ASoC: Intel: Skylake: Add ssp clock driver

For certain platforms, it is required to start the clocks (mclk/sclk/fs)
before the stream start. Example: for few chrome systems, codec needs the
mclk/sclk to be enabled early for a successful clock synchronization and
for few IVI platforms, clock need to be enabled at boot and should be ON
always.

Add the required structures and create set_dma_control ipc to enable or
disable the clock. To enable sclk without fs, mclk ipc structure is used,
else sclkfs ipc structure is used.

Clock prepare/unprepare are used to enable/disable the clock as the IPC
will be sent in non-atomic context. The clk set_dma_control IPC
structures are populated during the set_rate callback and IPC is sent
to enable the clock during prepare callback.

This patch creates virtual clock driver, which allows the machine driver
to use the clock interface to send IPCs to DSP to enable/disable the
clocks.
Signed-off-by: Sriram Periyasamy <sriramx.periyasamy@intel.com>
Signed-off-by: Jaikrishna Nemallapudi <jaikrishnax.nemallapudi@intel.com>
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/Kconfig

@@ -97,6 +97,9 @@ config SND_SST_ATOM_HIFI2_PLATFORM
 	  codec, then enable this option by saying Y or m. This is a
 	  recommended option
 
+config SND_SOC_INTEL_SKYLAKE_SSP_CLK
+	tristate
+
 config SND_SOC_INTEL_SKYLAKE
 	tristate "SKL/BXT/KBL/GLK/CNL... Platforms"
 	depends on PCI && ACPI

sound/soc/intel/skylake/Makefile

@@ -14,3 +14,8 @@ snd-soc-skl-ipc-objs := skl-sst-ipc.o skl-sst-dsp.o cnl-sst-dsp.o \
 		skl-sst-utils.o
 
 obj-$(CONFIG_SND_SOC_INTEL_SKYLAKE) += snd-soc-skl-ipc.o
+
+#Skylake Clock device support
+snd-soc-skl-ssp-clk-objs := skl-ssp-clk.o
+
+obj-$(CONFIG_SND_SOC_INTEL_SKYLAKE_SSP_CLK) += snd-soc-skl-ssp-clk.o

sound/soc/intel/skylake/skl-messages.c

@@ -675,6 +675,7 @@ int skl_dsp_set_dma_control(struct skl_sst *ctx, u32 *caps,
 	kfree(dma_ctrl);
 	return err;
 }
+EXPORT_SYMBOL_GPL(skl_dsp_set_dma_control);
 
 static void skl_setup_out_format(struct skl_sst *ctx,
 			struct skl_module_cfg *mconfig,

