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linux/drivers/clocksource/timer-rtl-otto.c

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clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Work around dying timers The OpenWrt distribution has switched from kernel longterm 6.6 to 6.12. Reports show that devices with the Realtek Otto switch platform die during operation and are rebooted by the watchdog. Sorting out other possible reasons the Otto timer is to blame. The platform currently consists of 4 targets with different hardware revisions. It is not 100% clear which devices and revisions are affected. Analysis shows: A more aggressive sched/deadline handling leads to more timer starts with small intervals. This increases the bug chances. See https://marc.info/?l=linux-kernel&m=175276556023276&w=2 Focusing on the real issue a hardware limitation on some devices was found. There is a minimal chance that a timer ends without firing an interrupt if it is reprogrammed within the 5us before its expiration time. Work around this issue by introducing a bounce() function. It restarts the timer directly before the normal restart functions as follows: - Stop timer - Restart timer with a slow frequency. - Target time will be >5us - The subsequent normal restart is outside the critical window Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-2-markus.stockhausen@gmx.de
2025-08-04 04:03:25 -04:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Simplify documentation While the main SoC PLL is responsible for the lexra bus frequency it has no implications on the the timer divisior. Update the comments accordingly. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20250804080328.2609287-5-markus.stockhausen@gmx.de
2025-08-04 04:03:28 -04:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/rtl-otto: Change driver to use __raw reads and writes As it stands, the driver uses ioread32 and iowrite32 for register access and it works fine. However this stops working when the SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and iowrite32 to be in native endian (that is big endian for currently supported SoCs). RTL9607C is a big endian MIPS SoC that has identical timer as the already supported chips but needs to have SWAP_IO_SPACE to have a functioning little endian USB host. Fix this by replacing all instances of ioread32 and iowrite32 with __raw_readl and __raw_writel variants. Since they essentially do the same register access, this shouldn't affect anything on other machines. Signed-off-by: Rustam Adilov <adilov@disroot.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://patch.msgid.link/20260725175510.77240-1-adilov@disroot.org
2026-07-25 22:55:10 +05:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Work around dying timers The OpenWrt distribution has switched from kernel longterm 6.6 to 6.12. Reports show that devices with the Realtek Otto switch platform die during operation and are rebooted by the watchdog. Sorting out other possible reasons the Otto timer is to blame. The platform currently consists of 4 targets with different hardware revisions. It is not 100% clear which devices and revisions are affected. Analysis shows: A more aggressive sched/deadline handling leads to more timer starts with small intervals. This increases the bug chances. See https://marc.info/?l=linux-kernel&m=175276556023276&w=2 Focusing on the real issue a hardware limitation on some devices was found. There is a minimal chance that a timer ends without firing an interrupt if it is reprogrammed within the 5us before its expiration time. Work around this issue by introducing a bounce() function. It restarts the timer directly before the normal restart functions as follows: - Stop timer - Restart timer with a slow frequency. - Target time will be >5us - The subsequent normal restart is outside the critical window Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-2-markus.stockhausen@gmx.de
2025-08-04 04:03:25 -04:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Work around dying timers The OpenWrt distribution has switched from kernel longterm 6.6 to 6.12. Reports show that devices with the Realtek Otto switch platform die during operation and are rebooted by the watchdog. Sorting out other possible reasons the Otto timer is to blame. The platform currently consists of 4 targets with different hardware revisions. It is not 100% clear which devices and revisions are affected. Analysis shows: A more aggressive sched/deadline handling leads to more timer starts with small intervals. This increases the bug chances. See https://marc.info/?l=linux-kernel&m=175276556023276&w=2 Focusing on the real issue a hardware limitation on some devices was found. There is a minimal chance that a timer ends without firing an interrupt if it is reprogrammed within the 5us before its expiration time. Work around this issue by introducing a bounce() function. It restarts the timer directly before the normal restart functions as follows: - Stop timer - Restart timer with a slow frequency. - Target time will be >5us - The subsequent normal restart is outside the critical window Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-2-markus.stockhausen@gmx.de
