Hi Rafael,


On 14 July 2016 at 05:43, Rafael J. Wysocki [off-list ref] wrote:

On Wed, Jul 13, 2016 at 11:08 PM, Guenter Roeck [off-list ref] wrote:

quoted

On Wed, Jul 13, 2016 at 10:30:37PM +0200, Rafael J. Wysocki wrote:

quoted

On Wed, Jul 13, 2016 at 7:53 PM,  [off-list ref] wrote:

quoted

From: Fu Wei <redacted>

This patch adds support for parsing arch timer in GTDT,
provides some kernel APIs to parse all the PPIs and
always-on info in GTDT and export them.

By this driver, we can simplify arm_arch_timer drivers, and
separate the ACPI GTDT knowledge from it.

Signed-off-by: Fu Wei <redacted>
Signed-off-by: Hanjun Guo <redacted>
---
 drivers/acpi/Kconfig           |   5 ++
 drivers/acpi/Makefile          |   1 +
 drivers/acpi/arm64/Kconfig     |  15 ++++
 drivers/acpi/arm64/Makefile    |   1 +
 drivers/acpi/arm64/acpi_gtdt.c | 170 +++++++++++++++++++++++++++++++++++++++++
 include/linux/acpi.h           |   6 ++
 6 files changed, 198 insertions(+)

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index b7e2e77..1cdc7d2 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig

@@ -521,4 +521,9 @@ config XPOWER_PMIC_OPREGION

 endif

+if ARM64
+source "drivers/acpi/arm64/Kconfig"
+
+endif
+
 endif  # ACPI

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 251ce85..1a94ff7 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile

@@ -99,5 +99,6 @@ obj-$(CONFIG_ACPI_EXTLOG)     += acpi_extlog.o
 obj-$(CONFIG_PMIC_OPREGION)    += pmic/intel_pmic.o
 obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
 obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
+obj-$(CONFIG_ARM64)    += arm64/

 video-objs                     += acpi_video.o video_detect.o

diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
new file mode 100644
index 0000000..ff5c253
--- /dev/null
+++ b/drivers/acpi/arm64/Kconfig

@@ -0,0 +1,15 @@
+#
+# ACPI Configuration for ARM64
+#
+
+menu "The ARM64-specific ACPI Support"
+
+config ACPI_GTDT
+       bool "ACPI GTDT table Support"

This should depend on ARM64.

Also I wonder if it needs to be user-selectable?  Wouldn't it be
better to enable it by default when building for ARM64 with ACPI?

It is currently selected in patch 9, in the watchdog driver's Kconfig
entry.

Well, it still doesn't have to be user-selectable for that. :-)

Actually it is also automatically selected by [PATCH v7 6/9]:

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 47352d2..71d5b30 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig

@@ -8,6 +8,7 @@ config CLKSRC_OF
 config CLKSRC_ACPI
  bool
  select CLKSRC_PROBE
+ select ACPI_GTDT if ARM64

 config CLKSRC_PROBE
  bool

quoted

Not sure if I like that; maybe the watchdog driver should depend
on it instead ?

If the watchdog is not the only user of it (and I don't think it is),
it would be better to arrange things this way.

There are two user:
(1) arm_arch_timer(which will select CLKSRC_ACPI if ACPI, then
CLKSRC_ACPI will select ACPI_GTDT if ARM64)
So arm_arch_timer will automatically selecte ACPI_GTDT if ARM64 && ACPI

(2) sbsa_gwdt (which will select ACPI_GTDT if ACPI in [PATCH v7 9/9])
So sbsa_gwdt will automatically selecte ACPI_GTDT if ARM64 && ACPI &&
ARM_ARCH_TIMER

So ACPI_GTDT is automatically selected by both of two users.


But like Timur said before:

maybe we just "selecte ACPI_GTDT if ACPI" for ARM64, because ARM64
require GTDT if we use ACPI.

Thanks,
Rafael

-- 
Best regards,

Fu Wei
Software Engineer
Red Hat