Hi Ruiyu,
I had seen the other comments and I just needed more time to think about
them :)
Please see my comments below.
On 03/24/2016 03:26 PM, Ni, Ruiyu wrote:
Heyi,
I had 7 comments in previous mail. I guess you may miss the other
comments.
What Timer driver are you using? How many ms does one system tick cost?
If you are using a less-precise timer driver/hardware, one tick may be larger
than
what you expected.
We are using ArmPlatformPkg/Drivers/SP804TimerDxe/SP804TimerDxe.inf as
timer driver.
The frequency of the timer is 200MHz. Timer interrupt period is set to 1ms.
And can you tell me all the UART parameters in your case? What timer
interval
did you get using the equation?
Baud rate = 115200
FIFO depth = 32
Parity = 0
stop = 1
Data size = 8
Polling interval = (1 + 8 + 0 + 1) * 32 / 115200 = 0.00278 (2.78ms)
And please continue to see my opinions for other comments below:
Regards,
Ray
>-----Original Message-----
>From: Heyi Guo [mailto:heyi....@linaro.org]
>Sent: Wednesday, March 23, 2016 5:44 PM
>To: Ni, Ruiyu <ruiyu...@intel.com>; edk2-devel@lists.01.org
>Cc: Tian, Feng <feng.t...@intel.com>; Zeng, Star <star.z...@intel.com>; Kinney,
Michael D <michael.d.kin...@intel.com>
>Subject: Re: [edk2] [PATCH v2 3/3] MdeModulePkg/TerminalDxe: Set polling rate
by serial IO mode
>
>Hi Ruiyu,
>
>Many thanks for your review.
>
>For questions 2#, I tested equation #1 with copy-paste on serial
>terminal, and found it still missing some characters when the FIFO was
>almost full (i.e. near the end of input). I think it is because time
>event is not real-time interrupt; it may be pending for equal or higher TPL.
>
>And a little faster polling rate tested well on real environment.
>
>Please let me know your suggestion.
>
>Regards.
>
>Heyi
>
>On 03/23/2016 04:03 PM, Ni, Ruiyu wrote:
>> Heyi,
>> I have comments in below.
>>
>> Regards,
>> Ray
>>
>>
>>> -----Original Message-----
>>> From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of Heyi
Guo
>>> Sent: Thursday, March 17, 2016 10:37 PM
>>> To: edk2-devel@lists.01.org
>>> Cc: Heyi Guo <heyi....@linaro.org>; Tian, Feng <feng.t...@intel.com>; Zeng, Star
<star.z...@intel.com>
>>> Subject: [edk2] [PATCH v2 3/3] MdeModulePkg/TerminalDxe: Set polling rate
by serial IO mode
>>>
>>> Calculate serial input polling rate according to parameters from
>>> serial IO mode as below, to fix potential input truncation with fixed
>>> polling interval 0.02s.
>>>
>>> Polling interval (100ns) =
>>> FifoDepth * (ParityBits + StopBits + DataBits) * 10,000,000 / BaudRate
>> 1. The above equation (let's call it equation #1) looks good.
>>
Sorry I think I missed the start bit, which should always be 1 bit.
>>> However, as UEFI events will probably delayed by other code of higher
>>> TPL, we use below equation to make polling rate fast enough:
>>>
>>> FifoDepth * DataBits * 10,000,000 * 2 / (BaudRate * 3)
>> 2. Can you tell me why you multiple two in the left of "/" and multiple 3 in
the right?
>> Did you meet any real problem when using the original equation (#1)?
>>
>> I have more comments in below.
