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path: root/drivers/clk/tegra/clk-tegra-super-cclk.c
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Diffstat (limited to 'drivers/clk/tegra/clk-tegra-super-cclk.c')
-rw-r--r--drivers/clk/tegra/clk-tegra-super-cclk.c212
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);
+}