sound/soc/intel/skylake/skl-ssp-clk.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright(c) 2015-17 Intel Corporation
+
+/*
+ *  skl-ssp-clk.c - ASoC skylake ssp clock driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include "skl.h"
+#include "skl-ssp-clk.h"
+#include "skl-topology.h"
+
+#define to_skl_clk(_hw)	container_of(_hw, struct skl_clk, hw)
+
+struct skl_clk_parent {
+	struct clk_hw *hw;
+	struct clk_lookup *lookup;
+};
+
+struct skl_clk {
+	struct clk_hw hw;
+	struct clk_lookup *lookup;
+	unsigned long rate;
+	struct skl_clk_pdata *pdata;
+	u32 id;
+};
+
+struct skl_clk_data {
+	struct skl_clk_parent parent[SKL_MAX_CLK_SRC];
+	struct skl_clk *clk[SKL_MAX_CLK_CNT];
+	u8 avail_clk_cnt;
+};
+
+static int skl_get_clk_type(u32 index)
+{
+	switch (index) {
+	case 0 ... (SKL_SCLK_OFS - 1):
+		return SKL_MCLK;
+
+	case SKL_SCLK_OFS ... (SKL_SCLKFS_OFS - 1):
+		return SKL_SCLK;
+
+	case SKL_SCLKFS_OFS ... (SKL_MAX_CLK_CNT - 1):
+		return SKL_SCLK_FS;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int skl_get_vbus_id(u32 index, u8 clk_type)
+{
+	switch (clk_type) {
+	case SKL_MCLK:
+		return index;
+
+	case SKL_SCLK:
+		return index - SKL_SCLK_OFS;
+
+	case SKL_SCLK_FS:
+		return index - SKL_SCLKFS_OFS;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static void skl_fill_clk_ipc(struct skl_clk_rate_cfg_table *rcfg, u8 clk_type)
+{
+	struct nhlt_fmt_cfg *fmt_cfg;
+	union skl_clk_ctrl_ipc *ipc;
+	struct wav_fmt *wfmt;
+
+	if (!rcfg)
+		return;
+
+	ipc = &rcfg->dma_ctl_ipc;
+	if (clk_type == SKL_SCLK_FS) {
+		fmt_cfg = (struct nhlt_fmt_cfg *)rcfg->config;
+		wfmt = &fmt_cfg->fmt_ext.fmt;
+
+		/* Remove TLV Header size */
+		ipc->sclk_fs.hdr.size = sizeof(struct skl_dmactrl_sclkfs_cfg) -
+						sizeof(struct skl_tlv_hdr);
+		ipc->sclk_fs.sampling_frequency = wfmt->samples_per_sec;
+		ipc->sclk_fs.bit_depth = wfmt->bits_per_sample;
+		ipc->sclk_fs.valid_bit_depth =
+			fmt_cfg->fmt_ext.sample.valid_bits_per_sample;
+		ipc->sclk_fs.number_of_channels = wfmt->channels;
+	} else {
+		ipc->mclk.hdr.type = DMA_CLK_CONTROLS;
+		/* Remove TLV Header size */
+		ipc->mclk.hdr.size = sizeof(struct skl_dmactrl_mclk_cfg) -
+						sizeof(struct skl_tlv_hdr);
+	}
+}
+
+/* Sends dma control IPC to turn the clock ON/OFF */
+static int skl_send_clk_dma_control(struct skl *skl,
+				struct skl_clk_rate_cfg_table *rcfg,
+				u32 vbus_id, u8 clk_type,
+				bool enable)
+{
+	struct nhlt_specific_cfg *sp_cfg;
+	u32 i2s_config_size, node_id = 0;
+	struct nhlt_fmt_cfg *fmt_cfg;
+	union skl_clk_ctrl_ipc *ipc;
+	void *i2s_config = NULL;
+	u8 *data, size;
+	int ret;
+
+	if (!rcfg)
+		return -EIO;
+
+	ipc = &rcfg->dma_ctl_ipc;
+	fmt_cfg = (struct nhlt_fmt_cfg *)rcfg->config;
+	sp_cfg = &fmt_cfg->config;
+
+	if (clk_type == SKL_SCLK_FS) {
+		ipc->sclk_fs.hdr.type =
+			enable ? DMA_TRANSMITION_START : DMA_TRANSMITION_STOP;
+		data = (u8 *)&ipc->sclk_fs;
+		size = sizeof(struct skl_dmactrl_sclkfs_cfg);
+	} else {
+		/* 1 to enable mclk, 0 to enable sclk */
+		if (clk_type == SKL_SCLK)
+			ipc->mclk.mclk = 0;
+		else
+			ipc->mclk.mclk = 1;
+
+		ipc->mclk.keep_running = enable;
+		ipc->mclk.warm_up_over = enable;
+		ipc->mclk.clk_stop_over = !enable;
+		data = (u8 *)&ipc->mclk;
+		size = sizeof(struct skl_dmactrl_mclk_cfg);
+	}
+
+	i2s_config_size = sp_cfg->size + size;
+	i2s_config = kzalloc(i2s_config_size, GFP_KERNEL);
+	if (!i2s_config)
+		return -ENOMEM;
+
+	/* copy blob */
+	memcpy(i2s_config, sp_cfg->caps, sp_cfg->size);
+
+	/* copy additional dma controls information */
