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Commitd1cbfd771c("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() but merely `imply PTP_1588_CLOCK` and found five 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 Note how these symbols all reference PTP or timestamping in their name; this is a clue that they depend on PTP_1588_CLOCK. Change them from `imply PTP_1588_CLOCK` [2] to `depends on PTP_1588_CLOCK`. I'm not using `select PTP_1588_CLOCK` here because PTP_1588_CLOCK has its own dependencies, which `select` would not transitively apply. Additionally, remove the `select NET_PTP_CLASSIFY` from CPTS_TI_MOD; PTP_1588_CLOCK already selects that. [1]: https://lore.kernel.org/lkml/c04458ed-29ee-1797-3a11-7f3f560553e6@ti.com/ [2]: NET_DSA_SJA1105_PTP had never declared any type of dependency on PTP_1588_CLOCK (`imply` or otherwise); adding a `depends on PTP_1588_CLOCK` here seems appropriate. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Nicolas Pitre <nico@fluxnic.net> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Fixes:d1cbfd771c("ptp_clock: Allow for it to be optional") Signed-off-by: Clay McClure <clay@daemons.net> Signed-off-by: David S. Miller <davem@davemloft.net>
53 lines
1.4 KiB
Plaintext
53 lines
1.4 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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#
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# Cadence device configuration
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#
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config NET_VENDOR_CADENCE
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bool "Cadence devices"
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depends on HAS_IOMEM
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default y
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---help---
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If you have a network (Ethernet) card belonging to this class, say Y.
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If unsure, say Y.
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Note that the answer to this question doesn't directly affect the
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kernel: saying N will just cause the configurator to skip all the
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remaining Cadence network card questions. If you say Y, you will be
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asked for your specific card in the following questions.
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if NET_VENDOR_CADENCE
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config MACB
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tristate "Cadence MACB/GEM support"
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depends on HAS_DMA && COMMON_CLK
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select PHYLINK
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---help---
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The Cadence MACB ethernet interface is found on many Atmel AT32 and
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AT91 parts. This driver also supports the Cadence GEM (Gigabit
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Ethernet MAC found in some ARM SoC devices). Say Y to include
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support for the MACB/GEM chip.
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To compile this driver as a module, choose M here: the module
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will be macb.
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config MACB_USE_HWSTAMP
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bool "Use IEEE 1588 hwstamp"
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depends on MACB
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depends on PTP_1588_CLOCK
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default y
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---help---
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Enable IEEE 1588 Precision Time Protocol (PTP) support for MACB.
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config MACB_PCI
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tristate "Cadence PCI MACB/GEM support"
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depends on MACB && PCI
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---help---
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This is PCI wrapper for MACB driver.
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To compile this driver as a module, choose M here: the module
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will be called macb_pci.
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endif # NET_VENDOR_CADENCE
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