diff mbox

[v10,3/4] ARM64: ACPI: enable ACPI_SPCR_TABLE

Message ID 20160905123617.18775-4-aleksey.makarov@linaro.org
State Accepted
Commit 888125a712986fd0fab99d09f42b307de32d740c
Headers show

Commit Message

Aleksey Makarov Sept. 5, 2016, 12:36 p.m. UTC
SBBR mentions SPCR as a mandatory ACPI table.  So enable it for ARM64

Earlycon should be set up as early as possible.  ACPI boot tables are
mapped in arch/arm64/kernel/acpi.c:acpi_boot_table_init() that
is called from setup_arch() and that's where we parse SPCR.
So it has to be opted-in per-arch.

When ACPI_SPCR_TABLE is defined initialization of DT earlycon is
deferred until the DT/ACPI decision is done.  Initialize DT earlycon
if ACPI is disabled.

Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>

Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>

Tested-by: Christopher Covington <cov@codeaurora.org>

---
 arch/arm64/Kconfig       |  1 +
 arch/arm64/kernel/acpi.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

-- 
2.9.3

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Comments

Hanjun Guo Sept. 8, 2016, 1:35 p.m. UTC | #1
On 2016/9/8 19:16, Will Deacon wrote:
> On Wed, Sep 07, 2016 at 12:30:19PM +0300, Aleksey Makarov wrote:

>>

>> On 09/05/2016 03:36 PM, Aleksey Makarov wrote:

>>> SBBR mentions SPCR as a mandatory ACPI table.  So enable it for ARM64

>>>

>>> Earlycon should be set up as early as possible.  ACPI boot tables are

>>> mapped in arch/arm64/kernel/acpi.c:acpi_boot_table_init() that

>>> is called from setup_arch() and that's where we parse SPCR.

>>> So it has to be opted-in per-arch.

>>>

>>> When ACPI_SPCR_TABLE is defined initialization of DT earlycon is

>>> deferred until the DT/ACPI decision is done.  Initialize DT earlycon

>>> if ACPI is disabled.

>>

>> Hi Will, Catalin,

>>

>> Can you review this patch and consider ACKing it please?

>

> Hanjun, Al, Mark, Graeme -- any comments on this?


We tested this patch on D02, although d02 is 8250 based
uart, but this patch is the core part, which makes sense
to me,

Acked-by: Hanjun Guo <hanjun.guo@linaro.org>


Thanks
Hanjun
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Hanjun Guo Sept. 9, 2016, 9:28 a.m. UTC | #2
On 2016/9/9 0:34, Mark Salter wrote:
> On Thu, 2016-09-08 at 12:16 +0100, Will Deacon wrote:

>> On Wed, Sep 07, 2016 at 12:30:19PM +0300, Aleksey Makarov wrote:

>>>

>>>

>>> On 09/05/2016 03:36 PM, Aleksey Makarov wrote:

>>>>

>>>> SBBR mentions SPCR as a mandatory ACPI table.  So enable it for ARM64

>>>>

>>>> Earlycon should be set up as early as possible.  ACPI boot tables are

>>>> mapped in arch/arm64/kernel/acpi.c:acpi_boot_table_init() that

>>>> is called from setup_arch() and that's where we parse SPCR.

>>>> So it has to be opted-in per-arch.

>>>>

>>>> When ACPI_SPCR_TABLE is defined initialization of DT earlycon is

>>>> deferred until the DT/ACPI decision is done.  Initialize DT earlycon

>>>> if ACPI is disabled.

>>> Hi Will, Catalin,

>>>

>>> Can you review this patch and consider ACKing it please?

>> Hanjun, Al, Mark, Graeme -- any comments on this?

>>

>> Will

>

> I think there is a problem still with systems using 32-bit access to 8250

> UARTs (i.e. Mustang) but that will need a DBG2 table spec change and

> followup patch to resolve.


Hmm, I think you mean we can add patches later with the spec updated,
and this patch works with SBSA pl011 can go for now?

Thanks
Hanjun
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diff mbox

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index bc3f00f..11a2d36 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -4,6 +4,7 @@  config ARM64
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
 	select ACPI_MCFG if ACPI
+	select ACPI_SPCR_TABLE if ACPI
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 3e4f1a4..252a6d9 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -24,6 +24,7 @@ 
 #include <linux/memblock.h>
 #include <linux/of_fdt.h>
 #include <linux/smp.h>
+#include <linux/serial_core.h>
 
 #include <asm/cputype.h>
 #include <asm/cpu_ops.h>
@@ -206,7 +207,7 @@  void __init acpi_boot_table_init(void)
 	if (param_acpi_off ||
 	    (!param_acpi_on && !param_acpi_force &&
 	     of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
-		return;
+		goto done;
 
 	/*
 	 * ACPI is disabled at this point. Enable it in order to parse
@@ -226,6 +227,14 @@  void __init acpi_boot_table_init(void)
 		if (!param_acpi_force)
 			disable_acpi();
 	}
+
+done:
+	if (acpi_disabled) {
+		if (earlycon_init_is_deferred)
+			early_init_dt_scan_chosen_stdout();
+	} else {
+		parse_spcr(earlycon_init_is_deferred);
+	}
 }
 
 #ifdef CONFIG_ACPI_APEI