Date: Wed, 21 Jun 2023 18:59:15 +0300 From: titus <titus@edc.ro> To: Emmanuel Vadot <manu@bidouilliste.com> Cc: freebsd-arm@freebsd.org Subject: Re: h616 clocks Message-ID: <C52AEC69-088A-45F9-924E-CBE7380FA957@edc.ro> In-Reply-To: <20230621155551.5c6a2db2ad87c08c7d2ec7f2@bidouilliste.com> References: <E44D2C76-2FD5-4DE3-9111-3BEB508755E0@edc.ro> <20230621155551.5c6a2db2ad87c08c7d2ec7f2@bidouilliste.com>
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Thanks for the answer.=20 the line was =E2=80=9Cadjusted=E2=80=9D copied from the linux driver=20 im not sure which clocks are mandatory to have a h616 board working = (uart, sdmmc, usb, ethernet will suffice)=20 i just saw that there are more clocks in the linux driver than in the = freebsd h6 driver but probably the ones defined for h6 in freebsd will = suffice for my goal i do not have a h616 board yet but i will get one in several days and i = hopefully can test its not quite a development board but an android tv box which should = have the uart pins/pads exposed on the mb so i can hook the serial uart = wires > On Jun 21, 2023, at 4:55 PM, Emmanuel Vadot <manu@bidouilliste.com> = wrote: >=20 >=20 > Hello Titus, >=20 > On Wed, 21 Jun 2023 10:58:17 +0300 > titus <titus@edc.ro> wrote: >=20 >> I?m trying to add support for allwinner H616 ccu >> I downloaded H616 user manual and i mostly can figure out differences = from allwinner H6 but i have a question >> how is the CCU_GATE clock parent assigned to a specifc ccu gate - = there is no indication in the manual >=20 > There is, you need to look at the system bus tree (page 90 for the H6 > and page 46 for the H616). >=20 >> for example=20 >> CCU_GATE(CLK_BUS_DE, "bus-de", "psi-ahb1-ahb2", 0x60c, 0) >> the manual says that >> 0x060C DE Bus Gating Reset Register (Default Value: 0x0000_0000) has = bit 0 as DE_GATING and bit 16 as DE_RST >> but why is psi-ahb1-ahb2 chosen as parent ? (can?t find any reference = in the manual) >=20 > No idea where you got this example as we don't have this clock defined > in FreeBSD so a bit hard to answer to this specific example. > But indeed that looks correct as the DE engine sits on the PSI2AHB bus > which is on the PSI bus. > If you look at page 91 in the H6 user manual you can see that AHB1 and > AHB2 are both the same clock and equal to the PSI one, which itself is > created from 4 possible parents (OSC24M, CCU_32K, RC16M and PLL_PERI0) > and two factors (N and M). > Clocks can be a bit hard to understand, especially clock topology and > Allwinner doesn't make it better by not having a full clock topo table > in their docs usually. So open the doc 3 or 4 times and go back and > forth reading the clock tree and register definitions. > Also don't hesitate to ask more questions I'll see if I can help. >=20 > Cheers, >=20 > --=20 > Emmanuel Vadot <manu@bidouilliste.com> <manu@freebsd.org> >=20 >=20
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