clk: rockchip: add reset controller

A patch from »Add real clock support for Rockchip's RK3188« in state Mainline for linux-kernel

From: Heiko Stuebner <heiko@...> Date: Sun, 13 Apr 2014 21:47:19 +0200

Commit-Message

All Rockchip SoCs at least down to the ARM9-based RK28xx include the reset- controller for SoC peripherals in their clock controller. While the older SoCs (ARM9 and Cortex-A8) use a regular scheme to change register values, the Cortex-A9 SoCs use a hiword-mask making locking unecessary. To be compatible with both schemes the reset controller takes a flag to decide which scheme to use. Signed-off-by: Heiko Stuebner <heiko@...>

Patch-Comment

drivers/clk/rockchip/Makefile | 1 + drivers/clk/rockchip/clk.h | 14 +++++ drivers/clk/rockchip/softrst.c | 115 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 130 insertions(+) create mode 100644 drivers/clk/rockchip/softrst.c

Statistics

  • 130 lines added
  • 0 lines removed

Changes

------------------------ drivers/clk/rockchip/Makefile -------------------------
index 7748062..7e4a296 100644
@@ -6,3 +6,4 @@ obj-y += clk-rockchip.o
obj-y += clk.o
obj-y += clk-pll.o
obj-y += clk-cpu.o
+obj-$(CONFIG_RESET_CONTROLLER) += softrst.o
-------------------------- drivers/clk/rockchip/clk.h --------------------------
index 7d1c76c..b52e4c2 100644
@@ -234,4 +234,18 @@ void rockchip_clk_register_armclk(unsigned int lookup_id,
unsigned int num_parents, void __iomem *reg_base,
struct device_node *np);
+#define ROCKCHIP_SOFTRST_HIWORD_MASK BIT(0)
+
+#ifdef CONFIG_RESET_CONTROLLER
+void rockchip_register_softrst(struct device_node *np,
+ unsigned int num_regs,
+ void __iomem *base, u8 flags);
+#else
+static inline void rockchip_register_softrst(struct device_node *np,
+ unsigned int num_regs,
+ void __iomem *base, u8 flags)
+{
+}
+#endif
+
#endif
------------------------ drivers/clk/rockchip/softrst.c ------------------------
new file mode 100644
index 0000000..e981f6c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2014 MundoReader S.L.
+ * Author: Heiko Stuebner <heiko@sntech.de>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+#include "clk.h"
+
+struct rockchip_softrst {
+ struct reset_controller_dev rcdev;
+ void __iomem *reg_base;
+ int num_regs;
+ int num_per_reg;
+ u8 flags;
+ spinlock_t lock;
+};
+
+static int rockchip_softrst_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct rockchip_softrst *softrst = container_of(rcdev,
+ struct rockchip_softrst,
+ rcdev);
+ int bank = id / softrst->num_per_reg;
+ int offset = id % softrst->num_per_reg;
+
+ if (softrst->flags & ROCKCHIP_SOFTRST_HIWORD_MASK) {
+ writel(BIT(offset) | (BIT(offset) << 16),
+ softrst->reg_base + (bank * 4));
+ } else {
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&softrst->lock, flags);
+
+ reg = readl(softrst->reg_base + (bank * 4));
+ writel(reg | BIT(offset), softrst->reg_base + (bank * 4));
+
+ spin_unlock_irqrestore(&softrst->lock, flags);
+ }
+
+ return 0;
+}
+
+static int rockchip_softrst_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct rockchip_softrst *softrst = container_of(rcdev,
+ struct rockchip_softrst,
+ rcdev);
+ int bank = id / BITS_PER_LONG;
+ int offset = id % BITS_PER_LONG;
+
+ if (softrst->flags & ROCKCHIP_SOFTRST_HIWORD_MASK) {
+ writel((BIT(offset) << 16), softrst->reg_base + (bank * 4));
+ } else {
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&softrst->lock, flags);
+
+ reg = readl(softrst->reg_base + (bank * 4));
+ writel(reg & ~BIT(offset), softrst->reg_base + (bank * 4));
+
+ spin_unlock_irqrestore(&softrst->lock, flags);
+ }
+
+ return 0;
+}
+
+static struct reset_control_ops rockchip_softrst_ops = {
+ .assert = rockchip_softrst_assert,
+ .deassert = rockchip_softrst_deassert,
+};
+
+void __init rockchip_register_softrst(struct device_node *np,
+ unsigned int num_regs,
+ void __iomem *base, u8 flags)
+{
+ struct rockchip_softrst *softrst;
+ int ret;
+
+ softrst = kzalloc(sizeof(*softrst), GFP_KERNEL);
+ if (!softrst)
+ return;
+
+ softrst->reg_base = base;
+ softrst->num_regs = num_regs;
+ softrst->num_per_reg = (flags & ROCKCHIP_SOFTRST_HIWORD_MASK) ? 16
+ : 32;
+
+ softrst->rcdev.owner = THIS_MODULE;
+ softrst->rcdev.nr_resets = num_regs * softrst->num_per_reg;
+ softrst->rcdev.ops = &rockchip_softrst_ops;
+ softrst->rcdev.of_node = np;
+ ret = reset_controller_register(&softrst->rcdev);
+ if (ret) {
+ pr_err("%s: could not register reset controller, %d\n",
+ __func__, ret);
+ kfree(softrst);
+ }
+};
 
 

Recent Patches

About Us

Sed lacus. Donec lectus. Nullam pretium nibh ut turpis. Nam bibendum. In nulla tortor, elementum vel, tempor at, varius non, purus. Mauris vitae nisl nec metus placerat consectetuer.

Read More...