Date: Thu, 25 May 2023 17:11:41 GMT From: Mitchell Horne <mhorne@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: cadaabcc720b - main - riscv timer: use stimecmp CSR when available Message-ID: <202305251711.34PHBfTe041686@gitrepo.freebsd.org>
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The branch main has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=cadaabcc720bb20d6d604c4792acb29072d2882d commit cadaabcc720bb20d6d604c4792acb29072d2882d Author: Mitchell Horne <mhorne@FreeBSD.org> AuthorDate: 2023-05-25 17:07:49 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2023-05-25 17:07:49 +0000 riscv timer: use stimecmp CSR when available The Sstc extension defines a new stimecmp CSR, allowing supervisor software to set the timer, rather than just read it. When supported, using this avoids the frequent trips through the SBI every time the CPU's timer expires. Reviewed by: jhb MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D40241 --- sys/riscv/riscv/timer.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/sys/riscv/riscv/timer.c b/sys/riscv/riscv/timer.c index 8f01ef2a720f..d23d88d2c0ec 100644 --- a/sys/riscv/riscv/timer.c +++ b/sys/riscv/riscv/timer.c @@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$"); #include <machine/cpufunc.h> #include <machine/intr.h> +#include <machine/md_var.h> #include <machine/sbi.h> #include <dev/ofw/openfirm.h> @@ -84,6 +85,16 @@ get_timecount(void) return (rdtime()); } +static inline void +set_timecmp(uint64_t timecmp) +{ + + if (has_sstc) + csr_write(stimecmp, timecmp); + else + sbi_set_timer(timecmp); +} + static u_int riscv_timer_tc_get_timecount(struct timecounter *tc __unused) { @@ -107,7 +118,7 @@ riscv_timer_et_start(struct eventtimer *et, sbintime_t first, sbintime_t period) if (first != 0) { counts = ((uint32_t)et->et_frequency * first) >> 32; - sbi_set_timer(get_timecount() + counts); + set_timecmp(get_timecount() + counts); csr_set(sie, SIE_STIE); return (0);
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