ARM: shmobile: Check r8a7791 MD21 at SMP boot
Magnus Damm
maintainerPATCH 1/1 ARM: shmobile: Check r8a7791 MD21 at SMP boot
From: Magnus Damm <[email protected]>
On r8a7791 the hardware boot mode bit MD21 indicates if hardware debug mode is enabled or not. In case hardware debug mode is enabled print a warning and refrain from booting secondary CPU cores.
Without this patch Koelsch with SW8-4 set to OFF will hang at SMP boot.
---
This is a reworked version of the APMU patch previously posted as [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Written against renesas-devel-v3.14-rc4-20140226
arch/arm/mach-shmobile/smp-r8a7791.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
arch/arm/mach-shmobile/smp-r8a7791.c +14 -1
@@ -20,6 +20,7 @@#include <asm/smp_plat.h> #include <mach/common.h> #include <mach/r8a7791.h> +#include <mach/rcar-gen2.h> #define RST 0xe6160000#define CA15BAR 0x0020
@@ -51,9 +52,21 @@ static void __init r8a7791_smp_prepare_ciounmap (p); } +static int r8a7791_smp_boot_secondary (unsigned int cpu, +struct task_struct *idle) +{ +/* Error out when hardware debug mode is enabled */ +if (rcar_gen2_read_mode_pins () &BIT (21 )) { +pr_warn ("Unable to boot CPU%u when MD21 is set\n" , cpu); +return -ENOTSUPP ; + } + +return shmobile_smp_apmu_boot_secondary (cpu, idle); +} +struct smp_operations r8a7791_smp_ops__initdata = { .smp_prepare_cpus = r8a7791_smp_prepare_cpus, - .smp_boot_secondary = shmobile_smp_apmu_boot_secondary, + .smp_boot_secondary = r8a7791_smp_boot_secondary, #ifdef CONFIG_HOTPLUG_CPU .cpu_disable = shmobile_smp_cpu_disable, .cpu_die = shmobile_smp_apmu_cpu_die,
PATCH 1/1 ARM: shmobile: Check r8a7791 MD21 at SMP boot
Hi Magnus,
Quoted 7 lines · Magnus Damm
On r8a7791 the hardware boot mode bit MD21 indicates if hardware debug mode is enabled or not. In case hardware debug mode is enabled print a warning and refrain from booting secondary CPU cores.
Without this patch Koelsch with SW8-4 set to OFF will hang at SMP boot.
Signed-off-by Magnus Damm <[email protected]>
On Koelsch:
Quoted 2 lines
This is a reworked version of the APMU patch previously posted as [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Your previous version also affected r8a7790/Lager.
Isn't this check no longer needed there? According to the Lager manual, MD21 also enables hardware debug mode, and is also controlled by SW8-4. Of course the CPU may behave differently, as the CPU cores are different.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
Magnus Damm
maintainerPATCH 1/1 ARM: shmobile: Check r8a7791 MD21 at SMP boot
Hi Geert,
Quoted 7 lines · Geert Uytterhoeven
Hi Magnus,
Quoted 4 lines · Magnus Damm
On r8a7791 the hardware boot mode bit MD21 indicates if hardware debug mode is enabled or not. In case hardware debug mode is enabled print a warning and refrain from booting secondary CPU cores.
Quoted 7 lines
Quoted 3 lines
Without this patch Koelsch with SW8-4 set to OFF will hang at SMP boot.
Signed-off-by Magnus Damm <[email protected]>On Koelsch:
Tested-by Geert Uytterhoeven <[email protected]>
Thanks.
Quoted 8 lines
Quoted 2 lines
This is a reworked version of the APMU patch previously posted as [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Your previous version also affected r8a7790/Lager.
Isn't this check no longer needed there? According to the Lager manual, MD21 also enables hardware debug mode, and is also controlled by SW8-4. Of course the CPU may behave differently, as the CPU cores are different.
Yes, you are correct that the previous version of the patch also affected Lager. And that both r8a7790 and r8a7791 mention the MD21 bit together with JTAG debugging.
I recently used the patch on Lager and I discovered that I apparently had been running with MD21 on my Lager since forever, and surprisingly it worked regardless. Since there is no documentation on r8a7790 or r8a7791 I simply decided to handle them separately and only enable where it is needed.
I've also been told that it is possible to allow SMP operation together with JTAG, apparently some magic with RST is needed. It seems that the power domains are treated differently depending on the MD21 setting. Not sure if this applies to both r8a7790 and r8a7791, but if we end up with similar fixes we can consolidate. Until then I think dealing with them one by one makes sense.
Cheers,
/ magnus
PATCH 1/1 ARM: shmobile: Check r8a7791 MD21 at SMP boot
Hi Magnus,
Quoted 13 lines · Magnus Damm
Quoted 8 lines
Quoted 2 lines
This is a reworked version of the APMU patch previously posted as [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Your previous version also affected r8a7790/Lager.