>>
>>> Signed-off-by: Heyi Guo <heyi....@linaro.org>
>>> Cc: Feng Tian <feng.t...@intel.com>
>>> Cc: Star Zeng <star.z...@intel.com>
>>> ---
>>> .../Universal/Console/TerminalDxe/Terminal.c | 5 +-
>>> .../Universal/Console/TerminalDxe/Terminal.h | 27 ++++++++-
>>> .../Universal/Console/TerminalDxe/TerminalConIn.c | 68
++++++++++++++++++++++
>>> 3 files changed, 98 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
>>> b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
>>> index 5adaa97..db790f3 100644
>>> --- a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
>>> +++ b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.c
>>> @@ -71,6 +71,7 @@ TERMINAL_DEV mTerminalDevTemplate = {
>>> },
>>> NULL, // TerminalConsoleModeData
>>> 0, // SerialInTimeOut
>>> + DEFAULT_KEYBOARD_TIMER_INTERVAL, // KeyboardTimerInterval
>> 3. Can you remove the default timer interval?
>> We should be able to calculate the timer interval from the default
>> setting (DataBits, StopBits, BaudRate, etc).
>>
See below.
>>> NULL, // RawFifo
>>> NULL, // UnicodeFiFo
>>> @@ -984,10 +985,12 @@ TerminalDriverBindingStart (
>>> );
>>> ASSERT_EFI_ERROR (Status);
>>>
>>> + TerminalDevice->KeyboardTimerInterval = GetKeyboardTimerInterval
(Mode);
>>> +
>>> Status = gBS->SetTimer (
>>> TerminalDevice->TimerEvent,
>>> TimerPeriodic,
>>> - KEYBOARD_TIMER_INTERVAL
>>> + TerminalDevice->KeyboardTimerInterval
>>> );
>>> ASSERT_EFI_ERROR (Status);
>>>
>>> diff --git a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
>>> b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
>>> index 269d2ae..58d5664 100644
>>> --- a/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
>>> +++ b/MdeModulePkg/Universal/Console/TerminalDxe/Terminal.h
>>> @@ -68,7 +68,7 @@ typedef struct {
>>> UINTN Rows;
>>> } TERMINAL_CONSOLE_MODE_DATA;
>>>
>>> -#define KEYBOARD_TIMER_INTERVAL 200000 // 0.02s
>>> +#define DEFAULT_KEYBOARD_TIMER_INTERVAL 200000 // 0.02s
>>
>> 4. Same question as #3.
>>
>>> #define TERMINAL_DEV_SIGNATURE SIGNATURE_32 ('t', 'm', 'n', 'l')
>>>
>>> @@ -91,6 +91,7 @@ typedef struct {
>>> EFI_SIMPLE_TEXT_OUTPUT_MODE SimpleTextOutputMode;
>>> TERMINAL_CONSOLE_MODE_DATA *TerminalConsoleModeData;
>>> UINTN SerialInTimeOut;
>>> + UINT64 KeyboardTimerInterval;
>>> RAW_DATA_FIFO *RawFiFo;
>>> UNICODE_FIFO *UnicodeFiFo;
>>> EFI_KEY_FIFO *EfiKeyFiFo;
>>> @@ -1358,4 +1359,28 @@ TerminalConInTimerHandler (
>>> IN EFI_EVENT Event,
>>> IN VOID *Context
>>> );
>>> +
>>> +/**
>>> + Calculate input polling timer interval by serial IO mode.
>>> +
>>> + @param Mode Pointer to serial IO mode.
>>> +
>>> + @retval The required polling timer interval in 100ns.
>>> +
>>> +**/
>>> +UINT64
>>> +GetKeyboardTimerInterval (
>>> + IN EFI_SERIAL_IO_MODE *Mode
>>> + );
>>> +
>>> +/**
>>> + Update period of polling timer event.
>>> +
>>> + @param TerminalDevice The terminal device to update.
>>> +**/
>>> +VOID
>>> +UpdatePollingRate (
>>> + IN TERMINAL_DEV *TerminalDevice
>>> + );
>>> +
>>> #endif
>>> diff --git a/MdeModulePkg/Universal/Console/TerminalDxe/TerminalConIn.c
>>> b/MdeModulePkg/Universal/Console/TerminalDxe/TerminalConIn.c
>>> index 2215df6..22349a0 100644
>>> --- a/MdeModulePkg/Universal/Console/TerminalDxe/TerminalConIn.c
>>> +++ b/MdeModulePkg/Universal/Console/TerminalDxe/TerminalConIn.c
>>> @@ -502,6 +502,71 @@ TerminalConInWaitForKey (
>>> }
>>>
>>> /**
>>> + Calculate input polling timer interval by serial IO mode.
