diff options
author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/clk/zynq/pll.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/clk/zynq/pll.c')
-rw-r--r-- | kernel/drivers/clk/zynq/pll.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/kernel/drivers/clk/zynq/pll.c b/kernel/drivers/clk/zynq/pll.c new file mode 100644 index 000000000..00d72fb5c --- /dev/null +++ b/kernel/drivers/clk/zynq/pll.c @@ -0,0 +1,242 @@ +/* + * Zynq PLL driver + * + * Copyright (C) 2013 Xilinx + * + * Sören Brinkmann <soren.brinkmann@xilinx.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License v2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that 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/zynq.h> +#include <linux/clk-provider.h> +#include <linux/slab.h> +#include <linux/io.h> + +/** + * struct zynq_pll + * @hw: Handle between common and hardware-specific interfaces + * @pll_ctrl: PLL control register + * @pll_status: PLL status register + * @lock: Register lock + * @lockbit: Indicates the associated PLL_LOCKED bit in the PLL status + * register. + */ +struct zynq_pll { + struct clk_hw hw; + void __iomem *pll_ctrl; + void __iomem *pll_status; + spinlock_t *lock; + u8 lockbit; +}; +#define to_zynq_pll(_hw) container_of(_hw, struct zynq_pll, hw) + +/* Register bitfield defines */ +#define PLLCTRL_FBDIV_MASK 0x7f000 +#define PLLCTRL_FBDIV_SHIFT 12 +#define PLLCTRL_BPQUAL_MASK (1 << 3) +#define PLLCTRL_PWRDWN_MASK 2 +#define PLLCTRL_PWRDWN_SHIFT 1 +#define PLLCTRL_RESET_MASK 1 +#define PLLCTRL_RESET_SHIFT 0 + +#define PLL_FBDIV_MIN 13 +#define PLL_FBDIV_MAX 66 + +/** + * zynq_pll_round_rate() - Round a clock frequency + * @hw: Handle between common and hardware-specific interfaces + * @rate: Desired clock frequency + * @prate: Clock frequency of parent clock + * Returns frequency closest to @rate the hardware can generate. + */ +static long zynq_pll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + u32 fbdiv; + + fbdiv = DIV_ROUND_CLOSEST(rate, *prate); + if (fbdiv < PLL_FBDIV_MIN) + fbdiv = PLL_FBDIV_MIN; + else if (fbdiv > PLL_FBDIV_MAX) + fbdiv = PLL_FBDIV_MAX; + + return *prate * fbdiv; +} + +/** + * zynq_pll_recalc_rate() - Recalculate clock frequency + * @hw: Handle between common and hardware-specific interfaces + * @parent_rate: Clock frequency of parent clock + * Returns current clock frequency. + */ +static unsigned long zynq_pll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct zynq_pll *clk = to_zynq_pll(hw); + u32 fbdiv; + + /* + * makes probably sense to redundantly save fbdiv in the struct + * zynq_pll to save the IO access. + */ + fbdiv = (clk_readl(clk->pll_ctrl) & PLLCTRL_FBDIV_MASK) >> + PLLCTRL_FBDIV_SHIFT; + + return parent_rate * fbdiv; +} + +/** + * zynq_pll_is_enabled - Check if a clock is enabled + * @hw: Handle between common and hardware-specific interfaces + * Returns 1 if the clock is enabled, 0 otherwise. + * + * Not sure this is a good idea, but since disabled means bypassed for + * this clock implementation we say we are always enabled. + */ +static int zynq_pll_is_enabled(struct clk_hw *hw) +{ + unsigned long flags = 0; + u32 reg; + struct zynq_pll *clk = to_zynq_pll(hw); + + spin_lock_irqsave(clk->lock, flags); + + reg = clk_readl(clk->pll_ctrl); + + spin_unlock_irqrestore(clk->lock, flags); + + return !(reg & (PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK)); +} + +/** + * zynq_pll_enable - Enable clock + * @hw: Handle between common and hardware-specific interfaces + * Returns 0 on success + */ +static int zynq_pll_enable(struct clk_hw *hw) +{ + unsigned long flags = 0; + u32 reg; + struct zynq_pll *clk = to_zynq_pll(hw); + + if (zynq_pll_is_enabled(hw)) + return 0; + + pr_info("PLL: enable\n"); + + /* Power up PLL and wait for lock */ + spin_lock_irqsave(clk->lock, flags); + + reg = clk_readl(clk->pll_ctrl); + reg &= ~(PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK); + clk_writel(reg, clk->pll_ctrl); + while (!(clk_readl(clk->pll_status) & (1 << clk->lockbit))) + ; + + spin_unlock_irqrestore(clk->lock, flags); + + return 0; +} + +/** + * zynq_pll_disable - Disable clock + * @hw: Handle between common and hardware-specific interfaces + * Returns 0 on success + */ +static void zynq_pll_disable(struct clk_hw *hw) +{ + unsigned long flags = 0; + u32 reg; + struct zynq_pll *clk = to_zynq_pll(hw); + + if (!zynq_pll_is_enabled(hw)) + return; + + pr_info("PLL: shutdown\n"); + + /* shut down PLL */ + spin_lock_irqsave(clk->lock, flags); + + reg = clk_readl(clk->pll_ctrl); + reg |= PLLCTRL_RESET_MASK | PLLCTRL_PWRDWN_MASK; + clk_writel(reg, clk->pll_ctrl); + + spin_unlock_irqrestore(clk->lock, flags); +} + +static const struct clk_ops zynq_pll_ops = { + .enable = zynq_pll_enable, + .disable = zynq_pll_disable, + .is_enabled = zynq_pll_is_enabled, + .round_rate = zynq_pll_round_rate, + .recalc_rate = zynq_pll_recalc_rate +}; + +/** + * clk_register_zynq_pll() - Register PLL with the clock framework + * @name PLL name + * @parent Parent clock name + * @pll_ctrl Pointer to PLL control register + * @pll_status Pointer to PLL status register + * @lock_index Bit index to this PLL's lock status bit in @pll_status + * @lock Register lock + * Returns handle to the registered clock. + */ +struct clk *clk_register_zynq_pll(const char *name, const char *parent, + void __iomem *pll_ctrl, void __iomem *pll_status, u8 lock_index, + spinlock_t *lock) +{ + struct zynq_pll *pll; + struct clk *clk; + u32 reg; + const char *parent_arr[1] = {parent}; + unsigned long flags = 0; + struct clk_init_data initd = { + .name = name, + .parent_names = parent_arr, + .ops = &zynq_pll_ops, + .num_parents = 1, + .flags = 0 + }; + + pll = kmalloc(sizeof(*pll), GFP_KERNEL); + if (!pll) + return ERR_PTR(-ENOMEM); + + /* Populate the struct */ + pll->hw.init = &initd; + pll->pll_ctrl = pll_ctrl; + pll->pll_status = pll_status; + pll->lockbit = lock_index; + pll->lock = lock; + + spin_lock_irqsave(pll->lock, flags); + + reg = clk_readl(pll->pll_ctrl); + reg &= ~PLLCTRL_BPQUAL_MASK; + clk_writel(reg, pll->pll_ctrl); + + spin_unlock_irqrestore(pll->lock, flags); + + clk = clk_register(NULL, &pll->hw); + if (WARN_ON(IS_ERR(clk))) + goto free_pll; + + return clk; + +free_pll: + kfree(pll); + + return clk; +} |