qemu/sh4-r2d: restore the old sh-sci driver behaviour
PATCH 1/2 qemu/sh4-r2d: restore the old sh-sci driver behaviour
This reverts commit 18e8cf159177100e69d528293f8cf6875c0b1bca (kernel)
The last Qemu kernel update [1] introduced a regresion in sh4 SCIF serial device. Some keyboard presses are very slow to be taken into account, perhaps not even taken into account at all. This would explain why our test infrastructure doesn?t manage to login as root [2][3][4].
git bisect reported a kernel patch from 4.11, increasing RX FIFO trigger defaults value for sh-sci (H)SCIF. The kernel patch itself looks good but the Qemu emulation is not ready to handle this new setting.
From Qemu (2.12.0): target/sh4/README.sh4
"Configuration of the second serial port (SCIF) is supported. FIFO handling infrastructure has been started but is not completed yet."
We can't use the first serial port (ttySC0) because it's the second SH UART that's emulated by Qemu.
In order to be able to test sh4 architecture with newer kernel, revert to the old behaviour.
[1] 03fb00f2175cdb4565e26fcb9b3da1c1059de1bd
[2] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006425
[3] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006427
[4] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006426
--- ...al-sh-sci-increase-RX-FIFO-trigger-defaul.patch | 61 ++++++++++++++++++++++ configs/qemu_sh4_r2d_defconfig | 1 + 2 files changed, 62 insertions(+) create mode 100644 board/qemu/sh4-r2d/patches/linux/0001-Revert-serial-sh-sci-increase-RX-FIFO-trigger-defaul.patch
board/qemu/sh4-r2d/patches/linux/0001-Revert-serial-sh-sci-increase-RX-FIFO-trigger-defaul.patch new file +61 -0
@@ -0,0 +1,61 @@ +From aaaced6d2d6f796ed77e4725ed7ccbedb189c180 Mon Sep 17 00:00:00 2001 +From: Romain Naour <[email protected]> +Date: Fri, 15 Jun 2018 17:43:38 +0200 +Subject: [PATCH] Revert: serial: sh-sci: increase RX FIFO trigger defaults for + (H)SCIF +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +This reverts commit 18e8cf159177100e69d528293f8cf6875c0b1bca (kernel) + +The last Qemu kernel update [1] introduced a regresion in sh4 SCIF +serial device. Some keyboard presses are very slow to be taken into +account, perhaps not even taken into account at all. This would +explain why our test infrastructure doesn?t manage to login as root +[2][3][4]. + +git bisect reported a kernel patch from 4.11, increasing RX FIFO +trigger defaults value for sh-sci (H)SCIF. The kernel patch itself +looks good but the Qemu emulation is not ready to handle this new +setting. + +From Qemu (2.12.0): target/sh4/README.sh4 +"Configuration of the second serial port (SCIF) is supported. FIFO +handling infrastructure has been started but is not completed yet." + +In order to be able to test sh4 architecture with newer kernel, +revert to the old behaviour. + +[1] https://git.buildroot.net/buildroot/commit/?id=03fb00f2175cdb4565e26fcb9b3da1c1059de1bd +[2] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006425 +[3] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006427 +[4] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006426 + +Signed-off-by: Romain Naour <[email protected]> +Cc: Thomas Petazzoni <[email protected]> +--- + drivers/tty/serial/sh-sci.c | 7 ++----- + 1 file changed, 2 insertions(+), 5 deletions(-) + +diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c +index ab757546c6db..138e4dec44fb 100644 +--- a/drivers/tty/serial/sh-sci.c ++++ b/drivers/tty/serial/sh-sci.c +@@ -2793,11 +2793,8 @@ static int sci_init_single(struct platform_device *dev, + sci_port->rx_trigger = 32; + break; + case PORT_SCIF: +- if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) +- /* RX triggering not implemented for this IP */ +- sci_port->rx_trigger = 1; +- else +- sci_port->rx_trigger = 8; ++ /* RX triggering not implemented in Qemu emulation */ ++ sci_port->rx_trigger = 1; + break; + default: + sci_port->rx_trigger = 1; +-- +2.14.4 +
configs/qemu_sh4_r2d_defconfig +1 -0
@@ -3,6 +3,7 @@ BR2_sh=y BR2_sh4=y # System +BR2_GLOBAL_PATCH_DIR="board/qemu/sh4-r2d/patches" BR2_SYSTEM_DHCP="eth0" BR2_TARGET_GENERIC_GETTY_PORT="ttySC1"
Signature · 1 line
2.14.4
PATCH 2/2 qemu/sh4eb-r2d: restore the old sh-sci driver behaviour
As for sh4-r2d (little-endian) restore the old sh-sci driver behaviour for sh4eb-r2d.
Tested with qemu_sh4eb_r2d_defconfig.
