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linux_dsm_epyc7002/drivers/clk/baikal-t1/Kconfig

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clk: Add Baikal-T1 CCU PLLs driver Baikal-T1 is supposed to be supplied with a high-frequency external oscillator. But in order to create signals suitable for each IP-block embedded into the SoC the oscillator output is primarily connected to a set of CCU PLLs. There are five of them to create clocks for the MIPS P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains. The last three domains though named by the biggest system interfaces in fact include nearly all of the rest SoC peripherals. Each of the PLLs is based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper (so called safe PLL' clocks switcher) to simplify the PLL configuration procedure. This driver creates the of-based hardware clocks to use them then in the corresponding subsystems. In order to simplify the driver code we split the functionality up into the PLLs clocks operations and hardware clocks declaration/registration procedures. Even though the PLLs are based on the same IP-core, they may have some differences. In particular, some CCU PLLs support the output clock change without gating them (like CPU or PCIe PLLs), while the others don't, some CCU PLLs are critical and aren't supposed to be gated. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for each PLL, which is then used to create a hardware clock with proper operations. Additionally debugfs-files are provided for each PLL' field to make sure the implemented rate-PLLs-dividers calculation algorithm is correct. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-4-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Silence sparse warning about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 05:20:55 +07:00
# SPDX-License-Identifier: GPL-2.0-only
config CLK_BAIKAL_T1
bool "Baikal-T1 Clocks Control Unit interface"
depends on (MIPS_BAIKAL_T1 && OF) || COMPILE_TEST
default MIPS_BAIKAL_T1
help
Clocks Control Unit is the core of Baikal-T1 SoC System Controller
responsible for the chip subsystems clocking and resetting. It
consists of multiple global clock domains, which can be reset by
means of the CCU control registers. These domains and devices placed
in them are fed with clocks generated by a hierarchy of PLLs,
configurable and fixed clock dividers. Enable this option to be able
to select Baikal-T1 CCU PLLs and Dividers drivers.
if CLK_BAIKAL_T1
config CLK_BT1_CCU_PLL
bool "Baikal-T1 CCU PLLs support"
select MFD_SYSCON
default MIPS_BAIKAL_T1
help
Enable this to support the PLLs embedded into the Baikal-T1 SoC
System Controller. These are five PLLs placed at the root of the
clocks hierarchy, right after an external reference oscillator
(normally of 25MHz). They are used to generate high frequency
signals, which are either directly wired to the consumers (like
CPUs, DDR, etc.) or passed over the clock dividers to be only
then used as an individual reference clock of a target device.
clk: Add Baikal-T1 CCU Dividers driver Nearly each Baikal-T1 IP-core is supposed to have a clock source of particular frequency. But since there are greater than five IP-blocks embedded into the SoC, the CCU PLLs can't fulfill all the needs. Baikal-T1 CCU provides a set of fixed and configurable clock dividers in order to generate a necessary signal for each chip sub-block. This driver creates the of-based hardware clocks for each divider available in Baikal-T1 CCU. The same way as for PLLs we split the functionality up into the clocks operations (gate, ungate, set rate, etc) and hardware clocks declaration/registration procedures. In accordance with the CCU documentation all its dividers are distributed into two CCU sub-blocks: AXI-bus and system devices reference clocks. The former sub-block is used to supply the clocks for AXI-bus interfaces (AXI clock domains) and the later one provides the SoC IP-cores reference clocks. Each sub-block is represented by a dedicated DT node, so they have different compatible strings to distinguish one from another. For some reason CCU provides the dividers of different types. Some dividers can be gateable some can't, some are fixed while the others are variable, some have special divider' limitations, some've got a non-standard register layout and so on. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for the dividers of each type with additional flags describing the block peculiarity. These descriptors are then used to create hardware clocks with proper operations. Some CCU dividers provide a way to reset a domain they generate a clock for. So the CCU AXI-bus and CCU system devices clock drivers also perform the reset controller registration. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-5-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Drop return from void function, silence sparse warnings about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 05:20:56 +07:00
config CLK_BT1_CCU_DIV
bool "Baikal-T1 CCU Dividers support"
select RESET_CONTROLLER
select MFD_SYSCON
default MIPS_BAIKAL_T1
help
Enable this to support the CCU dividers used to distribute clocks
between AXI-bus and system devices coming from CCU PLLs of Baikal-T1
SoC. CCU dividers can be either configurable or with fixed divider,
either gateable or ungateable. Some of the CCU dividers can be as well
used to reset the domains they're supplying clock to.
clk: Add Baikal-T1 CCU PLLs driver Baikal-T1 is supposed to be supplied with a high-frequency external oscillator. But in order to create signals suitable for each IP-block embedded into the SoC the oscillator output is primarily connected to a set of CCU PLLs. There are five of them to create clocks for the MIPS P5600 cores, an embedded DDR controller, SATA, Ethernet and PCIe domains. The last three domains though named by the biggest system interfaces in fact include nearly all of the rest SoC peripherals. Each of the PLLs is based on True Circuits TSMC CLN28HPM IP-core with an interface wrapper (so called safe PLL' clocks switcher) to simplify the PLL configuration procedure. This driver creates the of-based hardware clocks to use them then in the corresponding subsystems. In order to simplify the driver code we split the functionality up into the PLLs clocks operations and hardware clocks declaration/registration procedures. Even though the PLLs are based on the same IP-core, they may have some differences. In particular, some CCU PLLs support the output clock change without gating them (like CPU or PCIe PLLs), while the others don't, some CCU PLLs are critical and aren't supposed to be gated. In order to cover all of these cases the hardware clocks driver is designed with an info-descriptor pattern. So there are special static descriptors declared for each PLL, which is then used to create a hardware clock with proper operations. Additionally debugfs-files are provided for each PLL' field to make sure the implemented rate-PLLs-dividers calculation algorithm is correct. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200526222056.18072-4-Sergey.Semin@baikalelectronics.ru [sboyd@kernel.org: Silence sparse warning about initializing structs with NULL vs. integer] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2020-05-27 05:20:55 +07:00
endif
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