diff options
Diffstat (limited to 'drivers/clk/tegra/clk-tegra-super-cclk.c')
| -rw-r--r-- | drivers/clk/tegra/clk-tegra-super-cclk.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/clk/tegra/clk-tegra-super-cclk.c b/drivers/clk/tegra/clk-tegra-super-cclk.c new file mode 100644 index 000000000000..a03119c30456 --- /dev/null +++ b/drivers/clk/tegra/clk-tegra-super-cclk.c @@ -0,0 +1,212 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Based on clk-super.c + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * + * Based on older tegra20-cpufreq driver by Colin Cross <ccross@google.com> + * Copyright (C) 2010 Google, Inc. + * + * Author: Dmitry Osipenko <digetx@gmail.com> + * Copyright (C) 2019 GRATE-DRIVER project + */ + +#include <linux/bits.h> +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/types.h> + +#include "clk.h" + +#define PLLP_INDEX 4 +#define PLLX_INDEX 8 + +#define SUPER_CDIV_ENB BIT(31) + +static struct tegra_clk_super_mux *cclk_super; +static bool cclk_on_pllx; + +static u8 cclk_super_get_parent(struct clk_hw *hw) +{ + return tegra_clk_super_ops.get_parent(hw); +} + +static int cclk_super_set_parent(struct clk_hw *hw, u8 index) +{ + return tegra_clk_super_ops.set_parent(hw, index); +} + +static int cclk_super_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + return tegra_clk_super_ops.set_rate(hw, rate, parent_rate); +} + +static unsigned long cclk_super_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + if (cclk_super_get_parent(hw) == PLLX_INDEX) + return parent_rate; + + return tegra_clk_super_ops.recalc_rate(hw, parent_rate); +} + +static int cclk_super_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct clk_hw *pllp_hw = clk_hw_get_parent_by_index(hw, PLLP_INDEX); + struct clk_hw *pllx_hw = clk_hw_get_parent_by_index(hw, PLLX_INDEX); + struct tegra_clk_super_mux *super = to_clk_super_mux(hw); + unsigned long pllp_rate; + long rate = req->rate; + + if (WARN_ON_ONCE(!pllp_hw || !pllx_hw)) + return -EINVAL; + + /* + * Switch parent to PLLP for all CCLK rates that are suitable for PLLP. + * PLLX will be disabled in this case, saving some power. + */ + pllp_rate = clk_hw_get_rate(pllp_hw); + + if (rate <= pllp_rate) { + if (super->flags & TEGRA20_SUPER_CLK) + rate = pllp_rate; + else + rate = tegra_clk_super_ops.round_rate(hw, rate, + &pllp_rate); + + req->best_parent_rate = pllp_rate; + req->best_parent_hw = pllp_hw; + req->rate = rate; + } else { + rate = clk_hw_round_rate(pllx_hw, rate); + req->best_parent_rate = rate; + req->best_parent_hw = pllx_hw; + req->rate = rate; + } + + if (WARN_ON_ONCE(rate <= 0)) + return -EINVAL; + + return 0; +} + +static const struct clk_ops tegra_cclk_super_ops = { + .get_parent = cclk_super_get_parent, + .set_parent = cclk_super_set_parent, + .set_rate = cclk_super_set_rate, + .recalc_rate = cclk_super_recalc_rate, + .determine_rate = cclk_super_determine_rate, +}; + +static const struct clk_ops tegra_cclk_super_mux_ops = { + .get_parent = cclk_super_get_parent, + .set_parent = cclk_super_set_parent, + .determine_rate = cclk_super_determine_rate, +}; + +struct clk *tegra_clk_register_super_cclk(const char *name, + const char * const *parent_names, u8 num_parents, + unsigned long flags, void __iomem *reg, u8 clk_super_flags, + spinlock_t *lock) +{ + struct tegra_clk_super_mux *super; + struct clk *clk; + struct clk_init_data init; + u32 val; + + if (WARN_ON(cclk_super)) + return ERR_PTR(-EBUSY); + + super = kzalloc(sizeof(*super), GFP_KERNEL); + if (!super) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.flags = flags; + init.parent_names = parent_names; + init.num_parents = num_parents; + + super->reg = reg; + super->lock = lock; + super->width = 4; + super->flags = clk_super_flags; + super->hw.init = &init; + + if (super->flags & TEGRA20_SUPER_CLK) { + init.ops = &tegra_cclk_super_mux_ops; + } else { + init.ops = &tegra_cclk_super_ops; + + super->frac_div.reg = reg + 4; + super->frac_div.shift = 16; + super->frac_div.width = 8; + super->frac_div.frac_width = 1; + super->frac_div.lock = lock; + super->div_ops = &tegra_clk_frac_div_ops; + } + + /* + * Tegra30+ has the following CPUG clock topology: + * + * +---+ +-------+ +-+ +-+ +-+ + * PLLP+->+ +->+DIVIDER+->+0| +-------->+0| ------------->+0| + * | | +-------+ | | | +---+ | | | | | + * PLLC+->+MUX| | +->+ | S | | +->+ | +->+CPU + * ... | | | | | | K | | | | +-------+ | | + * PLLX+->+-->+------------>+1| +->+ I +->+1| +->+ DIV2 +->+1| + * +---+ +++ | P | +++ |SKIPPER| +++ + * ^ | P | ^ +-------+ ^ + * | | E | | | + * PLLX_SEL+--+ | R | | OVERHEAT+--+ + * +---+ | + * | + * SUPER_CDIV_ENB+--+ + * + * Tegra20 is similar, but simpler. It doesn't have the divider and + * thermal DIV2 skipper. + * + * At least for now we're not going to use clock-skipper, hence let's + * ensure that it is disabled. + */ + val = readl_relaxed(reg + 4); + val &= ~SUPER_CDIV_ENB; + writel_relaxed(val, reg + 4); + + clk = clk_register(NULL, &super->hw); + if (IS_ERR(clk)) + kfree(super); + else + cclk_super = super; + + return clk; +} + +int tegra_cclk_pre_pllx_rate_change(void) +{ + if (IS_ERR_OR_NULL(cclk_super)) + return -EINVAL; + + if (cclk_super_get_parent(&cclk_super->hw) == PLLX_INDEX) + cclk_on_pllx = true; + else + cclk_on_pllx = false; + + /* + * CPU needs to be temporarily re-parented away from PLLX if PLLX + * changes its rate. PLLP is a safe parent for CPU on all Tegra SoCs. + */ + if (cclk_on_pllx) + cclk_super_set_parent(&cclk_super->hw, PLLP_INDEX); + + return 0; +} + +void tegra_cclk_post_pllx_rate_change(void) +{ + if (cclk_on_pllx) + cclk_super_set_parent(&cclk_super->hw, PLLX_INDEX); +} |