diff options
Diffstat (limited to 'drivers/clk/samsung/clk-cpu.c')
| -rw-r--r-- | drivers/clk/samsung/clk-cpu.c | 471 |
1 files changed, 471 insertions, 0 deletions
diff --git a/drivers/clk/samsung/clk-cpu.c b/drivers/clk/samsung/clk-cpu.c new file mode 100644 index 000000000..00ef4d1b0 --- /dev/null +++ b/drivers/clk/samsung/clk-cpu.c @@ -0,0 +1,471 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2014 Samsung Electronics Co., Ltd. + * Author: Thomas Abraham <thomas.ab@samsung.com> + * + * Copyright (c) 2015 Samsung Electronics Co., Ltd. + * Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> + * + * This file contains the utility function to register CPU clock for Samsung + * Exynos platforms. A CPU clock is defined as a clock supplied to a CPU or a + * group of CPUs. The CPU clock is typically derived from a hierarchy of clock + * blocks which includes mux and divider blocks. There are a number of other + * auxiliary clocks supplied to the CPU domain such as the debug blocks and AXI + * clock for CPU domain. The rates of these auxiliary clocks are related to the + * CPU clock rate and this relation is usually specified in the hardware manual + * of the SoC or supplied after the SoC characterization. + * + * The below implementation of the CPU clock allows the rate changes of the CPU + * clock and the corresponding rate changes of the auxillary clocks of the CPU + * domain. The platform clock driver provides a clock register configuration + * for each configurable rate which is then used to program the clock hardware + * registers to acheive a fast co-oridinated rate change for all the CPU domain + * clocks. + * + * On a rate change request for the CPU clock, the rate change is propagated + * upto the PLL supplying the clock to the CPU domain clock blocks. While the + * CPU domain PLL is reconfigured, the CPU domain clocks are driven using an + * alternate clock source. If required, the alternate clock source is divided + * down in order to keep the output clock rate within the previous OPP limits. +*/ + +#include <linux/errno.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include "clk-cpu.h" + +#define E4210_SRC_CPU 0x0 +#define E4210_STAT_CPU 0x200 +#define E4210_DIV_CPU0 0x300 +#define E4210_DIV_CPU1 0x304 +#define E4210_DIV_STAT_CPU0 0x400 +#define E4210_DIV_STAT_CPU1 0x404 + +#define E5433_MUX_SEL2 0x008 +#define E5433_MUX_STAT2 0x208 +#define E5433_DIV_CPU0 0x400 +#define E5433_DIV_CPU1 0x404 +#define E5433_DIV_STAT_CPU0 0x500 +#define E5433_DIV_STAT_CPU1 0x504 + +#define E4210_DIV0_RATIO0_MASK 0x7 +#define E4210_DIV1_HPM_MASK (0x7 << 4) +#define E4210_DIV1_COPY_MASK (0x7 << 0) +#define E4210_MUX_HPM_MASK (1 << 20) +#define E4210_DIV0_ATB_SHIFT 16 +#define E4210_DIV0_ATB_MASK (DIV_MASK << E4210_DIV0_ATB_SHIFT) + +#define MAX_DIV 8 +#define DIV_MASK 7 +#define DIV_MASK_ALL 0xffffffff +#define MUX_MASK 7 + +/* + * Helper function to wait until divider(s) have stabilized after the divider + * value has changed. + */ +static void wait_until_divider_stable(void __iomem *div_reg, unsigned long mask) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(10); + + do { + if (!(readl(div_reg) & mask)) + return; + } while (time_before(jiffies, timeout)); + + if (!(readl(div_reg) & mask)) + return; + + pr_err("%s: timeout in divider stablization\n", __func__); +} + +/* + * Helper function to wait until mux has stabilized after the mux selection + * value was changed. + */ +static void wait_until_mux_stable(void __iomem *mux_reg, u32 mux_pos, + unsigned long mux_value) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(10); + + do { + if (((readl(mux_reg) >> mux_pos) & MUX_MASK) == mux_value) + return; + } while (time_before(jiffies, timeout)); + + if (((readl(mux_reg) >> mux_pos) & MUX_MASK) == mux_value) + return; + + pr_err("%s: re-parenting mux timed-out\n", __func__); +} + +/* common