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path: root/drivers/clk/bcm/clk-iproc-armpll.c
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-rw-r--r--drivers/clk/bcm/clk-iproc-armpll.c282
1 files changed, 282 insertions, 0 deletions
diff --git a/drivers/clk/bcm/clk-iproc-armpll.c b/drivers/clk/bcm/clk-iproc-armpll.c
new file mode 100644
index 000000000..a196ee28a
--- /dev/null
+++ b/drivers/clk/bcm/clk-iproc-armpll.c
@@ -0,0 +1,282 @@
+/*
+ * 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;
+}
+
+/*
+ * 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;
+}
+
+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;
+}
+
+/*
+ * 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;
+}
+
+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);
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-03 06:46:53 +0000