Release 4.7 drivers/clk/bcm/clk-iproc-armpll.c
/*
* Copyright (C) 2014 Broadcom Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/clkdev.h>
#include <linux/of_address.h>
#define IPROC_CLK_MAX_FREQ_POLICY 0x3
#define IPROC_CLK_POLICY_FREQ_OFFSET 0x008
#define IPROC_CLK_POLICY_FREQ_POLICY_FREQ_SHIFT 8
#define IPROC_CLK_POLICY_FREQ_POLICY_FREQ_MASK 0x7
#define IPROC_CLK_PLLARMA_OFFSET 0xc00
#define IPROC_CLK_PLLARMA_LOCK_SHIFT 28
#define IPROC_CLK_PLLARMA_PDIV_SHIFT 24
#define IPROC_CLK_PLLARMA_PDIV_MASK 0xf
#define IPROC_CLK_PLLARMA_NDIV_INT_SHIFT 8
#define IPROC_CLK_PLLARMA_NDIV_INT_MASK 0x3ff
#define IPROC_CLK_PLLARMB_OFFSET 0xc04
#define IPROC_CLK_PLLARMB_NDIV_FRAC_MASK 0xfffff
#define IPROC_CLK_PLLARMC_OFFSET 0xc08
#define IPROC_CLK_PLLARMC_BYPCLK_EN_SHIFT 8
#define IPROC_CLK_PLLARMC_MDIV_MASK 0xff
#define IPROC_CLK_PLLARMCTL5_OFFSET 0xc20
#define IPROC_CLK_PLLARMCTL5_H_MDIV_MASK 0xff
#define IPROC_CLK_PLLARM_OFFSET_OFFSET 0xc24
#define IPROC_CLK_PLLARM_SW_CTL_SHIFT 29
#define IPROC_CLK_PLLARM_NDIV_INT_OFFSET_SHIFT 20
#define IPROC_CLK_PLLARM_NDIV_INT_OFFSET_MASK 0xff
#define IPROC_CLK_PLLARM_NDIV_FRAC_OFFSET_MASK 0xfffff
#define IPROC_CLK_ARM_DIV_OFFSET 0xe00
#define IPROC_CLK_ARM_DIV_PLL_SELECT_OVERRIDE_SHIFT 4
#define IPROC_CLK_ARM_DIV_ARM_PLL_SELECT_MASK 0xf
#define IPROC_CLK_POLICY_DBG_OFFSET 0xec0
#define IPROC_CLK_POLICY_DBG_ACT_FREQ_SHIFT 12
#define IPROC_CLK_POLICY_DBG_ACT_FREQ_MASK 0x7
enum iproc_arm_pll_fid {
ARM_PLL_FID_CRYSTAL_CLK = 0,
ARM_PLL_FID_SYS_CLK = 2,
ARM_PLL_FID_CH0_SLOW_CLK = 6,
ARM_PLL_FID_CH1_FAST_CLK = 7
};
struct iproc_arm_pll {
struct clk_hw hw;
void __iomem *base;
unsigned long rate;
};
#define to_iproc_arm_pll(hw) container_of(hw, struct iproc_arm_pll, hw)
static unsigned int __get_fid(struct iproc_arm_pll *pll)
{
u32 val;
unsigned int policy, fid, active_fid;
val = readl(pll->base + IPROC_CLK_ARM_DIV_OFFSET);
if (val & (1 << IPROC_CLK_ARM_DIV_PLL_SELECT_OVERRIDE_SHIFT))
policy = val & IPROC_CLK_ARM_DIV_ARM_PLL_SELECT_MASK;
else
policy = 0;
/* something is seriously wrong */
BUG_ON(policy > IPROC_CLK_MAX_FREQ_POLICY);
val = readl(pll->base + IPROC_CLK_POLICY_FREQ_OFFSET);
fid = (val >> (IPROC_CLK_POLICY_FREQ_POLICY_FREQ_SHIFT * policy)) &
IPROC_CLK_POLICY_FREQ_POLICY_FREQ_MASK;
val = readl(pll->base + IPROC_CLK_POLICY_DBG_OFFSET);
active_fid = IPROC_CLK_POLICY_DBG_ACT_FREQ_MASK &
(val >> IPROC_CLK_POLICY_DBG_ACT_FREQ_SHIFT);
if (fid != active_fid) {
pr_debug("%s: fid override %u->%u\n", __func__, fid,
active_fid);
fid = active_fid;
}
pr_debug("%s: active fid: %u\n", __func__, fid);
return fid;
}
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/*
* Determine the mdiv (post divider) based on the frequency ID being used.
