[PATCH v3 2/3] MIPS: SiByte: Enable ZONE_DMA32 for LittleSur

From: Maciej W. Rozycki
Date: Tue Nov 13 2018 - 17:44:17 EST


The LittleSur board is marked for high memory support and therefore
clearly must provide a way to have enough memory installed for some to
be present outside the low 4GiB physical address range. With the memory
map of the BCM1250 SOC it has been built around it means over 1GiB of
actual DRAM, as only the first 1GiB is mapped in the low 4GiB physical
address range[1].

Complement commit cce335ae47e2 ("[MIPS] 64-bit Sibyte kernels need
DMA32.") then and also enable ZONE_DMA32 for LittleSur.

References:

[1] "BCM1250/BCM1125/BCM1125H User Manual", Revision 1250_1125-UM100-R,
Broadcom Corporation, 21 Oct 2002, Section 3: "System Overview",
"Memory Map", pp. 34-38

Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx>
Fixes: cce335ae47e2 ("[MIPS] 64-bit Sibyte kernels need DMA32.")
---
New in v3.
---
arch/mips/Kconfig | 1 +
1 file changed, 1 insertion(+)

linux-mips-sibyte-littlesur-zone-dma32.diff
Index: linux-20181104-littlesur64-defconfig/arch/mips/Kconfig
===================================================================
--- linux-20181104-littlesur64-defconfig.orig/arch/mips/Kconfig
+++ linux-20181104-littlesur64-defconfig/arch/mips/Kconfig
@@ -805,6 +805,7 @@ config SIBYTE_LITTLESUR
select SYS_SUPPORTS_BIG_ENDIAN
select SYS_SUPPORTS_HIGHMEM
select SYS_SUPPORTS_LITTLE_ENDIAN
+ select ZONE_DMA32 if 64BIT

config SIBYTE_SENTOSA
bool "Sibyte BCM91250E-Sentosa"