From: pavel@denx.de (Pavel Machek)
To: cip-dev@lists.cip-project.org
Subject: [cip-dev] [PATCH 4.19.y-cip 15/23] clk: renesas: rcar-gen3: Support Z and Z2 clocks with high frequency parents
Date: Tue, 16 Jul 2019 13:22:30 +0200 [thread overview]
Message-ID: <20190716112230.GB24157@amd> (raw)
In-Reply-To: <1563197408-59548-16-git-send-email-biju.das@bp.renesas.com>
Hi!
> Support Z and Z2 clocks with parent frequencies greater than UINT32_MAX Hz
> (~4.29GHz).
>
> The DIV_ROUND_CLOSEST_ULL() macro accepts a 64bit dividend and 32bit
> divisor. This leads to truncation of the divisor, which is the Z or Z2
> parent clock frequency in HZ, on platforms where frequency of that clock is
> greater than UINT32_MAX Hz.
>
> To resolve this problem the DIV64_U64_ROUND_CLOSEST() macro, which takes
> on an unsigned 64bit dividend and divisor, is used.
>
> An earlier version of this patch made use of the existing
> DIV_ROUND_CLOSEST() macro, which accepts the prevailing type of the
> dividend and divisor. However, this does not compile on 32bit systems, such
> as i386 and mips, when called with the types used at this call site, an
> unsigned long long dividend and unsigned long divisor.
> This work is in preparation for supporting the Z2 clock on the
> R-Car Gen3 E3 (r8a77990) SoC which has a 4.8GHz parent clock.
You still store "parent_rate" in "unsigned long". That is going to
overflow on 32-bit systems, right?
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2019-07-16 11:22 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 13:29 [cip-dev] [PATCH 4.19.y-cip 00/23] Clock enhancements Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 01/23] clk: renesas: r8a774a1: Add CPEX clock Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 02/23] clk: renesas: rcar-gen3: Set state when registering SD clocks Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 03/23] clk: renesas: rcar-gen3: Add documentation for " Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 04/23] clk: renesas: rcar-gen3: Add HS400 quirk for SD clock Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 05/23] clk: renesas: Remove usage of CLK_IS_BASIC Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 06/23] clk: renesas: r8a774a1: Add missing CANFD clock Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 07/23] clk: renesas: rcar-gen3: Factor out cpg_reg_modify() Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 08/23] clk: renesas: rcar-gen3: Add spinlock Biju Das
2019-07-16 11:17 ` Pavel Machek
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 09/23] clk: renesas: r8a774a1: Fix LAST_DT_CORE_CLK Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 10/23] clk: renesas: rcar-gen3: Pass name/offset to cpg_sd_clk_register() Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 11/23] clk: renesas: rcar-gen3: Parameterise Z and Z2 clock fixed divisor Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 12/23] clk: renesas: rcar-gen3: Parameterise Z and Z2 clock offset Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 13/23] clk: renesas: rcar-gen3: Remove CLK_TYPE_GEN3_Z2 Biju Das
2019-07-15 13:29 ` [cip-dev] [PATCH 4.19.y-cip 14/23] math64: New DIV64_U64_ROUND_CLOSEST helper Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 15/23] clk: renesas: rcar-gen3: Support Z and Z2 clocks with high frequency parents Biju Das
2019-07-16 11:22 ` Pavel Machek [this message]
2019-07-16 12:01 ` Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 16/23] clk: renesas: r8a774c0: Add Z2 clock Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 17/23] clk: renesas: rcar-gen3: Correct parent clock of EHCI/OHCI Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 18/23] clk: renesas: rcar-gen3: Correct parent clock of HS-USB Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 19/23] clk: renesas: rcar-gen3: Correct parent clock of SYS-DMAC Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 20/23] clk: renesas: rcar-gen3: Correct parent clock of Audio-DMAC Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 21/23] clk: renesas: rcar-gen3: Fix cpg_sd_clock_round_rate() return value Biju Das
2019-07-16 11:24 ` Pavel Machek
2019-07-16 11:56 ` Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 22/23] clk: renesas: rcar-gen3: Remove unused variable Biju Das
2019-07-15 13:30 ` [cip-dev] [PATCH 4.19.y-cip 23/23] arm64: dts: renesas: r8a774c0: Add OPPs table for cpu devices Biju Das
2019-07-15 19:50 ` [cip-dev] [PATCH 4.19.y-cip 00/23] Clock enhancements Pavel Machek
2019-07-15 21:57 ` Pavel Machek
2019-07-16 6:45 ` Biju Das
2019-07-16 11:28 ` Pavel Machek
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