* There are 4 sources that can be used to derive the output clock rate:
* - 25 MHz Crystal
* - System clock
* - PLL channel 0 (slow clock)
* - PLL channel 1 (fast clock)
*/
static int __get_mdiv(struct iproc_arm_pll *pll)
{
unsigned int fid;
int mdiv;
u32 val;
fid = __get_fid(pll);
switch (fid) {
case ARM_PLL_FID_CRYSTAL_CLK:
case ARM_PLL_FID_SYS_CLK:
mdiv = 1;
break;
case ARM_PLL_FID_CH0_SLOW_CLK:
val = readl(pll->base + IPROC_CLK_PLLARMC_OFFSET);
mdiv = val & IPROC_CLK_PLLARMC_MDIV_MASK;
if (mdiv == 0)
mdiv = 256;
break;
case ARM_PLL_FID_CH1_FAST_CLK:
val = readl(pll->base + IPROC_CLK_PLLARMCTL5_OFFSET);
mdiv = val & IPROC_CLK_PLLARMCTL5_H_MDIV_MASK;
if (mdiv == 0)
mdiv = 256;
break;
default:
mdiv = -EFAULT;
}
return mdiv;
}
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static unsigned int __get_ndiv(struct iproc_arm_pll *pll)
{
u32 val;
unsigned int ndiv_int, ndiv_frac, ndiv;
val = readl(pll->base + IPROC_CLK_PLLARM_OFFSET_OFFSET);
if (val & (1 << IPROC_CLK_PLLARM_SW_CTL_SHIFT)) {
/*
* offset mode is active. Read the ndiv from the PLLARM OFFSET
* register
*/
ndiv_int = (val >> IPROC_CLK_PLLARM_NDIV_INT_OFFSET_SHIFT) &
IPROC_CLK_PLLARM_NDIV_INT_OFFSET_MASK;
if (ndiv_int == 0)
ndiv_int = 256;
ndiv_frac = val & IPROC_CLK_PLLARM_NDIV_FRAC_OFFSET_MASK;
} else {
/* offset mode not active */
val = readl(pll->base + IPROC_CLK_PLLARMA_OFFSET);
ndiv_int = (val >> IPROC_CLK_PLLARMA_NDIV_INT_SHIFT) &
IPROC_CLK_PLLARMA_NDIV_INT_MASK;
if (ndiv_int == 0)
ndiv_int = 1024;
val = readl(pll->base + IPROC_CLK_PLLARMB_OFFSET);
ndiv_frac = val & IPROC_CLK_PLLARMB_NDIV_FRAC_MASK;
}
ndiv = (ndiv_int << 20) | ndiv_frac;
return ndiv;
}
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/*
* The output frequency of the ARM PLL is calculated based on the ARM PLL
* divider values:
* pdiv = ARM PLL pre-divider
* ndiv = ARM PLL multiplier
* mdiv = ARM PLL post divider
*
* The frequency is calculated by:
* ((ndiv * parent clock rate) / pdiv) / mdiv
*/
static unsigned long iproc_arm_pll_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct iproc_arm_pll *pll = to_iproc_arm_pll(hw);
u32 val;
int mdiv;
u64 ndiv;
unsigned int pdiv;
/* in bypass mode, use parent rate */
val = readl(pll->base + IPROC_CLK_PLLARMC_OFFSET);
if (val & (1 << IPROC_CLK_PLLARMC_BYPCLK_EN_SHIFT)) {
pll->rate = parent_rate;
return pll->rate;
}
/* PLL needs to be locked */
val = readl(pll->base + IPROC_CLK_PLLARMA_OFFSET);
if (!(val & (1 << IPROC_CLK_PLLARMA_LOCK_SHIFT))) {
pll->rate = 0;
return 0;
}
pdiv = (val >> IPROC_CLK_PLLARMA_PDIV_SHIFT) &
IPROC_CLK_PLLARMA_PDIV_MASK;
if (pdiv == 0)
pdiv = 16;
ndiv = __get_ndiv(pll);
mdiv = __get_mdiv(pll);
if (mdiv <= 0) {
pll->rate = 0;
return 0;
}
pll->rate = (ndiv * parent_rate) >> 20;
pll->rate = (pll->rate / pdiv) / mdiv;
pr_debug("%s: ARM PLL rate: %lu. parent rate: %lu\n", __func__,
pll->rate, parent_rate);
pr_debug("%s: ndiv_int: %u, pdiv: %u, mdiv: %d\n", __func__,
(unsigned int)(ndiv >> 20), pdiv, mdiv);
return pll->rate;
}
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static const struct clk_ops iproc_arm_pll_ops = {
.recalc_rate = iproc_arm_pll_recalc_rate,
};
void __init iproc_armpll_setup(struct device_node *node)
{
int ret;
struct clk *clk;
struct iproc_arm_pll *pll;
struct clk_init_data init;
const char *parent_name;
pll = kzalloc(sizeof(*pll), GFP_KERNEL);
if (WARN_ON(!pll))
return;
pll->base = of_iomap(node, 0);
if (WARN_ON(!pll->base))
goto err_free_pll;
init.name = node->name;
init.ops = &iproc_arm_pll_ops;
init.flags = 0;
parent_name = of_clk_get_parent_name(node, 0);
init.parent_names = (parent_name ? &parent_name : NULL);
init.num_parents = (parent_name ? 1 : 0);
pll->hw.init = &init;
clk = clk_register(NULL, &pll->hw);
if (WARN_ON(IS_ERR(clk)))
goto err_iounmap;
ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
if (WARN_ON(ret))
goto err_clk_unregister;
return;
err_clk_unregister:
clk_unregister(clk);
err_iounmap:
iounmap(pll->base);
err_free_pll:
kfree(pll);
}
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