>>> +
>>> + @param Mode Pointer to serial IO mode.
>>> +
>>> + @retval The required polling timer interval in 100ns.
>>> +
>>> +**/
>>> +UINT64
>>> +GetKeyboardTimerInterval (
>>> + IN EFI_SERIAL_IO_MODE *Mode
>>> + )
>>> +{
>>> + UINT32 FifoDepth;
>>> +
>>> + if (Mode->BaudRate == 0) {
>>> + return DEFAULT_KEYBOARD_TIMER_INTERVAL;
>>> + }
>> 5. Now I understand you need the default timer interval for the default
setting.
>> Because UEFI spec says when the baud rate has the value of 0 to indicate the
device
>> runs at the device's *designed speed*.
>> But I still think you can calculate the timer interval assuming the baudrate
is 115200.
>> Because if using 115200 the timer interval is about 0.001s which is still
shorter than 0.02s.
>>
Sounds good for me.
>>> +
>>> + FifoDepth = Mode->ReceiveFifoDepth;
>>> + // Fix incorrect FIFO depth
>>> + if (FifoDepth == 0) {
>>> + FifoDepth = 1;
>>> + }
>>> +
>>> + // We ignore stop bits and parity bit, and reduce the interval by 1/3,
>>> + // to make polling rate fast enough to avoid serial input truncation.
>>> + return DivU64x64Remainder (
>>> + FifoDepth * Mode->DataBits * 10000000 * 2,
>>> + Mode->BaudRate * 3,
>>> + NULL
>>> + );
>>> +}
>> 6. Same question. Can you use the original equation #1?
>>
>>> +
>>> +
>>> +/**
>>> + Update period of polling timer event.
>>> +
>>> + @param TerminalDevice The terminal device to update.
>>> +**/
>>> +VOID
>>> +UpdatePollingRate (
>>> + IN TERMINAL_DEV *TerminalDevice
>>> + )
>>> +{
>>> + UINT64 NewInterval;
>>> + EFI_STATUS Status;
>>> +
>>> + NewInterval = GetKeyboardTimerInterval (TerminalDevice->SerialIo->Mode);
>>> +
>>> + if (TerminalDevice->KeyboardTimerInterval == NewInterval) {
>>> + return;
>>> + }
>>> +
>>> + Status = gBS->SetTimer (
>>> + TerminalDevice->TimerEvent,
>>> + TimerPeriodic,
>>> + NewInterval
>>> + );
>>> + ASSERT_EFI_ERROR (Status);
>>> +
>>> + TerminalDevice->KeyboardTimerInterval = NewInterval;
>>> +}
>>> +
>>> +
>>> +/**
>>> Timer handler to poll the key from serial.
>>>
>>> @param Event Indicates the event that invoke this
function.
>>> @@ -560,6 +625,9 @@ TerminalConInTimerHandler (
>>> TerminalDevice->SerialInTimeOut = SerialInTimeOut;
>>> }
>>> }
>>> +
>>> + UpdatePollingRate (TerminalDevice);
>> 7. All the parameters (baudrate, databits, stopbits,etc) are stored in the
UART device path.
>> Any change to these parameters triggers the UART device path reinstallation,
ultimately
>> triggers the Terminal driver's restart.
>> So the polling rate doesn't need to update here.
>>
How about FIFO depth change?
Thanks for your review :)
Heyi
>>> +
>>> //
>>> // Check whether serial buffer is empty.
>>> // Skip the key transfer loop only if the SerialIo protocol instance
>>> --
>>> 2.7.0
>>>
>>> _______________________________________________
>>> edk2-devel mailing list
>>> edk2-devel@lists.01.org
>>> https://lists.01.org/mailman/listinfo/edk2-devel
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