round rate callback useable for all types of CPU clocks */ +static long exynos_cpuclk_round_rate(struct clk_hw *hw, + unsigned long drate, unsigned long *prate) +{ + struct clk_hw *parent = clk_hw_get_parent(hw); + *prate = clk_hw_round_rate(parent, drate); + return *prate; +} + +/* common recalc rate callback useable for all types of CPU clocks */ +static unsigned long exynos_cpuclk_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + /* + * The CPU clock output (armclk) rate is the same as its parent + * rate. Although there exist certain dividers inside the CPU + * clock block that could be used to divide the parent clock, + * the driver does not make use of them currently, except during + * frequency transitions. + */ + return parent_rate; +} + +static const struct clk_ops exynos_cpuclk_clk_ops = { + .recalc_rate = exynos_cpuclk_recalc_rate, + .round_rate = exynos_cpuclk_round_rate, +}; + +/* + * Helper function to set the 'safe' dividers for the CPU clock. The parameters + * div and mask contain the divider value and the register bit mask of the + * dividers to be programmed. + */ +static void exynos_set_safe_div(void __iomem *base, unsigned long div, + unsigned long mask) +{ + unsigned long div0; + + div0 = readl(base + E4210_DIV_CPU0); + div0 = (div0 & ~mask) | (div & mask); + writel(div0, base + E4210_DIV_CPU0); + wait_until_divider_stable(base + E4210_DIV_STAT_CPU0, mask); +} + +/* handler for pre-rate change notification from parent clock */ +static int exynos_cpuclk_pre_rate_change(struct clk_notifier_data *ndata, + struct exynos_cpuclk *cpuclk, void __iomem *base) +{ + const struct exynos_cpuclk_cfg_data *cfg_data = cpuclk->cfg; + unsigned long alt_prate = clk_hw_get_rate(cpuclk->alt_parent); + unsigned long alt_div = 0, alt_div_mask = DIV_MASK; + unsigned long div0, div1 = 0, mux_reg; + unsigned long flags; + + /* find out the divider values to use for clock data */ + while ((cfg_data->prate * 1000) != ndata->new_rate) { + if (cfg_data->prate == 0) + return -EINVAL; + cfg_data++; + } + + spin_lock_irqsave(cpuclk->lock, flags); + + /* + * For the selected PLL clock frequency, get the pre-defined divider + * values. If the clock for sclk_hpm is not sourced from apll, then + * the values for DIV_COPY and DIV_HPM dividers need not be set. + */ + div0 = cfg_data->div0; + if (cpuclk->flags & CLK_CPU_HAS_DIV1) { + div1 = cfg_data->div1; + if (readl(base + E4210_SRC_CPU) & E4210_MUX_HPM_MASK) + div1 = readl(base + E4210_DIV_CPU1) & + (E4210_DIV1_HPM_MASK | E4210_DIV1_COPY_MASK); + } + + /* + * If the old parent clock speed is less than the clock speed of + * the alternate parent, then it should be ensured that at no point + * the armclk speed is more than the old_prate until the dividers are + * set. Also workaround the issue of the dividers being set to lower + * values before the parent clock speed is set to new lower speed + * (this can result in too high speed of armclk output clocks). + */ + if (alt_prate > ndata->old_rate || ndata->old_rate > ndata->new_rate) { + unsigned long tmp_rate = min(ndata->old_rate, ndata->new_rate); + + alt_div = DIV_ROUND_UP(alt_prate, tmp_rate) - 1; + WARN_ON(alt_div >= MAX_DIV); + + if (cpuclk->flags & CLK_CPU_NEEDS_DEBUG_ALT_DIV) { + /* + * In Exynos4210, ATB clock parent is also mout_core. So + * ATB clock also needs to be mantained at safe speed. + */ + alt_div |= E4210_DIV0_ATB_MASK; + alt_div_mask |= E4210_DIV0_ATB_MASK; + } + exynos_set_safe_div(base, alt_div, alt_div_mask); + div0 |= alt_div; + } + + /* select sclk_mpll as the alternate parent */ + mux_reg = readl(base + E4210_SRC_CPU); + writel(mux_reg | (1 << 16), base + E4210_SRC_CPU); + wait_until_mux_stable(base + E4210_STAT_CPU, 16, 2); + + /* alternate parent is active now. set the dividers */ + writel(div0, base + E4210_DIV_CPU0); + wait_until_divider_stable(base + E4210_DIV_STAT_CPU0, DIV_MASK_ALL); + + if (cpuclk->flags & CLK_CPU_HAS_DIV1) { + writel(div1, base + E4210_DIV_CPU1); + wait_until_divider_stable(base + E4210_DIV_STAT_CPU1, + DIV_MASK_ALL); + } + + spin_unlock_irqrestore(cpuclk->lock, flags); + return 0; +} + +/* handler for post-rate change notification from parent clock */ +static int exynos_cpuclk_post_rate_change(struct clk_notifier_data *ndata, + struct exynos_cpuclk *cpuclk, void __iomem *base) +{ + const struct exynos_cpuclk_cfg_data *cfg_data = cpuclk->cfg; + unsigned long div = 0, div_mask = DIV_MASK; + unsigned long mux_reg; + unsigned long flags; + + /* find out the divider values to use for clock data */ + if (cpuclk->flags & CLK_CPU_NEEDS_DEBUG_ALT_DIV) { + while ((cfg_data->prate * 1000) != ndata->new_rate) { + if (cfg_data->prate == 0) + return -EINVAL; + cfg_data++; + } + } + + spin_lock_irqsave(cpuclk->lock, flags); + + /* select mout_apll as the alternate parent */ + mux_reg = readl(base + E4210_SRC_CPU); + writel(mux_reg & ~(1 << 16), base + E4210_SRC_CPU); + wait_until_mux_stable(base + E4210_STAT_CPU, 16, 1); + + if (cpuclk->flags & CLK_CPU_NEEDS_DEBUG_ALT_DIV) { + div |= (cfg_data->div0 & E4210_DIV0_ATB_MASK); + div_mask |= E4210_DIV0_ATB_MASK; + } + + exynos_set_safe_div(base, div, div_mask); + spin_unlock_irqrestore(cpuclk->lock, flags); + return 0; +} + +/* + * Helper function to set the 'safe' dividers for the CPU clock. The parameters + * div and mask contain the divider value and the register bit mask of the + * dividers to be programmed. + */ +static void exynos5433_set_safe_div(void __iomem *base, unsigned long div, + unsigned long mask) +{ + unsigned long div0; + + div0 = readl(base + E5433_DIV_CPU0); + div0 = (div0 & ~mask) | (div & mask); + writel(div0, base + E5433_DIV_CPU0); + wait_until_divider_stable(base + E5433_DIV_STAT_CPU0, mask); +} + +/* handler for pre-rate change notification from parent clock */ +static int exynos5433_cpuclk_pre_rate_change(struct clk_notifier_data *ndata, + struct exynos_cpuclk *cpuclk, void __iomem *base) +{ + const struct exynos_cpuclk_cfg_data *cfg_data = cpuclk->cfg; + unsigned long alt_prate = clk_hw_get_rate(cpuclk->alt_parent); + unsigned long alt_div = 0, alt_div_mask = DIV_MASK; + unsigned long div0, div1 = 0, mux_reg; + unsigned long flags; + + /* find out the divider values to use for clock data */ + while ((cfg_data->prate * 1000) != ndata->new_rate) { + if (cfg_data->prate == 0) + return -EINVAL; + cfg_data++; + } + + spin_lock_irqsave(cpuclk->lock, flags); + + /* + * For the selected PLL clock frequency, get the pre-defined divider + * values. + */ + div0 = cfg_data->div0; + div1 = cfg_data->div1; + + /* + * If the old parent clock speed is less than the clock speed of + * the alternate parent, then it should be ensured that at no point + * the armclk speed is more than the old_prate until the dividers are + * set. Also workaround the issue of the dividers being set to lower + * values before the parent clock speed is set to new lower speed + * (this can result in too high speed of armclk output clocks). + */ + if (alt_prate > ndata->old_rate || ndata->old_rate > ndata->new_rate) { + unsigned long tmp_rate = min(ndata->old_rate, ndata->new_rate); + + alt_div = DIV_ROUND_UP(alt_prate, tmp_rate) - 1; + WARN_ON(alt_div >= MAX_DIV); + + exynos5433_set_safe_div(base, alt_div, alt_div_mask); + div0 |= alt_div; + } + + /* select the alternate parent */ + mux_reg = readl(base + E5433_MUX_SEL2); + writel(mux_reg | 1, base + E5433_MUX_SEL2); + wait_until_mux_stable(base + E5433_MUX_STAT2, 0, 2); + + /* alternate parent is active now. set the dividers */ + writel(div0, base + E5433_DIV_CPU0); + wait_until_divider_stable(base + E5433_DIV_STAT_CPU0, DIV_MASK_ALL); + + writel(div1, base + E5433_DIV_CPU1); + wait_until_divider_stable(base + E5433_DIV_STAT_CPU1, DIV_MASK_ALL); + + spin_unlock_irqrestore(cpuclk->lock, flags); + return 0; +} + +/* handler for post-rate change notification from parent clock */ +static int exynos5433_cpuclk_post_rate_change(struct clk_notifier_data *ndata, + struct exynos_cpuclk *cpuclk, void __iomem *base) +{ + unsigned long div = 0, div_mask = DIV_MASK; + unsigned long mux_reg; + unsigned long flags; + + spin_lock_irqsave(cpuclk->lock, flags); + + /* select apll as the alternate parent */ + mux_reg = readl(base + E5433_MUX_SEL2); + writel(mux_reg & ~1, base + E5433_MUX_SEL2); + wait_until_mux_stable(base + E5433_MUX_STAT2, 0, 1); + + exynos5433_set_safe_div(base, div, div_mask); + spin_unlock_irqrestore(cpuclk->lock, flags); + return 0; +} + +/* + * This notifier function is called for the pre-rate and post-rate change + * notifications of the parent clock of cpuclk. + */ +static int exynos_cpuclk_notifier_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct exynos_cpuclk *cpuclk; + void __iomem *base; + int err = 0; + + cpuclk = container_of(nb, struct exynos_cpuclk, clk_nb); + base = cpuclk->ctrl_base; + + if (event == PRE_RATE_CHANGE) + err = exynos_cpuclk_pre_rate_change(ndata, cpuclk, base); + else if (event == POST_RATE_CHANGE) + err = exynos_cpuclk_post_rate_change(ndata, cpuclk, base); + + return notifier_from_errno(err); +} + +/* + * This notifier function is called for the pre-rate and post-rate change + * notifications of the parent clock of cpuclk. + */ +static int exynos5433_cpuclk_notifier_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct exynos_cpuclk *cpuclk; + void __iomem *base; + int err = 0; + + cpuclk = container_of(nb, struct exynos_cpuclk, clk_nb); + base = cpuclk->ctrl_base; + + if (event == PRE_RATE_CHANGE) + err = exynos5433_cpuclk_pre_rate_change(ndata, cpuclk, base); + else if (event == POST_RATE_CHANGE) + err = exynos5433_cpuclk_post_rate_change(ndata, cpuclk, base); + + return notifier_from_errno(err); +} + +/* helper function to register a CPU clock */ +int __init exynos_register_cpu_clock(struct samsung_clk_provider *ctx, + unsigned int lookup_id, const char *name, + const struct clk_hw *parent, const struct clk_hw *alt_parent, + unsigned long offset, const struct exynos_cpuclk_cfg_data *cfg, + unsigned long num_cfgs, unsigned long flags) +{ + struct exynos_cpuclk *cpuclk; + struct clk_init_data init; + const char *parent_name; + int ret = 0; + + if (IS_ERR(parent) || IS_ERR(alt_parent)) { + pr_err("%s: invalid parent clock(s)\n", __func__); + return -EINVAL; + } + + cpuclk = kzalloc(sizeof(*cpuclk), GFP_KERNEL); + if (!cpuclk) + return -ENOMEM; + + parent_name = clk_hw_get_name(parent); + + init.name = name; + init.flags = CLK_SET_RATE_PARENT; + init.parent_names = &parent_name; + init.num_parents = 1; + init.ops = &exynos_cpuclk_clk_ops; + + cpuclk->alt_parent = alt_parent; + cpuclk->hw.init = &init; + cpuclk->ctrl_base = ctx->reg_base + offset; + cpuclk->lock = &ctx->lock; + cpuclk->flags = flags; + if (flags & CLK_CPU_HAS_E5433_REGS_LAYOUT) + cpuclk->clk_nb.notifier_call = exynos5433_cpuclk_notifier_cb; + else + cpuclk->clk_nb.notifier_call = exynos_cpuclk_notifier_cb; + + + ret = clk_notifier_register(parent->clk, &cpuclk->clk_nb); + if (ret) { + pr_err("%s: failed to register clock notifier for %s\n", + __func__, name); + goto free_cpuclk; + } + + cpuclk->cfg = kmemdup(cfg, sizeof(*cfg) * num_cfgs, GFP_KERNEL); + if (!cpuclk->cfg) { + ret = -ENOMEM; + goto unregister_clk_nb; + } + + ret = clk_hw_register(NULL, &cpuclk->hw); + if (ret) { + pr_err("%s: could not register cpuclk %s\n", __func__, name); + goto free_cpuclk_data; + } + + samsung_clk_add_lookup(ctx, &cpuclk->hw, lookup_id); + return 0; + +free_cpuclk_data: + kfree(cpuclk->cfg); +unregister_clk_nb: + clk_notifier_unregister(parent->clk, &cpuclk->clk_nb); +free_cpuclk: + kfree(cpuclk); + return ret; +} |