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c4e05443b6
In accordance with the way the MIPS platform is normally design there are
only six clock sources which need to be available on the kernel start in
order to one end up booting correctly:
+ CPU PLL: needed by the r4k and MIPS GIC timer drivers. The former one is
initialized by the arch code, while the later one is implemented in the
mips-gic-timer.c driver as the OF-declared timer.
+ PCIe PLL: required as a parental clock source for the APB/timer domains.
+ APB clock: needed in order to access all the SoC CSRs at least for the
timer OF-declared drivers.
+ APB Timer{0-2} clocks: these are the DW APB timers which drivers
dw_apb_timer_of.c are implemented as the OF-declared timers.
So as long as the clocks above are available early the kernel will
normally work. Let's convert the Baikal-T1 CCU drivers to the platform
device drivers keeping that in mind.
Generally speaking the conversion isn't that complicated since the driver
infrastructure has been designed as flexible enough for that. First we
need to add a new PLL/Divider clock features flag which indicates the
corresponding clock source as a basic one and that clock sources will be
available on the kernel early boot stages. Second the internal PLL/Divider
descriptors need to be initialized with -EPROBE_DEFER value as the
corresponding clock source is unavailable at the early stages. They will
be allocated and initialized on the Baikal-T1 clock platform driver probe
procedure. Finally the already available PLL/Divider init functions need
to be split up into two ones: init procedure performed in the framework of
the OF-declared clock initialization (of_clk_init()), and the probe
procedure called by the platform devices bus driver. Note the later method
will just continue the system clocks initialization started in the former
one.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20220929225402.9696-9-Sergey.Semin@baikalelectronics.ru
[sboyd@kernel.org: Remove module things because the Kconfig is still
bool]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
122 lines
3.3 KiB
C
122 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
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*
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* Baikal-T1 CCU Dividers interface driver
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*/
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#ifndef __CLK_BT1_CCU_DIV_H__
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#define __CLK_BT1_CCU_DIV_H__
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#include <linux/clk-provider.h>
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#include <linux/spinlock.h>
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#include <linux/regmap.h>
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#include <linux/bits.h>
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#include <linux/of.h>
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/*
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* CCU Divider private clock IDs
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* @CCU_SYS_SATA_CLK: CCU SATA internal clock
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* @CCU_SYS_XGMAC_CLK: CCU XGMAC internal clock
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*/
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#define CCU_SYS_SATA_CLK -1
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#define CCU_SYS_XGMAC_CLK -2
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/*
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* CCU Divider private flags
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* @CCU_DIV_BASIC: Basic divider clock required by the kernel as early as
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* possible.
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* @CCU_DIV_SKIP_ONE: Due to some reason divider can't be set to 1.
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* It can be 0 though, which is functionally the same.
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* @CCU_DIV_SKIP_ONE_TO_THREE: For some reason divider can't be within [1,3].
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* It can be either 0 or greater than 3.
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* @CCU_DIV_LOCK_SHIFTED: Find lock-bit at non-standard position.
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* @CCU_DIV_RESET_DOMAIN: There is a clock domain reset handle.
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*/
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#define CCU_DIV_BASIC BIT(0)
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#define CCU_DIV_SKIP_ONE BIT(1)
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#define CCU_DIV_SKIP_ONE_TO_THREE BIT(2)
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#define CCU_DIV_LOCK_SHIFTED BIT(3)
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#define CCU_DIV_RESET_DOMAIN BIT(4)
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/*
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* enum ccu_div_type - CCU Divider types
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* @CCU_DIV_VAR: Clocks gate with variable divider.
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* @CCU_DIV_GATE: Clocks gate with fixed divider.
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* @CCU_DIV_BUF: Clock gate with no divider.
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* @CCU_DIV_FIXED: Ungateable clock with fixed divider.
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*/
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enum ccu_div_type {
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CCU_DIV_VAR,
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CCU_DIV_GATE,
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CCU_DIV_BUF,
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CCU_DIV_FIXED
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};
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/*
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* struct ccu_div_init_data - CCU Divider initialization data
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* @id: Clocks private identifier.
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* @name: Clocks name.
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* @parent_name: Parent clocks name in a fw node.
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* @base: Divider register base address with respect to the sys_regs base.
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* @sys_regs: Baikal-T1 System Controller registers map.
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* @np: Pointer to the node describing the CCU Dividers.
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* @type: CCU divider type (variable, fixed with and without gate).
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* @width: Divider width if it's variable.
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* @divider: Divider fixed value.
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* @flags: CCU Divider clock flags.
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* @features: CCU Divider private features.
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*/
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struct ccu_div_init_data {
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unsigned int id;
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const char *name;
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const char *parent_name;
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unsigned int base;
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struct regmap *sys_regs;
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struct device_node *np;
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enum ccu_div_type type;
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union {
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unsigned int width;
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unsigned int divider;
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};
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unsigned long flags;
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unsigned long features;
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};
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/*
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* struct ccu_div - CCU Divider descriptor
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* @hw: clk_hw of the divider.
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* @id: Clock private identifier.
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* @reg_ctl: Divider control register base address.
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* @sys_regs: Baikal-T1 System Controller registers map.
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* @lock: Divider state change spin-lock.
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* @mask: Divider field mask.
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* @divider: Divider fixed value.
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* @flags: Divider clock flags.
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* @features: CCU Divider private features.
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*/
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struct ccu_div {
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struct clk_hw hw;
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unsigned int id;
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unsigned int reg_ctl;
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struct regmap *sys_regs;
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spinlock_t lock;
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union {
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u32 mask;
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unsigned int divider;
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};
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unsigned long flags;
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unsigned long features;
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};
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#define to_ccu_div(_hw) container_of(_hw, struct ccu_div, hw)
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static inline struct clk_hw *ccu_div_get_clk_hw(struct ccu_div *div)
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{
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return div ? &div->hw : NULL;
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}
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struct ccu_div *ccu_div_hw_register(const struct ccu_div_init_data *init);
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void ccu_div_hw_unregister(struct ccu_div *div);
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#endif /* __CLK_BT1_CCU_DIV_H__ */
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