Messages in this thread Patch in this message | | | From | Clay McClure <> | Subject | [PATCH] net: Select PTP_1588_CLOCK in PTP-specific drivers | Date | Tue, 28 Apr 2020 02:07:47 -0700 |
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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 <arnd@arndb.de> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Fixes: d1cbfd771ce8 ("ptp_clock: Allow for it to be optional") Signed-off-by: Clay McClure <clay@daemons.net> --- 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
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