Re: [PATCH/Resend 2/2] arm: mach-omap2: prevent UART console idleon suspend while using "no_console_suspend"
From: Sourav Poddar
Date: Fri Apr 05 2013 - 03:09:02 EST
Hi Kevin,
On Wednesday 03 April 2013 11:18 PM, Kevin Hilman wrote:
Sourav Poddar<sourav.poddar@xxxxxx> writes:
Hi Kevin,
On Wednesday 20 March 2013 05:36 PM, Sourav Poddar wrote:
Realised the list to whom the patch was send got dropped. Ccing
them all..
On Wednesday 20 March 2013 05:18 PM, Sourav Poddar wrote:
Hi Kevin,
On Tuesday 19 March 2013 12:24 AM, Kevin Hilman wrote:
Sourav Poddar<sourav.poddar@xxxxxx> writes:
With dt boot, uart wakeup after suspend is non functional on
omap4/5 while using
"no_console_suspend" in the bootargs. With "no_console_suspend"
used, od->flags
should be ORed with "OMAP_DEVICE_NO_IDLE_ON_SUSPEND", thereby not
allowing the console
to idle in the suspend path. For non-dt case, this was taken care
by platform data.
Tested on omap5430evm, omap4430sdp.
Cc: Santosh Shilimkar<santosh.shilimkar@xxxxxx>
Cc: Felipe Balbi<balbi@xxxxxx>
Cc: Rajendra nayak<rnayak@xxxxxx>
Signed-off-by: Sourav Poddar<sourav.poddar@xxxxxx>
This patch creates a dependency between omap_device (generic,
device-independent code) and a specific driver (UART.)
If you need to do something like this that's DT boot specific, then
we probably need some late initcall in serial.c to handle this.
It does
not belong in omap_device.
The following function "omap_device_disable_idle_on_suspend(pdev)"
should only
be called once the omap device has been build, which in the case of
device tree is
done in omap_device.c file. Moreover, the above call should be
executed conditionally
and should depend on the following two parameter.
[1] a. Whether "no_console_suspend" is set and
b. the device build is a console uart.
When I look closely into the serial.c file, I realised that
"core_initcall(omap_serial_early_init)" gets called irrespective
of dt/non dt boot and will take care of most of the stuff(checking
whether
"no_console_suspend" is used and which uart is used as a console
uart) which the
$subject patch is proposing.
But the problem is that we need to exchange the parsed information
from serial.c to the omap_device file for the condtional execution of
"omap_device_disable_idle_on_suspend"
In this case,
from "serial.c" we need
1. no_console_suspend = true
2. strcpy(console_name, oh_name), where oh_name corresponds to
the console uart.
then in "omap_device.c" do
if (no_console_suspend&& !strcmp(oh->name, console_name))
omap_device_disable_idle_on_suspend(pdev);
Please correct if I am understanding it incorrectly.
If the above understanding looks good to you, is there a way we can
make this
exchange of information happen between serial.c and omap_device.c file?
Any input on this?
As I explained earlier, that there is a need to parse information in
serial.c and use that in
omap_device.c only after the device is build.
As I explained earlier, any device specific hacks inside omap_device
should be a red flag that something has gone wrong.
How about fixing the UART driver/core to not runtime suspend if
no_console_suspend is given?
Then we can get rid of this no_idle_on_suspend hack all together since
UART is the only remaining user.
Yes, that can be done.
I cooked up an experimental patch, based on your above suggestion. The
patch is
inlined along with the mail. I tested the patch and it resolves
the issue.
Depending on whether no_console_suspend is used or not, we can set a
variable
which can be used as a condition in runtime api's in serial driver.
The information whether "no_console_suspend" is used or not is parsed in
serial.c file, and this need to be communicated to the driver layer.
In my experimental patch below, I have used an extern variable
"force_console_suspend_disable".
Do you see a better way of handling this without using extern?
---------
From: Sourav Poddar <sourav.poddar@xxxxxx>
Date: Wed, 13 Mar 2013 20:32:36 +0530
Subject: [PATCH] arm: mach-omap2: prevent UART console idle on suspend
while using "no_console_suspend"
With dt boot, uart wakeup after suspend is non functional while using
"no_console_suspend" in the bootargs. With "no_console_suspend" used,
od->flags
should be ORed with "OMAP_DEVICE_NO_IDLE_ON_SUSPEND", thereby not
allowing the console
to idle in the suspend path.
Tested on omap5430evm, omap4430sdp.
Signed-off-by: Sourav Poddar <sourav.poddar@xxxxxx>
---
arch/arm/mach-omap2/serial.c | 6 ++++--
drivers/tty/serial/omap-serial.c | 6 +++++-
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index f660156..427c407 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -51,7 +51,7 @@
#define DEFAULT_AUTOSUSPEND_DELAY -1
#define MAX_UART_HWMOD_NAME_LEN 16
-
+int force_console_suspend_disable;
struct omap_uart_state {
int num;
@@ -207,8 +207,10 @@ static int __init omap_serial_early_init(void)
uart_name, uart->num);
}
- if (cmdline_find_option("no_console_suspend"))
+ if (cmdline_find_option("no_console_suspend")) {
+ force_console_suspend_disable = 1;
no_console_suspend = true;
+ }
/*
* omap-uart can be used for earlyprintk logs
diff --git a/drivers/tty/serial/omap-serial.c
b/drivers/tty/serial/omap-serial.c
index 08332f3..395ade8 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -43,6 +43,7 @@
#include <linux/pinctrl/consumer.h>
#include <linux/platform_data/serial-omap.h>
+extern int force_console_suspend_disable;
#define OMAP_MAX_HSUART_PORTS 6
#define UART_BUILD_REVISION(x, y) (((x) << 8) | (y))
@@ -1582,7 +1583,7 @@ static int serial_omap_runtime_suspend(struct
device *dev)
struct uart_omap_port *up = dev_get_drvdata(dev);
struct omap_uart_port_info *pdata = dev->platform_data;
- if (!up)
+ if (!up || force_console_suspend_disable)
return -EINVAL;
if (!pdata)
@@ -1614,6 +1615,9 @@ static int serial_omap_runtime_resume(struct
device *dev)
int loss_cnt = serial_omap_get_context_loss_count(up);
+ if (force_console_suspend_disable)
+ return -EINVAL;
+
if (loss_cnt < 0) {
dev_err(dev, "serial_omap_get_context_loss_count failed : %d\n",
loss_cnt);
--
1.7.1
--
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