/* * Copyright (c) 2015 Endless Mobile, Inc. * Author: Carlo Caione <carlo@endlessm.com> * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program. If not, see <http://www.gnu.org/licenses/>. */ /* * CPU clock path: * * +-[/N]-----|3| * MUX2 +--[/3]-+----------|2| MUX1 * [sys_pll]---|1| |--[/2]------------|1|-|1| * | |---+------------------|0| | |----- [a5_clk] * +--|0| | | * [xtal]---+-------------------------------|0| * * * */ #include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of_address.h> #include <linux/slab.h> #include <linux/clk.h> #include <linux/clk-provider.h> #define MESON_CPU_CLK_CNTL1 0x00 #define MESON_CPU_CLK_CNTL 0x40 #define MESON_CPU_CLK_MUX1 BIT(7) #define MESON_CPU_CLK_MUX2 BIT(0) #define MESON_N_WIDTH 9 #define MESON_N_SHIFT 20 #define MESON_SEL_WIDTH 2 #define MESON_SEL_SHIFT 2 #include "clkc.h" struct meson_clk_cpu { struct notifier_block clk_nb; const struct clk_div_table *div_table; struct clk_hw hw; void __iomem *base; u16 reg_off; }; #define to_meson_clk_cpu_hw(_hw) container_of(_hw, struct meson_clk_cpu, hw) #define to_meson_clk_cpu_nb(_nb) container_of(_nb, struct meson_clk_cpu, clk_nb) static long meson_clk_cpu_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *prate) { struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_hw(hw); return divider_round_rate(hw, rate, prate, clk_cpu->div_table, MESON_N_WIDTH, CLK_DIVIDER_ROUND_CLOSEST); } static int meson_clk_cpu_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_hw(hw); unsigned int div, sel, N = 0; u32 reg; div = DIV_ROUND_UP(parent_rate, rate); if (div <= 3) { sel = div - 1; } else { sel = 3; N = div / 2; } reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL1); reg = PARM_SET(MESON_N_WIDTH, MESON_N_SHIFT, reg, N); writel(reg, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL1); reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); reg = PARM_SET(MESON_SEL_WIDTH, MESON_SEL_SHIFT, reg, sel); writel(reg, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); return 0; } static unsigned long meson_clk_cpu_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_hw(hw); unsigned int N, sel; unsigned int div = 1; u32 reg; reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL1); N = PARM_GET(MESON_N_WIDTH, MESON_N_SHIFT, reg); reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); sel = PARM_GET(MESON_SEL_WIDTH, MESON_SEL_SHIFT, reg); if (sel < 3) div = sel + 1; else div = 2 * N; return parent_rate / div; } static int meson_clk_cpu_pre_rate_change(struct meson_clk_cpu *clk_cpu, struct clk_notifier_data *ndata) { u32 cpu_clk_cntl; /* switch MUX1 to xtal */ cpu_clk_cntl = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); cpu_clk_cntl &= ~MESON_CPU_CLK_MUX1; writel(cpu_clk_cntl, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); udelay(100); /* switch MUX2 to sys-pll */ cpu_clk_cntl |= MESON_CPU_CLK_MUX2; writel(cpu_clk_cntl, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); return 0; } static int meson_clk_cpu_post_rate_change(struct meson_clk_cpu *clk_cpu, struct clk_notifier_data *ndata) { u32 cpu_clk_cntl; /* switch MUX1 to divisors' output */ cpu_clk_cntl = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); cpu_clk_cntl |= MESON_CPU_CLK_MUX1; writel(cpu_clk_cntl, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL); udelay(100); return 0; } /* * This clock notifier is called when the frequency of the of the parent * PLL clock is to be changed. We use the xtal input as temporary parent * while the PLL frequency is stabilized. */ static int meson_clk_cpu_notifier_cb(struct notifier_block *nb, unsigned long event, void *data) { struct clk_notifier_data *ndata = data; struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_nb(nb); int ret = 0; if (event == PRE_RATE_CHANGE) ret = meson_clk_cpu_pre_rate_change(clk_cpu, ndata); else if (event == POST_RATE_CHANGE) ret = meson_clk_cpu_post_rate_change(clk_cpu, ndata); return notifier_from_errno(ret); } static const struct clk_ops meson_clk_cpu_ops = { .recalc_rate = meson_clk_cpu_recalc_rate, .round_rate = meson_clk_cpu_round_rate, .set_rate = meson_clk_cpu_set_rate, }; struct clk *meson_clk_register_cpu(const struct clk_conf *clk_conf, void __iomem *reg_base, spinlock_t *lock) { struct clk *clk; struct clk *pclk; struct meson_clk_cpu *clk_cpu; struct clk_init_data init; int ret; clk_cpu = kzalloc(sizeof(*clk_cpu), GFP_KERNEL); if (!clk_cpu) return ERR_PTR(-ENOMEM); clk_cpu->base = reg_base; clk_cpu->reg_off = clk_conf->reg_off; clk_cpu->div_table = clk_conf->conf.div_table; clk_cpu->clk_nb.notifier_call = meson_clk_cpu_notifier_cb; init.name = clk_conf->clk_name; init.ops = &meson_clk_cpu_ops; init.flags = clk_conf->flags | CLK_GET_RATE_NOCACHE; init.flags |= CLK_SET_RATE_PARENT; init.parent_names = clk_conf->clks_parent; init.num_parents = 1; clk_cpu->hw.init = &init; pclk = __clk_lookup(clk_conf->clks_parent[0]); if (!pclk) { pr_err("%s: could not lookup parent clock %s\n", __func__, clk_conf->clks_parent[0]); ret = -EINVAL; goto free_clk; } ret = clk_notifier_register(pclk, &clk_cpu->clk_nb); if (ret) { pr_err("%s: failed to register clock notifier for %s\n", __func__, clk_conf->clk_name); goto free_clk; } clk = clk_register(NULL, &clk_cpu->hw); if (IS_ERR(clk)) { ret = PTR_ERR(clk); goto unregister_clk_nb; } return clk; unregister_clk_nb: clk_notifier_unregister(pclk, &clk_cpu->clk_nb); free_clk: kfree(clk_cpu); return ERR_PTR(ret); }