFive JH-7110 SoC as requiring DMA below 4G
      (no commit info)
-- 
Tom