diff options
Diffstat (limited to 'drivers/clk/tegra/clk-periph-gate.c')
| -rw-r--r-- | drivers/clk/tegra/clk-periph-gate.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/clk/tegra/clk-periph-gate.c b/drivers/clk/tegra/clk-periph-gate.c new file mode 100644 index 000000000..303ef32ee --- /dev/null +++ b/drivers/clk/tegra/clk-periph-gate.c @@ -0,0 +1,173 @@ +/* + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * + * 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/>. + */ + +#include <linux/clk-provider.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/err.h> + +#include <soc/tegra/fuse.h> + +#include "clk.h" + +static DEFINE_SPINLOCK(periph_ref_lock); + +/* Macros to assist peripheral gate clock */ +#define read_enb(gate) \ + readl_relaxed(gate->clk_base + (gate->regs->enb_reg)) +#define write_enb_set(val, gate) \ + writel_relaxed(val, gate->clk_base + (gate->regs->enb_set_reg)) +#define write_enb_clr(val, gate) \ + writel_relaxed(val, gate->clk_base + (gate->regs->enb_clr_reg)) + +#define read_rst(gate) \ + readl_relaxed(gate->clk_base + (gate->regs->rst_reg)) +#define write_rst_clr(val, gate) \ + writel_relaxed(val, gate->clk_base + (gate->regs->rst_clr_reg)) + +#define periph_clk_to_bit(gate) (1 << (gate->clk_num % 32)) + +#define LVL2_CLK_GATE_OVRE 0x554 + +/* Peripheral gate clock ops */ +static int clk_periph_is_enabled(struct clk_hw *hw) +{ + struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); + int state = 1; + + if (!(read_enb(gate) & periph_clk_to_bit(gate))) + state = 0; + + if (!(gate->flags & TEGRA_PERIPH_NO_RESET)) + if (read_rst(gate) & periph_clk_to_bit(gate)) + state = 0; + + return state; +} + +static int clk_periph_enable(struct clk_hw *hw) +{ + struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); + unsigned long flags = 0; + + spin_lock_irqsave(&periph_ref_lock, flags); + + gate->enable_refcnt[gate->clk_num]++; + if (gate->enable_refcnt[gate->clk_num] > 1) { + spin_unlock_irqrestore(&periph_ref_lock, flags); + return 0; + } + + write_enb_set(periph_clk_to_bit(gate), gate); + udelay(2); + + if (!(gate->flags & TEGRA_PERIPH_NO_RESET) && + !(gate->flags & TEGRA_PERIPH_MANUAL_RESET)) { + if (read_rst(gate) & periph_clk_to_bit(gate)) { + udelay(5); /* reset propogation delay */ + write_rst_clr(periph_clk_to_bit(gate), gate); + } + } + + if (gate->flags & TEGRA_PERIPH_WAR_1005168) { + writel_relaxed(0, gate->clk_base + LVL2_CLK_GATE_OVRE); + writel_relaxed(BIT(22), gate->clk_base + LVL2_CLK_GATE_OVRE); + udelay(1); + writel_relaxed(0, gate->clk_base + LVL2_CLK_GATE_OVRE); + } + + spin_unlock_irqrestore(&periph_ref_lock, flags); + + return 0; +} + +static void clk_periph_disable(struct clk_hw *hw) +{ + struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw); + unsigned long flags = 0; + + spin_lock_irqsave(&periph_ref_lock, flags); + + gate->enable_refcnt[gate->clk_num]--; + if (gate->enable_refcnt[gate->clk_num] > 0) { + spin_unlock_irqrestore(&periph_ref_lock, flags); + return; + } + + /* + * If peripheral is in the APB bus then read the APB bus to + * flush the write operation in apb bus. This will avoid the + * peripheral access after disabling clock + */ + if (gate->flags & TEGRA_PERIPH_ON_APB) + tegra_read_chipid(); + + write_enb_clr(periph_clk_to_bit(gate), gate); + + spin_unlock_irqrestore(&periph_ref_lock, flags); +} + +const struct clk_ops tegra_clk_periph_gate_ops = { + .is_enabled = clk_periph_is_enabled, + .enable = clk_periph_enable, + .disable = clk_periph_disable, +}; + +struct clk *tegra_clk_register_periph_gate(const char *name, + const char *parent_name, u8 gate_flags, void __iomem *clk_base, + unsigned long flags, int clk_num, int *enable_refcnt) +{ + struct tegra_clk_periph_gate *gate; + struct clk *clk; + struct clk_init_data init; + const struct tegra_clk_periph_regs *pregs; + + pregs = get_reg_bank(clk_num); + if (!pregs) + return ERR_PTR(-EINVAL); + + gate = kzalloc(sizeof(*gate), GFP_KERNEL); + if (!gate) { + pr_err("%s: could not allocate periph gate clk\n", __func__); + return ERR_PTR(-ENOMEM); + } + + init.name = name; + init.flags = flags; + init.parent_names = parent_name ? &parent_name : NULL; + init.num_parents = parent_name ? 1 : 0; + init.ops = &tegra_clk_periph_gate_ops; + + gate->magic = TEGRA_CLK_PERIPH_GATE_MAGIC; + gate->clk_base = clk_base; + gate->clk_num = clk_num; + gate->flags = gate_flags; + gate->enable_refcnt = enable_refcnt; + gate->regs = pregs; + + if (read_enb(gate) & periph_clk_to_bit(gate)) + enable_refcnt[clk_num]++; + + /* Data in .init is copied by clk_register(), so stack variable OK */ + gate->hw.init = &init; + + clk = clk_register(NULL, &gate->hw); + if (IS_ERR(clk)) + kfree(gate); + + return clk; +} |