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path: root/drivers/clk/tegra/clk-periph-gate.c
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-rw-r--r--drivers/clk/tegra/clk-periph-gate.c176
1 files changed, 176 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 0000000000..2091fc9b0c
--- /dev/null
+++ b/drivers/clk/tegra/clk-periph-gate.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
+ */
+
+#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 void clk_periph_enable_locked(struct clk_hw *hw)
+{
+ struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw);
+
+ write_enb_set(periph_clk_to_bit(gate), gate);
+ udelay(2);
+
+ 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);
+ }
+}
+
+static void clk_periph_disable_locked(struct clk_hw *hw)
+{
+ struct tegra_clk_periph_gate *gate = to_clk_periph_gate(hw);
+
+ /*
+ * 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);
+}
+
+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);
+
+ if (!gate->enable_refcnt[gate->clk_num]++)
+ clk_periph_enable_locked(hw);
+
+ 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);
+
+ WARN_ON(!gate->enable_refcnt[gate->clk_num]);
+
+ if (--gate->enable_refcnt[gate->clk_num] == 0)
+ clk_periph_disable_locked(hw);
+
+ spin_unlock_irqrestore(&periph_ref_lock, flags);
+}
+
+static void clk_periph_disable_unused(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);
+
+ /*
+ * Some clocks are duplicated and some of them are marked as critical,
+ * like fuse and fuse_burn for example, thus the enable_refcnt will
+ * be non-zero here if the "unused" duplicate is disabled by CCF.
+ */
+ if (!gate->enable_refcnt[gate->clk_num])
+ clk_periph_disable_locked(hw);
+
+ 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,
+ .disable_unused = clk_periph_disable_unused,
+};
+
+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;
+
+ /* 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;
+}