[PATCH 1/1] Add config option for batched hcalls

[Will Schmidt]

Add a config option for the (batched) MULTITCE and BULK_REMOVE h-calls.

By default, these options are on and are beneficial for performance and
throughput reasons.   If disabled, the code will fall back to using less
optimal TCE and REMOVE hcalls.   The ability to easily disable these
options is useful for some of the PREEMPT_RT related investigation and
work occurring on Power.


Signed-off-by: Will Schmidt <will_schmidt at vnet.ibm.com>
cc: Anton Blanchard <anton at samba.org>
cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>

---
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index f0e6f28..0b5e6a9 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -81,3 +81,23 @@ config DTL
 	  which are accessible through a debugfs file.
 
 	  Say N if you are unsure.
+
+config BULK_REMOVE
+	bool "Enable BULK_REMOVE"
+	depends on PPC_PSERIES
+	default y
+	help
+	  Enable the BULK_REMOVE option for the hash page code.
+	  This relies on a "hcall-bulk" firmware feature, and
+	  should be enabled for performance throughput.
+
+config MULTITCE
+	bool "Enable MultiTCE"
+	depends on PPC_PSERIES
+	default y
+	help
+	  Enable the Multi-TCE code, allowing a single hcall to
+	  update multiple TCE entries at one time.  This relies
+	  on a "hcall-multi-tce" firmware feature, and should be
+	  enabled for performance throughput.
+
diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
index 0a4d8c..4327064 100644
--- a/arch/powerpc/platforms/pseries/firmware.c
+++ b/arch/powerpc/platforms/pseries/firmware.c
@@ -51,9 +51,13 @@ firmware_features_table[FIRMWARE_MAX_FEATURES] = {
 	{FW_FEATURE_VIO,		"hcall-vio"},
 	{FW_FEATURE_RDMA,		"hcall-rdma"},
 	{FW_FEATURE_LLAN,		"hcall-lLAN"},
+#if defined(CONFIG_BULK_REMOVE)
 	{FW_FEATURE_BULK_REMOVE,	"hcall-bulk"},
+#endif
 	{FW_FEATURE_XDABR,		"hcall-xdabr"},
+#if defined(CONFIG_MULTITCE)
 	{FW_FEATURE_MULTITCE,		"hcall-multi-tce"},
+#endif
 	{FW_FEATURE_SPLPAR,		"hcall-splpar"},
 };
 
 /* Build up the firmware features bitmask using the contents of