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From: Songjun Wu <songjun.wu@linux.intel.com>
To: yixin.zhu@linux.intel.com, chuanhua.lei@linux.intel.com,
	hauke.mehrtens@intel.com
Cc: Songjun Wu <songjun.wu@linux.intel.com>,
	linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paul.burton@mips.com>,
	James Hogan <jhogan@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 05/14] MIPS: lantiq: Unselect SWAP_IO_SPACE when LANTIQ is selected
Date: Mon, 24 Sep 2018 18:27:54 +0800	[thread overview]
Message-ID: <20180924102803.30263-6-songjun.wu@linux.intel.com> (raw)
In-Reply-To: <20180924102803.30263-1-songjun.wu@linux.intel.com>

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>
---

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

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 138d60cf19bc..dcc1fd39cbf3 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -406,7 +406,6 @@ 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
-- 
2.11.0


  parent reply	other threads:[~2018-09-24 10:32 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-24 10:27 [PATCH 00/14] serial: langtiq: Add CCF suppport Songjun Wu
2018-09-24 10:27 ` [PATCH 01/14] MIPS: dts: Change upper case to lower case Songjun Wu
2018-09-24 10:27 ` [PATCH 02/14] MIPS: dts: Add aliases node for lantiq danube serial Songjun Wu
2018-09-24 10:27 ` [PATCH 03/14] serial: lantiq: Get serial id from dts Songjun Wu
2018-09-24 10:27 ` [PATCH 04/14] serial: lantiq: Change ltq_w32_mask to asc_update_bits Songjun Wu
2018-09-24 10:27 ` Songjun Wu [this message]
2018-09-24 10:27 ` [PATCH 06/14] serial: lantiq: Use readl/writel instead of ltq_r32/ltq_w32 Songjun Wu
2018-09-24 10:27 ` [PATCH 07/14] serial: lantiq: Rename fpiclk to freqclk Songjun Wu
2018-09-24 10:27 ` [PATCH 08/14] serial: lantiq: Replace clk_enable/clk_disable with clk generic API Songjun Wu
2018-09-24 10:27 ` [PATCH 09/14] serial: lantiq: Add CCF support Songjun Wu
2018-09-24 10:27 ` [PATCH 10/14] serial: lantiq: Reorder the head files Songjun Wu
2018-09-24 10:28 ` [PATCH 11/14] include: Add lantiq.h in include/linux/ Songjun Wu
2018-09-24 10:28 ` [PATCH 12/14] serial: lantiq: Replace lantiq_soc.h with lantiq.h Songjun Wu
2018-09-24 10:28 ` [PATCH 13/14] serial: lantiq: Change init_lqasc to static declaration Songjun Wu
2018-09-24 10:28 ` [PATCH 14/14] dt-bindings: serial: lantiq: Add optional properties for CCF Songjun Wu
2018-10-15 21:58 ` [PATCH 00/14] serial: langtiq: Add CCF suppport Paul Burton
2018-10-16  9:05   ` Wu, Songjun

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