Commit d1cbfd771ce8 ("ptp_clock: Allow for it to be optional") changed
all PTP-capable Ethernet drivers from `select PTP_1588_CLOCK` to `imply
PTP_1588_CLOCK`, "in order to break the hard dependency between the PTP
clock subsystem and ethernet drivers capable of being clock providers."
As a result it is possible to build PTP-capable Ethernet drivers without
the PTP subsystem by deselecting PTP_1588_CLOCK. Drivers are required to
handle the missing dependency gracefully.
Some PTP-capable Ethernet drivers (e.g., TI_CPSW) factor their PTP code
out into separate drivers (e.g., TI_CPTS_MOD). The above commit also
changed these PTP-specific drivers to `imply PTP_1588_CLOCK`, making it
possible to build them without the PTP subsystem. But as Grygorii
Strashko noted in [1]:
On Wed, Apr 22, 2020 at 02:16:11PM +0300, Grygorii Strashko wrote:
> Another question is that CPTS completely nonfunctional in this case and
> it was never expected that somebody will even try to use/run such
> configuration (except for random build purposes).
In my view, enabling a PTP-specific driver without the PTP subsystem is
a configuration error made possible by the above commit. Kconfig should
not allow users to create a configuration with missing dependencies that
results in "completely nonfunctional" drivers.
I audited all network drivers that call ptp_clock_register() and found
six that look like PTP-specific drivers that are likely nonfunctional
without PTP_1588_CLOCK:
NET_DSA_MV88E6XXX_PTP
NET_DSA_SJA1105_PTP
MACB_USE_HWSTAMP
CAVIUM_PTP
TI_CPTS_MOD
PTP_1588_CLOCK_IXP46X
Note how they all reference PTP or timestamping in their name; this is a
clue that they depend on PTP_1588_CLOCK.
Change these drivers back [2] to `select PTP_1588_CLOCK`. Note that this
requires also selecting POSIX_TIMERS, a transitive dependency of
PTP_1588_CLOCK.
[1]: https://lkml.org/lkml/2020/4/22/1056
[2]: NET_DSA_SJA1105_PTP had never declared any type of dependency on
PTP_1588_CLOCK (`imply` or otherwise); adding it here seems appropriate.
Cc: Arnd Bergmann <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Nicolas Pitre <[email protected]>
Cc: Grygorii Strashko <[email protected]>
Fixes: d1cbfd771ce8 ("ptp_clock: Allow for it to be optional")
Signed-off-by: Clay McClure <[email protected]>
---
drivers/net/dsa/mv88e6xxx/Kconfig | 3 ++-
drivers/net/dsa/sja1105/Kconfig | 2 ++
drivers/net/ethernet/cadence/Kconfig | 3 ++-
drivers/net/ethernet/cavium/Kconfig | 3 ++-
drivers/net/ethernet/ti/Kconfig | 2 +-
drivers/net/ethernet/xscale/Kconfig | 3 ++-
6 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/net/dsa/mv88e6xxx/Kconfig
b/drivers/net/dsa/mv88e6xxx/Kconfig
index 6435020d690d..6e8250599eb1 100644
--- a/drivers/net/dsa/mv88e6xxx/Kconfig
+++ b/drivers/net/dsa/mv88e6xxx/Kconfig
@@ -25,7 +25,8 @@ config NET_DSA_MV88E6XXX_PTP
default n
depends on NET_DSA_MV88E6XXX_GLOBAL2
imply NETWORK_PHY_TIMESTAMPING
- imply PTP_1588_CLOCK
+ select PTP_1588_CLOCK
+ select POSIX_TIMERS
help
Say Y to enable PTP hardware timestamping on Marvell 88E6xxx switch
chips that support it.
diff --git a/drivers/net/dsa/sja1105/Kconfig b/drivers/net/dsa/sja1105/Kconfig
index 0fe1ae173aa1..84349b6c8c44 100644
--- a/drivers/net/dsa/sja1105/Kconfig
+++ b/drivers/net/dsa/sja1105/Kconfig
@@ -20,6 +20,8 @@ tristate "NXP SJA1105 Ethernet switch family support"
config NET_DSA_SJA1105_PTP
bool "Support for the PTP clock on the NXP SJA1105 Ethernet switch"
depends on NET_DSA_SJA1105
+ select PTP_1588_CLOCK
+ select POSIX_TIMERS
help
This enables support for timestamping and PTP clock manipulations in
the SJA1105 DSA driver.
diff --git a/drivers/net/ethernet/cadence/Kconfig
b/drivers/net/ethernet/cadence/Kconfig
index 53b50c24d9c9..bc792c334903 100644
--- a/drivers/net/ethernet/cadence/Kconfig
+++ b/drivers/net/ethernet/cadence/Kconfig
@@ -36,7 +36,8 @@ config MACB_USE_HWSTAMP
bool "Use IEEE 1588 hwstamp"
depends on MACB
default y
- imply PTP_1588_CLOCK
+ select PTP_1588_CLOCK
+ select POSIX_TIMERS
---help---
Enable IEEE 1588 Precision Time Protocol (PTP) support for MACB.
diff --git a/drivers/net/ethernet/cavium/Kconfig
b/drivers/net/ethernet/cavium/Kconfig
index 6a700d34019e..bae58c488792 100644
--- a/drivers/net/ethernet/cavium/Kconfig
+++ b/drivers/net/ethernet/cavium/Kconfig
@@ -54,7 +54,8 @@ config THUNDER_NIC_RGX
config CAVIUM_PTP
tristate "Cavium PTP coprocessor as PTP clock"
depends on 64BIT && PCI
- imply PTP_1588_CLOCK
+ select PTP_1588_CLOCK
+ select POSIX_TIMERS
---help---
This driver adds support for the Precision Time Protocol Clocks and
Timestamping coprocessor (PTP) found on Cavium processors.
diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
index 89cec778cf2d..1177953790c5 100644
--- a/drivers/net/ethernet/ti/Kconfig
+++ b/drivers/net/ethernet/ti/Kconfig
@@ -92,7 +92,7 @@ config TI_CPTS_MOD
depends on TI_CPTS
default y if TI_CPSW=y || TI_KEYSTONE_NETCP=y || TI_CPSW_SWITCHDEV=y
select NET_PTP_CLASSIFY
- imply PTP_1588_CLOCK
+ select PTP_1588_CLOCK
default m
config TI_K3_AM65_CPSW_NUSS
diff --git a/drivers/net/ethernet/xscale/Kconfig
b/drivers/net/ethernet/xscale/Kconfig
index 98aa7b8ddb06..82d4ec3c6398 100644
--- a/drivers/net/ethernet/xscale/Kconfig
+++ b/drivers/net/ethernet/xscale/Kconfig
@@ -30,7 +30,8 @@ config IXP4XX_ETH
config PTP_1588_CLOCK_IXP46X
tristate "Intel IXP46x as PTP clock"
depends on IXP4XX_ETH
- depends on PTP_1588_CLOCK
+ select PTP_1588_CLOCK
+ select POSIX_TIMERS
default y
help
This driver adds support for using the IXP46X as a PTP
--
2.20.1
