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[83.59.162.106]) by smtp.gmail.com with ESMTPSA id 205sm2705471wme.38.2020.10.10.13.43.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 10 Oct 2020 13:43:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=BslzpywZz3mbJWKAE8qW6xsdeqX9i4THsloWKfBnQUU=; b=EmbwK9TZknnui4PQOgQRnw5vZMBRygMvlsFVsqpCk1KVMxkXBOJYLRE/UA9YqiHwkw E18r+J7lGucOVtL9uT8fUvHNd1M9U/7QAHSfsMBQ/Z2wcUaS9yHEazHEDBh3i/9aS9Nq pz+nGobjsQWDzwKx64m9OhPiwPK+WOyFuyYakVlYKLm1C/7atYj3pqdIQxLW0CQD+CD1 BiVSSFzrYen0FLzhmozgDQBjGNtSLS7uug78jPwMU+9yNdfe7DmIyloBKErJEdrv30wD wF3I6sAtMKhjjUJpfEoywFXGp6xWPSNYWQaR9dMd4WTpEddDzTtR5TgwdrA4LGu6Nd0R HoXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=BslzpywZz3mbJWKAE8qW6xsdeqX9i4THsloWKfBnQUU=; b=Wrsx0hdNbEaaZF7nEy0U3wU5Dn8m58bfKjPXHafSTgNiSq9K2DnYABPOHavYJIime+ FOKjyIfZ2QJTBpO2SBT+cdiQCZC0HRxedH3vUaLeE1FzSHy4tTiyf/RGQTnJxOPZzvMn l7uYWzENFBuHftEtzE6PguRrqr5hGeTg+4wNMZbTNR679jAa8yBeeI+50SbOTSHOKAvT ue17LTbZiCe2lgccD8lXUIRjm6J34M57FihHNBac5cdfM8Rx95vlB/wXf6wIkCGw0NKf 3DD2VMQeRdEi8VZ8W3sO6a6RmQ3RXV87s6fQMVIN+1/DZsMhLk8fz1P+5jQHokZ0I6P0 DfFQ== X-Gm-Message-State: AOAM533u9UF+BYVDiXKSxcdf8NODYLaFwM+bzmdzuHz6+HfBW6Ef+Bok CV/dg//v8ztbdOgbC1ZGwjE= X-Google-Smtp-Source: ABdhPJzxcI4inkXz91djExO+yIevY0gkOJ1BWFgYfjPAUqtmvqSef6nnp3lj6HJccHSQ2RAmVy5Puw== X-Received: by 2002:adf:e6c4:: with SMTP id y4mr21979890wrm.423.1602362611760; Sat, 10 Oct 2020 13:43:31 -0700 (PDT) Sender: =?UTF-8?Q?Philippe_Mathieu=2DDaud=C3=A9?= From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Huacai Chen , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Damien Hedde , Paul Burton , Luc Michel , Aleksandar Rikalo , Huacai Chen , Richard Henderson , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Eduardo Habkost , =?UTF-8?q?Herv=C3=A9=20Poussineau?= , Paolo Bonzini , Aurelien Jarno , Jiaxun Yang Subject: [PATCH v3 07/20] target/mips/cp0_timer: Document TIMER_PERIOD origin Date: Sat, 10 Oct 2020 22:43:06 +0200 Message-Id: <20201010204319.3119239-8-f4bug@amsat.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201010204319.3119239-1-f4bug@amsat.org> References: <20201010204319.3119239-1-f4bug@amsat.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @gmail.com) TIMER_PERIOD value of '10 ns' can be explained looking at commit 6af0bf9c7c3doc, where the CPU frequency is 200 MHz and CP0 default count rate is half the frequency of the CPU. Document that. Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- target/mips/cp0_timer.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/target/mips/cp0_timer.c b/target/mips/cp0_timer.c index 5194c967ae3..6fec5fe0ff7 100644 --- a/target/mips/cp0_timer.c +++ b/target/mips/cp0_timer.c @@ -27,7 +27,17 @@ #include "sysemu/kvm.h" #include "internal.h" =20 -#define TIMER_PERIOD 10 /* 10 ns period for 100 Mhz frequency */ +/* + * Since commit 6af0bf9c7c3 this model assumes a CPU clocked at 200MHz + * and a CP0 timer running at half the clock of the CPU (cp0_count_rate = =3D 2). + * + * TIMER_FREQ_HZ =3D CPU_FREQ_HZ / CP0_COUNT_RATE =3D 200 MHz / 2 =3D 100 = MHz + * + * TIMER_PERIOD_NS =3D 1 / TIMER_FREQ_HZ =3D 10 ns + */ +#define CPU_FREQ_HZ_DEFAULT 200000000 +#define CP0_COUNT_RATE_DEFAULT 2 +#define TIMER_PERIOD 10 /* 1 / (CPU_FREQ_HZ / CP0_COUNT_RATE) = */ =20 /* MIPS R4K timer */ static void cpu_mips_timer_update(CPUMIPSState *env) --=20 2.26.2