Isn't this check no longer needed there? According to the Lager manual, MD21 also enables hardware debug mode, and is also controlled by SW8-4. Of course the CPU may behave differently, as the CPU cores are different.Yes, you are correct that the previous version of the patch also affected Lager. And that both r8a7790 and r8a7791 mention the MD21 bit together with JTAG debugging.
Quoted 5 lines
I recently used the patch on Lager and I discovered that I apparently had been running with MD21 on my Lager since forever, and surprisingly it worked regardless. Since there is no documentation on r8a7790 or r8a7791 I simply decided to handle them separately and only enable where it is needed.
You could have been lucky?
On Koelsch, I only had failures after Real Cold Boot, i.e. on boot up in the morning. And not always, so there could be a timing issue involved.
Quoted 6 lines
I've also been told that it is possible to allow SMP operation together with JTAG, apparently some magic with RST is needed. It seems that the power domains are treated differently depending on the MD21 setting. Not sure if this applies to both r8a7790 and r8a7791, but if we end up with similar fixes we can consolidate. Until then I think dealing with them one by one makes sense.
Furthermore, I haven't seen any SPI timeouts after I disabled MD21 (holding wood, and rabbit legs ;-). So the SMP memory (in)coherency I saw there could have been caused by a wobbly SMP setup.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
PATCH 1/1 ARM: shmobile: Check r8a7791 MD21 at SMP boot
Quoted 34 lines · Geert Uytterhoeven
Hi Magnus,
Quoted 13 lines · Magnus Damm
Quoted 8 lines
Quoted 2 lines
This is a reworked version of the APMU patch previously posted as [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Your previous version also affected r8a7790/Lager.
Isn't this check no longer needed there? According to the Lager manual, MD21 also enables hardware debug mode, and is also controlled by SW8-4. Of course the CPU may behave differently, as the CPU cores are different.Yes, you are correct that the previous version of the patch also affected Lager. And that both r8a7790 and r8a7791 mention the MD21 bit together with JTAG debugging.
Quoted 5 lines
I recently used the patch on Lager and I discovered that I apparently had been running with MD21 on my Lager since forever, and surprisingly it worked regardless. Since there is no documentation on r8a7790 or r8a7791 I simply decided to handle them separately and only enable where it is needed.
You could have been lucky?
On Koelsch, I only had failures after Real Cold Boot, i.e. on boot up in the morning. And not always, so there could be a timing issue involved.
Quoted 6 lines
I've also been told that it is possible to allow SMP operation together with JTAG, apparently some magic with RST is needed. It seems that the power domains are treated differently depending on the MD21 setting. Not sure if this applies to both r8a7790 and r8a7791, but if we end up with similar fixes we can consolidate. Until then I think dealing with them one by one makes sense.
Quoted 3 lines
Furthermore, I haven't seen any SPI timeouts after I disabled MD21 (holding wood, and rabbit legs ;-). So the SMP memory (in)coherency I saw there could have been caused by a wobbly SMP setup.
Hi Magnus,
I am a little confused about the status of this patch? Would you like me to queue it up?
Magnus Damm
maintainerPATCH 1/1 ARM: shmobile: Check r8a7791 MD21 at SMP boot
Hi Simon,
Quoted 35 lines · Simon Horman
Quoted 34 lines · Geert Uytterhoeven
Hi Magnus,
Quoted 13 lines · Magnus Damm
Quoted 8 lines
Quoted 2 lines
This is a reworked version of the APMU patch previously posted as [PATCH] ARM: shmobile: Check MD21 at SMP boot in case of APMU
Your previous version also affected r8a7790/Lager.
Isn't this check no longer needed there? According to the Lager manual, MD21 also enables hardware debug mode, and is also controlled by SW8-4. Of course the CPU may behave differently, as the CPU cores are different.Yes, you are correct that the previous version of the patch also affected Lager. And that both r8a7790 and r8a7791 mention the MD21 bit together with JTAG debugging.
Quoted 5 lines
I recently used the patch on Lager and I discovered that I apparently had been running with MD21 on my Lager since forever, and surprisingly it worked regardless. Since there is no documentation on r8a7790 or r8a7791 I simply decided to handle them separately and only enable where it is needed.
You could have been lucky?
On Koelsch, I only had failures after Real Cold Boot, i.e. on boot up in the morning. And not always, so there could be a timing issue involved.
Quoted 6 lines
I've also been told that it is possible to allow SMP operation together with JTAG, apparently some magic with RST is needed. It seems that the power domains are treated differently depending on the MD21 setting. Not sure if this applies to both r8a7790 and r8a7791, but if we end up with similar fixes we can consolidate. Until then I think dealing with them one by one makes sense.
Quoted 8 lines
Quoted 3 lines
Furthermore, I haven't seen any SPI timeouts after I disabled MD21 (holding wood, and rabbit legs ;-). So the SMP memory (in)coherency I saw there could have been caused by a wobbly SMP setup.
Hi Magnus,
I am a little confused about the status of this patch? Would you like me to queue it up?
Yes, please!
/ magnus