[PATCH V7 2/7] clk: imx: add scu clock common part

[aisheng.dong@nxp.com (A.s. Dong)]

Add scu clock common part which will be used by client clock drivers.
SCU clocks are totally different from the legacy clocks (No much
legacy things can be reused). So a new configuration option
CONFIG_MXC_CLK_SCU is added.

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
ChangeLog:
v5->v6:
 * simply the whole clock driver a lot by re-orgnizing the driver into a
   few clock types:: scu clock (merge scu divider/gate/mux) and scu gpr lock
   which accessing is through SCU protocol and LPCG clock which is directly
   accessible by CPU.
 * LPCG clock support will be added in next patch, gpr clock is still not used
   and will be added later.
 * remove old year license as the code is totally rewritten
 * scu mux support will be added later as it's also still not used.
v4->v5:
 * add more explanation in commit message on why put scu clocks
in a deeper folder.
 * move scu clk files into the top directory of imx folder
v3->v4:
 * scu headfile path change
v2->v3:
 * no changes
v1->v2:
 * update function call name
---
 drivers/clk/imx/Kconfig   |   4 +
 drivers/clk/imx/Makefile  |   3 +
 drivers/clk/imx/clk-scu.c | 237 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/imx/clk-scu.h |  21 ++++
 4 files changed, 265 insertions(+)
 create mode 100644 drivers/clk/imx/clk-scu.c
 create mode 100644 drivers/clk/imx/clk-scu.h

diff --git a/drivers/clk/imx/Kconfig b/drivers/clk/imx/Kconfig
index 43a3ecc..63e7b01 100644
--- a/drivers/clk/imx/Kconfig
+++ b/drivers/clk/imx/Kconfig
@@ -3,3 +3,7 @@
 config MXC_CLK
 	bool
 	depends on ARCH_MXC
+
+config MXC_CLK_SCU
+	bool
+	depends on ARCH_MXC && ARM64
diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index d447f8c..eec6d72 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -13,6 +13,9 @@ obj-$(CONFIG_MXC_CLK) += \
 	clk-pllv3.o \
 	clk-pfd.o
 
