interconnect: qcom: fix rpmh link failures

From: Arnd Bergmann <[email protected]>

When CONFIG_COMPILE_TEST is set, it is possible to build some of the interconnect drivers into the kernel while their dependencies are loadable modules, which is bad:

arm-linux-gnueabi-ld: drivers/interconnect/qcom/bcm-voter.o: in function `qcom_icc_bcm_voter_commit':
(.text+0x1f8): undefined reference to `rpmh_invalidate'
arm-linux-gnueabi-ld: (.text+0x20c): undefined reference to `rpmh_write_batch'
arm-linux-gnueabi-ld: (.text+0x2b0): undefined reference to `rpmh_write_batch'
arm-linux-gnueabi-ld: (.text+0x2e8): undefined reference to `rpmh_write_batch'
arm-linux-gnueabi-ld: drivers/interconnect/qcom/icc-rpmh.o: in function `qcom_icc_bcm_init':
(.text+0x2ac): undefined reference to `cmd_db_read_addr'
arm-linux-gnueabi-ld: (.text+0x2c8): undefined reference to `cmd_db_read_aux_data'

The exact dependencies are a bit complicated, so split them out into a hidden Kconfig symbol that all drivers can in turn depend on to get it right.

Fixes 976daac4a1c5 ("interconnect: qcom: Consolidate interconnect RPMh support")

Signed-off-by Arnd Bergmann <[email protected]>

---
 drivers/interconnect/qcom/Kconfig | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

drivers/interconnect/qcom/Kconfig +15 -8

index a8f93ba265f8..b3fb5b02bcf1 100644
@@ -42,13 +42,23 @@ config INTERCONNECT_QCOM_QCS404
 	  This is a driver for the Qualcomm Network-on-Chip on qcs404-based
 	  platforms.
 
+config INTERCONNECT_QCOM_RPMH_POSSIBLE
+	tristate
+	default INTERCONNECT_QCOM
+	depends on QCOM_RPMH || (COMPILE_TEST && !QCOM_RPMH)
+	depends on QCOM_COMMAND_DB || (COMPILE_TEST && !QCOM_COMMAND_DB)
+	depends on OF || COMPILE_TEST
+	help
+	  Compile-testing RPMH drivers is possible on other platforms,
+	  but in order to avoid link failures, drivers must not be built-in
+	  when QCOM_RPMH or QCOM_COMMAND_DB are loadable modules
+
 config INTERCONNECT_QCOM_RPMH
 	tristate
 
 config INTERCONNECT_QCOM_SC7180
 	tristate "Qualcomm SC7180 interconnect driver"
-	depends on INTERCONNECT_QCOM
-	depends on (QCOM_RPMH && QCOM_COMMAND_DB && OF) || COMPILE_TEST
+	depends on INTERCONNECT_QCOM_RPMH_POSSIBLE
 	select INTERCONNECT_QCOM_RPMH
 	select INTERCONNECT_QCOM_BCM_VOTER
 	help

@@ -57,8 +67,7 @@ config INTERCONNECT_QCOM_SC7180
 
 config INTERCONNECT_QCOM_SDM845
 	tristate "Qualcomm SDM845 interconnect driver"
-	depends on INTERCONNECT_QCOM
-	depends on (QCOM_RPMH && QCOM_COMMAND_DB && OF) || COMPILE_TEST
+	depends on INTERCONNECT_QCOM_RPMH_POSSIBLE
 	select INTERCONNECT_QCOM_RPMH
 	select INTERCONNECT_QCOM_BCM_VOTER
 	help

@@ -67,8 +76,7 @@ config INTERCONNECT_QCOM_SDM845
 
 config INTERCONNECT_QCOM_SM8150
 	tristate "Qualcomm SM8150 interconnect driver"
-	depends on INTERCONNECT_QCOM
-	depends on (QCOM_RPMH && QCOM_COMMAND_DB && OF) || COMPILE_TEST
+	depends on INTERCONNECT_QCOM_RPMH_POSSIBLE
 	select INTERCONNECT_QCOM_RPMH
 	select INTERCONNECT_QCOM_BCM_VOTER
 	help

@@ -77,8 +85,7 @@ config INTERCONNECT_QCOM_SM8150
 
 config INTERCONNECT_QCOM_SM8250
 	tristate "Qualcomm SM8250 interconnect driver"
-	depends on INTERCONNECT_QCOM
-	depends on (QCOM_RPMH && QCOM_COMMAND_DB && OF) || COMPILE_TEST
+	depends on INTERCONNECT_QCOM_RPMH_POSSIBLE
 	select INTERCONNECT_QCOM_RPMH
 	select INTERCONNECT_QCOM_BCM_VOTER
 	help

Signature · 1 line

2.27.0

On Fri 04 Dec 10:50 CST 2020, Arnd Bergmann wrote:

Your patch looks correct to me, so:

Reviewed-by Bjorn Andersson <[email protected]>

But we're going to have to sprinkle a handful of these throughout the tree and we're not a lot of people who "understand" what it does (and at least I keep getting them wrong...)

Perhaps it would be more reasonable to maintain this long term if we drop the possibility of compile testing these drivers independently of rpmh and command db? (I.e. drop the function stubs and rely on RPMH/COMMAND_DB to enable building under COMPILE_TEST)?

And just to make it clear, I think we should merge your patch to fix v5.11; then consider to simplify this past that.