1 files changed, 277 insertions, 0 deletions
diff --git a/drivers/clk/baikal-t1/clk-ccu-pll.c b/drivers/clk/baikal-t1/clk-ccu-pll.c
new file mode 100644
index 000000000..fce02ce77
--- /dev/null
+++ b/drivers/clk/baikal-t1/clk-ccu-pll.c
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *   Dmitry Dunaev <dmitry.dunaev@baikalelectronics.ru>
+ *
+ * Baikal-T1 CCU PLL clocks driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-pll: " fmt
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/ioport.h>
+#include <linux/regmap.h>
+
+#include <dt-bindings/clock/bt1-ccu.h>
+
+#include "ccu-pll.h"
+
+#define CCU_CPU_PLL_BASE		0x000
+#define CCU_SATA_PLL_BASE		0x008
+#define CCU_DDR_PLL_BASE		0x010
+#define CCU_PCIE_PLL_BASE		0x018
+#define CCU_ETH_PLL_BASE		0x020
+
+#define CCU_PLL_INFO(_id, _name, _pname, _base, _flags, _features)	\
+	{								\
+		.id = _id,						\
+		.name = _name,						\
+		.parent_name = _pname,					\
+		.base = _base,						\
+		.flags = _flags,					\
+		.features = _features,					\
+	}
+
+#define CCU_PLL_NUM			ARRAY_SIZE(pll_info)
+
+struct ccu_pll_info {
+	unsigned int id;
+	const char *name;
+	const char *parent_name;
+	unsigned int base;
+	unsigned long flags;
+	unsigned long features;
+};
+
+/*
+ * Alas we have to mark all PLLs as critical. CPU and DDR PLLs are sources of
+ * CPU cores and DDR controller reference clocks, due to which they obviously
+ * shouldn't be ever gated. SATA and PCIe PLLs are the parents of APB-bus and
+ * DDR controller AXI-bus clocks. If they are gated the system will be
+ * unusable. Moreover disabling SATA and Ethernet PLLs causes automatic reset
+ * of the corresponding subsystems. So until we aren't ready to re-initialize
+ * all the devices consuming those PLLs, they will be marked as critical too.
+ */
+static const struct ccu_pll_info pll_info[] = {
+	CCU_PLL_INFO(CCU_CPU_PLL, "cpu_pll", "ref_clk", CCU_CPU_PLL_BASE,
+		     CLK_IS_CRITICAL, CCU_PLL_BASIC),
+	CCU_PLL_INFO(CCU_SATA_PLL, "sata_pll", "ref_clk", CCU_SATA_PLL_BASE,
+		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE, 0),
+	CCU_PLL_INFO(CCU_DDR_PLL, "ddr_pll", "ref_clk", CCU_DDR_PLL_BASE,
+		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE, 0),
+	CCU_PLL_INFO(CCU_PCIE_PLL, "pcie_pll", "ref_clk", CCU_PCIE_PLL_BASE,
+		     CLK_IS_CRITICAL, CCU_PLL_BASIC),
+	CCU_PLL_INFO(CCU_ETH_PLL, "eth_pll", "ref_clk", CCU_ETH_PLL_BASE,
+		     CLK_IS_CRITICAL | CLK_SET_RATE_GATE, 0)
+};
+
+struct ccu_pll_data {
+	struct device_node *np;
+	struct regmap *sys_regs;
+	struct ccu_pll *plls[CCU_PLL_NUM];
+};
+
+static struct ccu_pll_data *pll_data;
+
+static struct ccu_pll *ccu_pll_find_desc(struct ccu_pll_data *data,
+					 unsigned int clk_id)
+{
+	int idx;
+
+	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
+		if (pll_info[idx].id == clk_id)
+			return data->plls[idx];
+	}
+
+	return ERR_PTR(-EINVAL);
+}
+
+static struct ccu_pll_data *ccu_pll_create_data(struct device_node *np)
+{
+	struct ccu_pll_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	data->np = np;
+
+	return data;
+}
+
+static void ccu_pll_free_data(struct ccu_pll_data *data)
+{
+	kfree(data);
+}
+
+static int ccu_pll_find_sys_regs(struct ccu_pll_data *data)
+{
+	data->sys_regs = syscon_node_to_regmap(data->np->parent);
+	if (IS_ERR(data->sys_regs)) {
+		pr_err("Failed to find syscon regs for '%s'\n",
+			of_node_full_name(data->np));
