[v2,10/18] MIPS: lantiq: Unselect SWAP_IO_SPACE when LANTIQ is selected
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Message ID 20180803030237.3366-11-songjun.wu@linux.intel.com
State Not Applicable, archived
Headers show
Series
  • MIPS: intel: add initial support for Intel MIPS SoCs
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Commit Message

Wu, Songjun Aug. 3, 2018, 3:02 a.m. UTC
SWAP_IO_SPACE macro prevents serial driver /drivers/tty/serial/lantiq.c
to use readl/writel to replace ltq_r32/w32 which are SoC or platform
specific APIs.

readl/writel are used for this serial driver to support multiple
platforms and multiple architectures. The legacy lantiq platform(Danube)
enables SWAP_IO_SPACE for supporting PCI due to some hardware bugs.

It's a little-endian bus plus PCI TX/RX swap enable impacted both data
and control path for MIPS based platforms. But it is better to let PCI
device driver to do endian swap since SWAP_IO_SPACE is a global wide macro
which potentially impacts other peripheral like USB.
ltq_r32/ltq_w32 is not impacted in other device drivers based on MIPS when
SWAP_IO_SPACE is not selected as they use non-byte swapping OS API
(__raw_read/__raw_writel).

Signed-off-by: Songjun Wu <songjun.wu@linux.intel.com>
---

Changes in v2: None

 arch/mips/Kconfig | 1 -
 1 file changed, 1 deletion(-)

Patch
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diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 2d34f17f3e24..2e7e0b538e52 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -400,7 +400,6 @@  config LANTIQ
 	select SYS_SUPPORTS_VPE_LOADER
 	select SYS_HAS_EARLY_PRINTK
 	select GPIOLIB
-	select SWAP_IO_SPACE
 	select BOOT_RAW
 	select CLKDEV_LOOKUP
 	select USE_OF