+	memcpy(i2s_config + sp_cfg->size, data, size);
+
+	node_id = ((SKL_DMA_I2S_LINK_INPUT_CLASS << 8) | (vbus_id << 4));
+	ret = skl_dsp_set_dma_control(skl->skl_sst, (u32 *)i2s_config,
+					i2s_config_size, node_id);
+	kfree(i2s_config);
+
+	return ret;
+}
+
+static struct skl_clk_rate_cfg_table *skl_get_rate_cfg(
+		struct skl_clk_rate_cfg_table *rcfg,
+				unsigned long rate)
+{
+	int i;
+
+	for (i = 0; (i < SKL_MAX_CLK_RATES) && rcfg[i].rate; i++) {
+		if (rcfg[i].rate == rate)
+			return &rcfg[i];
+	}
+
+	return NULL;
+}
+
+static int skl_clk_change_status(struct skl_clk *clkdev,
+				bool enable)
+{
+	struct skl_clk_rate_cfg_table *rcfg;
+	int vbus_id, clk_type;
+
+	clk_type = skl_get_clk_type(clkdev->id);
+	if (clk_type < 0)
+		return clk_type;
+
+	vbus_id = skl_get_vbus_id(clkdev->id, clk_type);
+	if (vbus_id < 0)
+		return vbus_id;
+
+	rcfg = skl_get_rate_cfg(clkdev->pdata->ssp_clks[clkdev->id].rate_cfg,
+						clkdev->rate);
+	if (!rcfg)
+		return -EINVAL;
+
+	return skl_send_clk_dma_control(clkdev->pdata->pvt_data, rcfg,
+					vbus_id, clk_type, enable);
+}
+
+static int skl_clk_prepare(struct clk_hw *hw)
+{
+	struct skl_clk *clkdev = to_skl_clk(hw);
+
+	return skl_clk_change_status(clkdev, true);
+}
+
+static void skl_clk_unprepare(struct clk_hw *hw)
+{
+	struct skl_clk *clkdev = to_skl_clk(hw);
+
+	skl_clk_change_status(clkdev, false);
+}
+
+static int skl_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long parent_rate)
+{
+	struct skl_clk *clkdev = to_skl_clk(hw);
+	struct skl_clk_rate_cfg_table *rcfg;
+	int clk_type;
+
+	if (!rate)
+		return -EINVAL;
+
+	rcfg = skl_get_rate_cfg(clkdev->pdata->ssp_clks[clkdev->id].rate_cfg,
+							rate);
+	if (!rcfg)
+		return -EINVAL;
+
+	clk_type = skl_get_clk_type(clkdev->id);
+	if (clk_type < 0)
+		return clk_type;
+
+	skl_fill_clk_ipc(rcfg, clk_type);
+	clkdev->rate = rate;
+
+	return 0;
+}
+
+static unsigned long skl_clk_recalc_rate(struct clk_hw *hw,
+				unsigned long parent_rate)
+{
+	struct skl_clk *clkdev = to_skl_clk(hw);
+
+	if (clkdev->rate)
+		return clkdev->rate;
+
+	return 0;
+}
+
+/* Not supported by clk driver. Implemented to satisfy clk fw */
+long skl_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *parent_rate)
+{
+	return rate;
+}
+
+/*
+ * prepare/unprepare are used instead of enable/disable as IPC will be sent
+ * in non-atomic context.
+ */
+static const struct clk_ops skl_clk_ops = {
+	.prepare = skl_clk_prepare,
+	.unprepare = skl_clk_unprepare,
+	.set_rate = skl_clk_set_rate,
+	.round_rate = skl_clk_round_rate,
+	.recalc_rate = skl_clk_recalc_rate,
+};
+
+static void unregister_parent_src_clk(struct skl_clk_parent *pclk,
+					unsigned int id)
+{
+	while (id--) {
+		clkdev_drop(pclk[id].lookup);
+		clk_hw_unregister_fixed_rate(pclk[id].hw);
+	}
+}
+
+static void unregister_src_clk(struct skl_clk_data *dclk)
+{
+	u8 cnt = dclk->avail_clk_cnt;
+
+	while (cnt--)
+		clkdev_drop(dclk->clk[cnt]->lookup);
+}
+
+static int skl_register_parent_clks(struct device *dev,
+			struct skl_clk_parent *parent,
+			struct skl_clk_parent_src *pclk)
+{
+	int i, ret;
+
+	for (i = 0; i < SKL_MAX_CLK_SRC; i++) {
+
+		/* Register Parent clock */
+		parent[i].hw = clk_hw_register_fixed_rate(dev, pclk[i].name,
+				pclk[i].parent_name, 0, pclk[i].rate);
+		if (IS_ERR(parent[i].hw)) {
+			ret = PTR_ERR(parent[i].hw);
+			goto err;
+		}
+
+		parent[i].lookup = clkdev_hw_create(parent[i].hw, pclk[i].name,
+									NULL);
+		if (!parent[i].lookup) {
+			clk_hw_unregister_fixed_rate(parent[i].hw);
+			ret = -ENOMEM;
+			goto err;
+		}
+	}
+
+	return 0;
