Hi Rick, On Tue, Jun 2, 2020 at 5:13 PM Rick Chen <rickche...@gmail.com> wrote: > > Hi Bin > > Bin Meng <bmeng...@gmail.com> 於 2020年6月1日 週一 下午5:06寫道： > > > > Hi Rick, > > > > On Mon, Jun 1, 2020 at 4:14 PM Rick Chen <rickche...@gmail.com> wrote: > > > > > > Hi Bin > > > > > > > From: Bin Meng [mailto:bmeng...@gmail.com] > > > > Sent: Wednesday, May 27, 2020 5:05 PM > > > > To: Rick Jian-Zhi Chen(陳建志); U-Boot Mailing List > > > > Cc: Atish Patra; Bin Meng > > > > Subject: [PATCH 1/2] riscv: sbi: Remove sbi_spec_version > > > > > > > > From: Bin Meng <bin.m...@windriver.com> > > > > > > > > U-Boot defaults to use SBI v0.2. Howerver there is a global variable > > > > sbi_spec_version that stills refers to v0.1. Since it is not used > > > > anywhere, let's remove it. > > > > > > > > Signed-off-by: Bin Meng <bin.m...@windriver.com> > > > > --- > > > > > > > > arch/riscv/include/asm/sbi.h | 2 -- > > > > arch/riscv/lib/sbi.c | 3 --- > > > > 2 files changed, 5 deletions(-) > > > > > > > > diff --git a/arch/riscv/include/asm/sbi.h > > > > b/arch/riscv/include/asm/sbi.h index 453cb5c..08e1ac0 100644 > > > > --- a/arch/riscv/include/asm/sbi.h > > > > +++ b/arch/riscv/include/asm/sbi.h > > > > @@ -77,7 +77,6 @@ enum sbi_ext_rfence_fid { > > > > #define SBI_FID_REMOTE_SFENCE_VMA_ASID > > > > SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID > > > > #endif > > > > > > > > -#define SBI_SPEC_VERSION_DEFAULT 0x1 > > > > #define SBI_SPEC_VERSION_MAJOR_SHIFT 24 > > > > #define SBI_SPEC_VERSION_MAJOR_MASK 0x7f > > > > #define SBI_SPEC_VERSION_MINOR_MASK 0xffffff > > > > @@ -90,7 +89,6 @@ enum sbi_ext_rfence_fid { > > > > #define SBI_ERR_DENIED -4 > > > > #define SBI_ERR_INVALID_ADDRESS -5 > > > > > > > > -extern unsigned long sbi_spec_version; > > > > struct sbiret { > > > > long error; > > > > long value; > > > > diff --git a/arch/riscv/lib/sbi.c b/arch/riscv/lib/sbi.c index > > > > 993597e..f298846 100644 > > > > --- a/arch/riscv/lib/sbi.c > > > > +++ b/arch/riscv/lib/sbi.c > > > > @@ -11,9 +11,6 @@ > > > > #include <asm/encoding.h> > > > > #include <asm/sbi.h> > > > > > > > > -/* default SBI version is 0.1 */ > > > > -unsigned long sbi_spec_version = SBI_SPEC_VERSION_DEFAULT; > > > > > > Why not keep this variable and get version of openSbi automatically, > > > then register v01 or v02 callback function just like sbi_init() of > > > Atish' patch. > > > > I feel this is not needed anyway, because we are using Kconfig option > > to pass the same information. > > U-Boot proper has been configured as SBI_V02 by default currently. > About backward compatible issue, it is not so friendly for users. > They shall select SBI_VERSION configurations correctly in U-Boot > proper and re-compile between different versions of openSbi. > If U-Boot proper can probe openSbi and switch V01 or V02 mode > automatically, users can run smoothly without awareness of SBI > versions. >
OpenSBI v0.7 is not backward compatible with previous version regarding the multicore boot. Dynamically detecting SBI and the SBI implementation version will make U-Boot codes very complicated. In addition to SBI v0.1 vs. v0.2, we need detect whether SBI HSM extension is available and if that's not available, U-Boot has to do the lottery multi-core boot in every stage (SPL and proper). RISC-V is a new architecture and without a lot of legacy burden to carry on, I hope we can do the clean room implementation from the beginning. Regards, Bin