2025-08-04 04:03:25 -04:00
clocksource/drivers/timer-rtl-otto: Do not interfere with interrupts During normal operation the timers are reprogrammed including an interrupt acknowledgement. This has no effect as the whole timer is setup from scratch afterwards. Especially in an interrupt this has already been done by rttm_timer_interrupt(). Change the behaviour as follows: - Use rttm_disable_timer() during reprogramming - Keep rttm_stop_timer() for all other use cases. Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-4-markus.stockhausen@gmx.de
2025-08-04 04:03:27 -04:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Work around dying timers The OpenWrt distribution has switched from kernel longterm 6.6 to 6.12. Reports show that devices with the Realtek Otto switch platform die during operation and are rebooted by the watchdog. Sorting out other possible reasons the Otto timer is to blame. The platform currently consists of 4 targets with different hardware revisions. It is not 100% clear which devices and revisions are affected. Analysis shows: A more aggressive sched/deadline handling leads to more timer starts with small intervals. This increases the bug chances. See https://marc.info/?l=linux-kernel&m=175276556023276&w=2 Focusing on the real issue a hardware limitation on some devices was found. There is a minimal chance that a timer ends without firing an interrupt if it is reprogrammed within the 5us before its expiration time. Work around this issue by introducing a bounce() function. It restarts the timer directly before the normal restart functions as follows: - Stop timer - Restart timer with a slow frequency. - Target time will be >5us - The subsequent normal restart is outside the critical window Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-2-markus.stockhausen@gmx.de
2025-08-04 04:03:25 -04:00
clocksource/drivers/timer-rtl-otto: Do not interfere with interrupts During normal operation the timers are reprogrammed including an interrupt acknowledgement. This has no effect as the whole timer is setup from scratch afterwards. Especially in an interrupt this has already been done by rttm_timer_interrupt(). Change the behaviour as follows: - Use rttm_disable_timer() during reprogramming - Keep rttm_stop_timer() for all other use cases. Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-4-markus.stockhausen@gmx.de
2025-08-04 04:03:27 -04:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Work around dying timers The OpenWrt distribution has switched from kernel longterm 6.6 to 6.12. Reports show that devices with the Realtek Otto switch platform die during operation and are rebooted by the watchdog. Sorting out other possible reasons the Otto timer is to blame. The platform currently consists of 4 targets with different hardware revisions. It is not 100% clear which devices and revisions are affected. Analysis shows: A more aggressive sched/deadline handling leads to more timer starts with small intervals. This increases the bug chances. See https://marc.info/?l=linux-kernel&m=175276556023276&w=2 Focusing on the real issue a hardware limitation on some devices was found. There is a minimal chance that a timer ends without firing an interrupt if it is reprogrammed within the 5us before its expiration time. Work around this issue by introducing a bounce() function. It restarts the timer directly before the normal restart functions as follows: - Stop timer - Restart timer with a slow frequency. - Target time will be >5us - The subsequent normal restart is outside the critical window Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-2-markus.stockhausen@gmx.de
2025-08-04 04:03:25 -04:00
clocksource/drivers/timer-rtl-otto: Do not interfere with interrupts During normal operation the timers are reprogrammed including an interrupt acknowledgement. This has no effect as the whole timer is setup from scratch afterwards. Especially in an interrupt this has already been done by rttm_timer_interrupt(). Change the behaviour as follows: - Use rttm_disable_timer() during reprogramming - Keep rttm_stop_timer() for all other use cases. Downstream has already tested and confirmed a patch. See https://github.com/openwrt/openwrt/pull/19468 https://forum.openwrt.org/t/support-for-rtl838x-based-managed-switches/57875/3788 Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Tested-by: Stephen Howell <howels@allthatwemight.be> Tested-by: Bjørn Mork <bjorn@mork.no> Link: https://lore.kernel.org/r/20250804080328.2609287-4-markus.stockhausen@gmx.de
2025-08-04 04:03:27 -04:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00
clocksource/drivers/timer-rtl-otto: Make rttm_cs variable static File-scope 'rttm_cs' is not used outside of this unit, so make it static to silence sparse warning: timer-rtl-otto.c:228:16: warning: symbol 'rttm_cs' was not declared. Should it be static? Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org> Link: https://patch.msgid.link/20260216110306.159822-2-krzysztof.kozlowski@oss.qualcomm.com
2026-02-16 12:03:07 +01:00
clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> Signed-off-by: Sander Vanheule <sander@svanheule.net> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2024-07-10 16:35:21 +12:00