+obj-$(CONFIG_MXC_CLK_SCU) += \
+	clk-scu.o
+
 obj-$(CONFIG_SOC_IMX1)   += clk-imx1.o
 obj-$(CONFIG_SOC_IMX21)  += clk-imx21.o
 obj-$(CONFIG_SOC_IMX25)  += clk-imx25.o
diff --git a/drivers/clk/imx/clk-scu.c b/drivers/clk/imx/clk-scu.c
new file mode 100644
index 0000000..9fec574
--- /dev/null
+++ b/drivers/clk/imx/clk-scu.c
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 NXP
+ *   Dong Aisheng <aisheng.dong@nxp.com>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+#include "clk-scu.h"
+
+struct imx_sc_ipc *ccm_ipc_handle;
+
+struct clk_scu {
+	struct clk_hw hw;
+	u32 rsrc_id;
+	u8 clk_type;
+};
+
+/* SCU Clock Protocol definitions */
+
+/* rate */
+struct imx_sc_msg_req_set_clock_rate {
+	struct imx_sc_rpc_msg hdr;
+	u32 rate;
+	u16 resource;
+	u8 clk;
+} __packed;
+
+struct req_get_clock_rate {
+	u16 resource;
+	u8 clk;
+} __packed;
+
+struct resp_get_clock_rate {
+	u32 rate;
+};
+
+struct imx_sc_msg_get_clock_rate {
+	struct imx_sc_rpc_msg hdr;
+	union {
+		struct req_get_clock_rate req;
+		struct resp_get_clock_rate resp;
+	} data;
+} __packed;
+
+/* gate */
+struct imx_sc_msg_req_clock_enable {
+	struct imx_sc_rpc_msg hdr;
+	u16 resource;
+	u8 clk;
+	u8 enable;
+	u8 autog;
+} __packed;
+
+static inline struct clk_scu *to_clk_scu(struct clk_hw *hw)
+{
+	return container_of(hw, struct clk_scu, hw);
+}
+
+/*
+ * clk_scu_recalc_rate - Get clock rate for a SCU clock
+ * @hw: clock to get rate for
+ * @parent_rate: parent rate provided by common clock framework, not used
+ *
+ * Gets the current clock rate of a SCU clock. Returns the current
+ * clock rate, or zero in failure.
+ */
+static unsigned long clk_scu_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	struct clk_scu *clk = to_clk_scu(hw);
+	struct imx_sc_msg_get_clock_rate msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	int ret;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_PM;
+	hdr->func = IMX_SC_PM_FUNC_GET_CLOCK_RATE;
+	hdr->size = 2;
+
+	msg.data.req.resource = clk->rsrc_id;
+	msg.data.req.clk = clk->clk_type;
+
+	ret = imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
+	if (ret) {
+		pr_err("%s: failed to get clock rate %d\n",
+			clk_hw_get_name(hw), ret);
+		return 0;
+	}
+
+	return msg.data.resp.rate;
+}
+
+/*
+ * clk_scu_round_rate - Round clock rate for a SCU clock
+ * @hw: clock to round rate for
+ * @rate: rate to round
+ * @parent_rate: parent rate provided by common clock framework, not used
+ *
+ * Gets the current clock rate of a SCU clock. Returns the current
+ * clock rate, or zero in failure.
+ */
+static long clk_scu_round_rate(struct clk_hw *hw, unsigned long rate,
+				       unsigned long *parent_rate)
+{
+	/*
+	 * Assume we support all the requested rate and let the SCU firmware
+	 * to handle the left work
+	 */
+	return rate;
+}
+
+/*
+ * clk_scu_set_rate - Set rate for a SCU clock
+ * @hw: clock to change rate for
+ * @rate: target rate for the clock
+ * @parent_rate: rate of the clock parent, not used for SCU clocks
+ *
+ * Sets a clock frequency for a SCU clock. Returns the SCU
+ * protocol status.
+ */
+static int clk_scu_set_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long parent_rate)
+{
+	struct clk_scu *clk = to_clk_scu(hw);
+	struct imx_sc_msg_req_set_clock_rate msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_PM;
+	hdr->func = IMX_SC_PM_FUNC_SET_CLOCK_RATE;
+	hdr->size = 3;
+
+	msg.rate = rate;
+	msg.resource = clk->rsrc_id;
+	msg.clk = clk->clk_type;
+
+	return imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
+}
+
+static int sc_pm_clock_enable(struct imx_sc_ipc *ipc, u32 resource,
+				   u8 clk, bool enable, bool autog)
+{
+	struct imx_sc_msg_req_clock_enable msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_PM;
+	hdr->func = IMX_SC_PM_FUNC_CLOCK_ENABLE;
+	hdr->size = 3;
+
+	msg.resource = resource;
+	msg.clk = clk;
+	msg.enable = enable;
+	msg.autog = autog;
+
+	return imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
+}
+
+/*
+ * clk_scu_prepare - Enable a SCU clock
+ * @hw: clock to enable
+ *
+ * Enable the clock at the DSC slice level
+ */
+static int clk_scu_prepare(struct clk_hw *hw)
+{
+	struct clk_scu *clk = to_clk_scu(hw);
+
+	return sc_pm_clock_enable(ccm_ipc_handle, clk->rsrc_id,
+				  clk->clk_type, true, false);
+}
+
+/*
+ * clk_scu_unprepare - Disable a SCU clock
+ * @hw: clock to enable
+ *
+ * Disable the clock at the DSC slice level
+ */
+static void clk_scu_unprepare(struct clk_hw *hw)
+{
+	struct clk_scu *clk = to_clk_scu(hw);
+	int ret;
+
+	ret = sc_pm_clock_enable(ccm_ipc_handle, clk->rsrc_id,
+				 clk->clk_type, false, false);
+	if (ret)
+		pr_warn("%s: clk unprepare failed %d\n", clk_hw_get_name(hw),
+			ret);
+}
+
+static const struct clk_ops clk_scu_ops = {
+	.recalc_rate = clk_scu_recalc_rate,
+	.round_rate = clk_scu_round_rate,
+	.set_rate = clk_scu_set_rate,
+	.prepare = clk_scu_prepare,
+	.unprepare = clk_scu_unprepare,
+};
+
+struct clk_hw *imx_clk_scu(const char *name, u32 rsrc_id, u8 clk_type)
+{
+	struct clk_init_data init;
+	struct clk_scu *clk;
+	struct clk_hw *hw;
+	int ret;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	clk->rsrc_id = rsrc_id;
+	clk->clk_type = clk_type;
+
+	init.name = name;
+	init.ops = &clk_scu_ops;
+	init.num_parents = 0;
+	/*
+	 * Note on MX8, the clocks are tightly coupled with power domain
+	 * that once the power domain is off, the clock status may be
+	 * lost. So we make it NOCACHE to let user to retrieve the real
+	 * clock status from HW instead of using the possible invalid
+	 * cached rate.
+	 */
+	init.flags = CLK_GET_RATE_NOCACHE;
+	clk->hw.init = &init;
+
+	hw = &clk->hw;
+	ret = clk_hw_register(NULL, hw);
+	if (ret) {
+		kfree(clk);
+		hw = ERR_PTR(ret);
+	}
+
+	return hw;
+}
diff --git a/drivers/clk/imx/clk-scu.h b/drivers/clk/imx/clk-scu.h
new file mode 100644
index 0000000..09f381b
--- /dev/null
+++ b/drivers/clk/imx/clk-scu.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2018 NXP
+ *   Dong Aisheng <aisheng.dong@nxp.com>
+ */
+
+#ifndef __IMX_CLK_SCU_H
+#define __IMX_CLK_SCU_H
+
+#include <linux/firmware/imx/sci.h>
+
+extern struct imx_sc_ipc *ccm_ipc_handle;
+
+static inline int imx_clk_scu_init(void)
+{
+	return imx_scu_get_handle(&ccm_ipc_handle);
+}
+
+struct clk_hw *imx_clk_scu(const char *name, u32 rsrc_id, u8 clk_type);
+
+#endif
-- 
2.7.4