--- ...al-sh-sci-increase-RX-FIFO-trigger-defaul.patch | 61 ++++++++++++++++++++++ configs/qemu_sh4eb_r2d_defconfig | 1 + 2 files changed, 62 insertions(+) create mode 100644 board/qemu/sh4eb-r2d/patches/linux/0001-Revert-serial-sh-sci-increase-RX-FIFO-trigger-defaul.patch
board/qemu/sh4eb-r2d/patches/linux/0001-Revert-serial-sh-sci-increase-RX-FIFO-trigger-defaul.patch new file +61 -0
@@ -0,0 +1,61 @@ +From aaaced6d2d6f796ed77e4725ed7ccbedb189c180 Mon Sep 17 00:00:00 2001 +From: Romain Naour <[email protected]> +Date: Fri, 15 Jun 2018 17:43:38 +0200 +Subject: [PATCH] Revert: serial: sh-sci: increase RX FIFO trigger defaults for + (H)SCIF +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +This reverts commit 18e8cf159177100e69d528293f8cf6875c0b1bca (kernel) + +The last Qemu kernel update [1] introduced a regresion in sh4 SCIF +serial device. Some keyboard presses are very slow to be taken into +account, perhaps not even taken into account at all. This would +explain why our test infrastructure doesn?t manage to login as root +[2][3][4]. + +git bisect reported a kernel patch from 4.11, increasing RX FIFO +trigger defaults value for sh-sci (H)SCIF. The kernel patch itself +looks good but the Qemu emulation is not ready to handle this new +setting. + +From Qemu (2.12.0): target/sh4/README.sh4 +"Configuration of the second serial port (SCIF) is supported. FIFO +handling infrastructure has been started but is not completed yet." + +In order to be able to test sh4 architecture with newer kernel, +revert to the old behaviour. + +[1] https://git.buildroot.net/buildroot/commit/?id=03fb00f2175cdb4565e26fcb9b3da1c1059de1bd +[2] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006425 +[3] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006427 +[4] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006426 + +Signed-off-by: Romain Naour <[email protected]> +Cc: Thomas Petazzoni <[email protected]> +--- + drivers/tty/serial/sh-sci.c | 7 ++----- + 1 file changed, 2 insertions(+), 5 deletions(-) + +diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c +index ab757546c6db..138e4dec44fb 100644 +--- a/drivers/tty/serial/sh-sci.c ++++ b/drivers/tty/serial/sh-sci.c +@@ -2793,11 +2793,8 @@ static int sci_init_single(struct platform_device *dev, + sci_port->rx_trigger = 32; + break; + case PORT_SCIF: +- if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) +- /* RX triggering not implemented for this IP */ +- sci_port->rx_trigger = 1; +- else +- sci_port->rx_trigger = 8; ++ /* RX triggering not implemented in Qemu emulation */ ++ sci_port->rx_trigger = 1; + break; + default: + sci_port->rx_trigger = 1; +-- +2.14.4 +
configs/qemu_sh4eb_r2d_defconfig +1 -0
@@ -3,6 +3,7 @@ BR2_sh=y BR2_sh4eb=y # System +BR2_GLOBAL_PATCH_DIR="board/qemu/sh4eb-r2d/patches" BR2_TARGET_GENERIC_GETTY_PORT="ttySC1" # Filesystem
Signature · 1 line
2.14.4
PATCH 1/2 qemu/sh4-r2d: restore the old sh-sci driver behaviour
In reply to Romain NaourHello,
Quoted 28 lines · Romain Naour
This reverts commit
18e8cf159177100e69d528293f8cf6875c0b1bca(kernel)The last Qemu kernel update [1] introduced a regresion in sh4 SCIF serial device. Some keyboard presses are very slow to be taken into account, perhaps not even taken into account at all. This would explain why our test infrastructure doesn?t manage to login as root [2][3][4].
git bisect reported a kernel patch from 4.11, increasing RX FIFO trigger defaults value for sh-sci (H)SCIF. The kernel patch itself looks good but the Qemu emulation is not ready to handle this new setting.
From Qemu (2.12.0): target/sh4/README.sh4
"Configuration of the second serial port (SCIF) is supported. FIFO handling infrastructure has been started but is not completed yet."We can't use the first serial port (ttySC0) because it's the second SH UART that's emulated by Qemu.
In order to be able to test sh4 architecture with newer kernel, revert to the old behaviour.
[1]
03fb00f2175cdb4565e26fcb9b3da1c1059de1bd
[2] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006425
[3] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006427
[4] https://gitlab.com/free-electrons/toolchains-builder/-/jobs/72006426
Quoted 7 lines
Signed-off-by Romain Naour <[email protected]>Cc Thomas Petazzoni <[email protected]>--- ...al-sh-sci-increase-RX-FIFO-trigger-defaul.patch | 61 ++++++++++++++++++++++ configs/qemu_sh4_r2d_defconfig | 1 + 2 files changed, 62 insertions(+) create mode 100644 board/qemu/sh4-r2d/patches/linux/0001-Revert-serial-sh-sci-increase-RX-FIFO-trigger-defaul.patch
Both applied to master. Has the issue been reported to upstream Qemu ?
Thanks!
Thomas
Signature · 3 lines
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com