From: "Andrei Warkentin" <andrei.warkentin@intel.com>
To: Gerd Hoffmann <kraxel@redhat.com>,
"devel@edk2.groups.io" <devel@edk2.groups.io>
Cc: Daniel Schaefer <git@danielschaefer.me>,
Sunil V L <sunilvl@ventanamicro.com>
Subject: Re: [edk2-devel] [edk2 2/2] MdePkg: add BaseSerialPortLibRiscVSbi
Date: Wed, 1 Mar 2023 08:50:38 +0000 [thread overview]
Message-ID: <PH8PR11MB68563E2FBD725A773B6ABF6583AD9@PH8PR11MB6856.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20230301081332.lzb5v7enjfillnfb@sirius.home.kraxel.org>
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The library caller could call Poll() first, then call Read(), and the expectation is the char won't be lost. SBI doesn't have a poll call itself, so best you could do is read and stash. So you have to stash it globally. And read must use the stashed char, if it exists, before requesting more data from SBI. At that point, reading is easy to treat as continued polling - just to keep the code simple.
A
________________________________
От: Gerd Hoffmann <kraxel@redhat.com>
Отправлено: Wednesday, March 1, 2023 2:13:32 AM
Кому: devel@edk2.groups.io <devel@edk2.groups.io>; Warkentin, Andrei <andrei.warkentin@intel.com>
Копия: Daniel Schaefer <git@danielschaefer.me>; Sunil V L <sunilvl@ventanamicro.com>
Тема: Re: [edk2-devel] [edk2 2/2] MdePkg: add BaseSerialPortLibRiscVSbi
Hi,
> + while ((Index < NumberOfBytes) && SerialPortPoll ()) {
> + Buffer[Index++] = (UINT8)mLastGetChar;
> + mLastGetChar = -1;
> + }
Why do you use a global variable to pass the character? SerialPortPoll
could just return it directly ...
take care,
Gerd
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next prev parent reply other threads:[~2023-03-01 8:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-01 7:43 [edk2 0/2] RISC-V SBI-backed SerialLib Andrei Warkentin
2023-03-01 7:43 ` [edk2 1/2] MdePkg: BaseRiscVSbiLib: make more useful to consumers Andrei Warkentin
2023-03-01 7:43 ` [edk2 2/2] MdePkg: add BaseSerialPortLibRiscVSbi Andrei Warkentin
2023-03-01 8:13 ` [edk2-devel] " Gerd Hoffmann
2023-03-01 8:50 ` Andrei Warkentin [this message]
2023-03-01 9:07 ` Gerd Hoffmann
2023-03-01 16:55 ` Michael D Kinney
2023-03-01 17:26 ` Andrei Warkentin
2023-03-01 17:51 ` Michael D Kinney
2023-03-01 17:56 ` Andrei Warkentin
2023-03-02 10:34 ` Sunil V L
2023-03-02 13:32 ` Andrei Warkentin
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