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Date: Tue, 2 Apr 2013 15:20:05 +0530
From: Sourav Poddar <sourav.poddar@...com>
To: Kevin Hilman <khilman@...aro.org>
CC: Santosh Shilimkar <santosh.shilimkar@...com>,
Felipe Balbi <balbi@...com>, Rajendra nayak <rnayak@...com>,
<tony@...mide.com>, <rmk+kernel@....linux.org.uk>,
<linux-serial@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>
Subject: Re: [PATCH/Resend 2/2] arm: mach-omap2: prevent UART console idle
on suspend while using "no_console_suspend"
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@...com> 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@...com>
>>>> Cc: Felipe Balbi<balbi@...com>
>>>> Cc: Rajendra nayak<rnayak@...com>
>>>> Signed-off-by: Sourav Poddar<sourav.poddar@...com>
>>> 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.
Below is the patch (inlined) which further explains my point. The patch
is "just for the
idea" I am trying to express.
I have used extern variables to exchange information between serial.c
and omap_device.c.
Is there is a better way, we can do this "information exchange" without
using extern variables?
-----
From: Sourav Poddar <sourav.poddar@...com>
Date: Wed, 13 Mar 2013 20:32:36 +0530
Subject: [RFC/PATCH] arm: mach-omap2: prevent UART console idle on
suspend while using "no_console_suspend"
With dt boot on omap5, 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. For non-dt case, this was taken care by
platform data.
Tested on omap5430evm, omap4430sdp.
Signed-off-by: Sourav Poddar <sourav.poddar@...com>
---
The problem is I need to use couple of "extern variables" which
can be used in the omap_device file, after the device is built from dt.
arch/arm/mach-omap2/omap_device.c | 7 ++++++-
arch/arm/mach-omap2/serial.c | 4 +++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/arm/mach-omap2/omap_device.c
b/arch/arm/mach-omap2/omap_device.c
index e065daa..f4ebf9f 100644
--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -96,6 +96,9 @@
#define USE_WAKEUP_LAT 0
#define IGNORE_WAKEUP_LAT 1
+extern u8 no_console_suspend;
+extern char console_uart_name[];
+
static int omap_early_device_register(struct platform_device *pdev);
static struct omap_device_pm_latency omap_default_latency[] = {
@@ -372,7 +375,9 @@ static int omap_device_build_from_dt(struct
platform_device *pdev)
r->name = dev_name(&pdev->dev);
}
- if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
+ if (no_console_suspend && !strcmp(oh->name, console_uart_name))
+ omap_device_disable_idle_on_suspend(pdev);
+ else if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
omap_device_disable_idle_on_suspend(pdev);
pdev->dev.pm_domain = &omap_device_pm_domain;
diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index 037e691..f841ab5 100644
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -63,8 +63,9 @@ struct omap_uart_state {
static LIST_HEAD(uart_list);
static u8 num_uarts;
static u8 console_uart_id = -1;
-static u8 no_console_suspend;
static u8 uart_debug;
+u8 no_console_suspend;
+char console_uart_name[MAX_UART_HWMOD_NAME_LEN];
#define DEFAULT_RXDMA_POLLRATE 1 /* RX DMA polling rate (us) */
#define DEFAULT_RXDMA_BUFSIZE 4096 /* RX DMA buffer size */
@@ -199,6 +200,7 @@ static int __init omap_serial_early_init(void)
"%s%d", OMAP_SERIAL_NAME, uart->num);
if (cmdline_find_option(uart_name)) {
+ strcpy(console_uart_name, oh_name);
console_uart_id = uart->num;
if (console_loglevel >= 10) {
--
1.7.1
~Sourav
>>> Kevin
>>>
>>>> ---
>>>> arch/arm/mach-omap2/omap_device.c | 34
>>>> +++++++++++++++++++++++++++++++++-
>>>> 1 files changed, 33 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/arch/arm/mach-omap2/omap_device.c
>>>> b/arch/arm/mach-omap2/omap_device.c
>>>> index 381be7a..71f5a73 100644
>>>> --- a/arch/arm/mach-omap2/omap_device.c
>>>> +++ b/arch/arm/mach-omap2/omap_device.c
>>>> @@ -35,11 +35,17 @@
>>>> #include<linux/pm_runtime.h>
>>>> #include<linux/of.h>
>>>> #include<linux/notifier.h>
>>>> +#include<linux/platform_data/serial-omap.h>
>>>>
>>>> #include "soc.h"
>>>> #include "omap_device.h"
>>>> #include "omap_hwmod.h"
>>>>
>>>> +#define MAX_UART_HWMOD_NAME_LEN 16
>>>> +
>>>> +static u8 no_console_suspend;
>>>> +static u8 console_uart_num;
>>>> +
>>>> /* Private functions */
>>>>
>>>> static void _add_clkdev(struct omap_device *od, const char
>>>> *clk_alias,
>>>> @@ -108,6 +114,12 @@ static void _add_hwmod_clocks_clkdev(struct
>>>> omap_device *od,
>>>> _add_clkdev(od, oh->opt_clks[i].role, oh->opt_clks[i].clk);
>>>> }
>>>>
>>>> +static char *cmdline_find_option(char *str)
>>>> +{
>>>> + extern char *saved_command_line;
>>>> +
>>>> + return strstr(saved_command_line, str);
>>>> +}
>>>>
>>>> /**
>>>> * omap_device_build_from_dt - build an omap_device with multiple
>>>> hwmods
>>>> @@ -129,6 +141,7 @@ static int omap_device_build_from_dt(struct
>>>> platform_device *pdev)
>>>> struct device_node *node = pdev->dev.of_node;
>>>> const char *oh_name;
>>>> int oh_cnt, i, ret = 0;
>>>> + static u8 console_uart_id;
>>>>
>>>> oh_cnt = of_property_count_strings(node, "ti,hwmods");
>>>> if (!oh_cnt || IS_ERR_VALUE(oh_cnt)) {
>>>> @@ -170,7 +183,12 @@ static int omap_device_build_from_dt(struct
>>>> platform_device *pdev)
>>>> r->name = dev_name(&pdev->dev);
>>>> }
>>>>
>>>> - if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
>>>> + if (no_console_suspend&& !strncmp(oh->name, "uart", 4)) {
>>>> + if (console_uart_num == console_uart_id)
>>>> + omap_device_disable_idle_on_suspend(pdev);
>>>> + else
>>>> + console_uart_id++;
>>>> + } else if (of_get_property(node, "ti,no_idle_on_suspend", NULL))
>>>> omap_device_disable_idle_on_suspend(pdev);
>>>>
>>>> pdev->dev.pm_domain =&omap_device_pm_domain;
>>>> @@ -838,7 +856,21 @@ static struct notifier_block platform_nb = {
>>>>
>>>> static int __init omap_device_init(void)
>>>> {
>>>> + int i;
>>>> + char uart_name[MAX_UART_HWMOD_NAME_LEN];
>>>> +
>>>> bus_register_notifier(&platform_bus_type,&platform_nb);
>>>> +
>>>> + if (cmdline_find_option("no_console_suspend")) {
>>>> + no_console_suspend = true;
>>>> + for (i = 0; i< OMAP_MAX_HSUART_PORTS; i++) {
>>>> + snprintf(uart_name, MAX_UART_HWMOD_NAME_LEN,
>>>> + "%s%d", OMAP_SERIAL_NAME, i);
>>>> + if (cmdline_find_option(uart_name))
>>>> + console_uart_num = i;
>>>> + }
>>>> + }
>>>> +
>>>> return 0;
>>>> }
>>>> omap_core_initcall(omap_device_init);
>>
>
--
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