+		return PTR_ERR(data->sys_regs);
+	}
+
+	return 0;
+}
+
+static struct clk_hw *ccu_pll_of_clk_hw_get(struct of_phandle_args *clkspec,
+					    void *priv)
+{
+	struct ccu_pll_data *data = priv;
+	struct ccu_pll *pll;
+	unsigned int clk_id;
+
+	clk_id = clkspec->args[0];
+	pll = ccu_pll_find_desc(data, clk_id);
+	if (IS_ERR(pll)) {
+		if (pll != ERR_PTR(-EPROBE_DEFER))
+			pr_info("Invalid PLL clock ID %d specified\n", clk_id);
+
+		return ERR_CAST(pll);
+	}
+
+	return ccu_pll_get_clk_hw(pll);
+}
+
+static int ccu_pll_clk_register(struct ccu_pll_data *data, bool defer)
+{
+	int idx, ret;
+
+	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
+		const struct ccu_pll_info *info = &pll_info[idx];
+		struct ccu_pll_init_data init = {0};
+
+		/* Defer non-basic PLLs allocation for the probe stage */
+		if (!!(info->features & CCU_PLL_BASIC) ^ defer) {
+			if (!data->plls[idx])
+				data->plls[idx] = ERR_PTR(-EPROBE_DEFER);
+
+			continue;
+		}
+
+		init.id = info->id;
+		init.name = info->name;
+		init.parent_name = info->parent_name;
+		init.base = info->base;
+		init.sys_regs = data->sys_regs;
+		init.np = data->np;
+		init.flags = info->flags;
+		init.features = info->features;
+
+		data->plls[idx] = ccu_pll_hw_register(&init);
+		if (IS_ERR(data->plls[idx])) {
+			ret = PTR_ERR(data->plls[idx]);
+			pr_err("Couldn't register PLL hw '%s'\n",
+				init.name);
+			goto err_hw_unregister;
+		}
+	}
+
+	return 0;
+
+err_hw_unregister:
+	for (--idx; idx >= 0; --idx) {
+		if (!!(pll_info[idx].features & CCU_PLL_BASIC) ^ defer)
+			continue;
+
+		ccu_pll_hw_unregister(data->plls[idx]);
+	}
+
+	return ret;
+}
+
+static void ccu_pll_clk_unregister(struct ccu_pll_data *data, bool defer)
+{
+	int idx;
+
+	/* Uninstall only the clocks registered on the specfied stage */
+	for (idx = 0; idx < CCU_PLL_NUM; ++idx) {
+		if (!!(pll_info[idx].features & CCU_PLL_BASIC) ^ defer)
+			continue;
+
+		ccu_pll_hw_unregister(data->plls[idx]);
+	}
+}
+
+static int ccu_pll_of_register(struct ccu_pll_data *data)
+{
+	int ret;
+
+	ret = of_clk_add_hw_provider(data->np, ccu_pll_of_clk_hw_get, data);
+	if (ret) {
+		pr_err("Couldn't register PLL provider of '%s'\n",
+			of_node_full_name(data->np));
+	}
+
+	return ret;
+}
+
+static int ccu_pll_probe(struct platform_device *pdev)
+{
+	struct ccu_pll_data *data = pll_data;
+
+	if (!data)
+		return -EINVAL;
+
+	return ccu_pll_clk_register(data, false);
+}
+
+static const struct of_device_id ccu_pll_of_match[] = {
+	{ .compatible = "baikal,bt1-ccu-pll" },
+	{ }
+};
+
+static struct platform_driver ccu_pll_driver = {
+	.probe  = ccu_pll_probe,
+	.driver = {
+		.name = "clk-ccu-pll",
+		.of_match_table = ccu_pll_of_match,
+		.suppress_bind_attrs = true,
+	},
+};
+builtin_platform_driver(ccu_pll_driver);
+
+static __init void ccu_pll_init(struct device_node *np)
+{
+	struct ccu_pll_data *data;
+	int ret;
+
+	data = ccu_pll_create_data(np);
+	if (IS_ERR(data))
+		return;
+
+	ret = ccu_pll_find_sys_regs(data);
+	if (ret)
+		goto err_free_data;
+
+	ret = ccu_pll_clk_register(data, true);
+	if (ret)
+		goto err_free_data;
+
+	ret = ccu_pll_of_register(data);
+	if (ret)
+		goto err_clk_unregister;
+
+	pll_data = data;
+
+	return;
+
+err_clk_unregister:
+	ccu_pll_clk_unregister(data, true);
+
+err_free_data:
+	ccu_pll_free_data(data);
+}
+CLK_OF_DECLARE_DRIVER(ccu_pll, "baikal,bt1-ccu-pll", ccu_pll_init);