+err:
+	unregister_parent_src_clk(parent, i);
+	return ret;
+}
+
+/* Assign fmt_config to clk_data */
+static struct skl_clk *register_skl_clk(struct device *dev,
+			struct skl_ssp_clk *clk,
+			struct skl_clk_pdata *clk_pdata, int id)
+{
+	struct clk_init_data init;
+	struct skl_clk *clkdev;
+	int ret;
+
+	clkdev = devm_kzalloc(dev, sizeof(*clkdev), GFP_KERNEL);
+	if (!clkdev)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = clk->name;
+	init.ops = &skl_clk_ops;
+	init.flags = CLK_SET_RATE_GATE;
+	init.parent_names = &clk->parent_name;
+	init.num_parents = 1;
+	clkdev->hw.init = &init;
+	clkdev->pdata = clk_pdata;
+
+	clkdev->id = id;
+	ret = devm_clk_hw_register(dev, &clkdev->hw);
+	if (ret) {
+		clkdev = ERR_PTR(ret);
+		return clkdev;
+	}
+
+	clkdev->lookup = clkdev_hw_create(&clkdev->hw, init.name, NULL);
+	if (!clkdev->lookup)
+		clkdev = ERR_PTR(-ENOMEM);
+
+	return clkdev;
+}
+
+static int skl_clk_dev_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device *parent_dev = dev->parent;
+	struct skl_clk_parent_src *parent_clks;
+	struct skl_clk_pdata *clk_pdata;
+	struct skl_clk_data *data;
+	struct skl_ssp_clk *clks;
+	int ret, i;
+
+	clk_pdata = dev_get_platdata(&pdev->dev);
+	parent_clks = clk_pdata->parent_clks;
+	clks = clk_pdata->ssp_clks;
+	if (!parent_clks || !clks)
+		return -EIO;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	/* Register Parent clock */
+	ret = skl_register_parent_clks(parent_dev, data->parent, parent_clks);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < clk_pdata->num_clks; i++) {
+		/*
+		 * Only register valid clocks
+		 * i.e. for which nhlt entry is present.
+		 */
+		if (clks[i].rate_cfg[0].rate == 0)
+			continue;
+
+		data->clk[i] = register_skl_clk(dev, &clks[i], clk_pdata, i);
+		if (IS_ERR(data->clk[i])) {
+			ret = PTR_ERR(data->clk[i]);
+			goto err_unreg_skl_clk;
+		}
+
+		data->avail_clk_cnt++;
+	}
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+
+err_unreg_skl_clk:
+	unregister_src_clk(data);
+	unregister_parent_src_clk(data->parent, SKL_MAX_CLK_SRC);
+
+	return ret;
+}
+
+static int skl_clk_dev_remove(struct platform_device *pdev)
+{
+	struct skl_clk_data *data;
+
+	data = platform_get_drvdata(pdev);
+	unregister_src_clk(data);
+	unregister_parent_src_clk(data->parent, SKL_MAX_CLK_SRC);
+
+	return 0;
+}
+
+static struct platform_driver skl_clk_driver = {
+	.driver = {
+		.name = "skl-ssp-clk",
+	},
+	.probe = skl_clk_dev_probe,
+	.remove = skl_clk_dev_remove,
+};
+
+module_platform_driver(skl_clk_driver);
+
+MODULE_DESCRIPTION("Skylake clock driver");
+MODULE_AUTHOR("Jaikrishna Nemallapudi <jaikrishnax.nemallapudi@intel.com>");
+MODULE_AUTHOR("Subhransu S. Prusty <subhransu.s.prusty@intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:skl-ssp-clk");

sound/soc/intel/skylake/skl-ssp-clk.h

@@ -54,8 +54,46 @@ struct skl_clk_parent_src {
 	const char *parent_name;
 };
 
+struct skl_tlv_hdr {
+	u32 type;
+	u32 size;
+};
+
+struct skl_dmactrl_mclk_cfg {
+	struct skl_tlv_hdr hdr;
+	/* DMA Clk TLV params */
+	u32 clk_warm_up:16;
+	u32 mclk:1;
+	u32 warm_up_over:1;
+	u32 rsvd0:14;
+	u32 clk_stop_delay:16;
+	u32 keep_running:1;
+	u32 clk_stop_over:1;
+	u32 rsvd1:14;
+};
+
+struct skl_dmactrl_sclkfs_cfg {
+	struct skl_tlv_hdr hdr;
+	/* DMA SClk&FS  TLV params */
+	u32 sampling_frequency;
+	u32 bit_depth;
+	u32 channel_map;
+	u32 channel_config;
+	u32 interleaving_style;
+	u32 number_of_channels : 8;
+	u32 valid_bit_depth : 8;
+	u32 sample_type : 8;
+	u32 reserved : 8;
+};
+
+union skl_clk_ctrl_ipc {
+	struct skl_dmactrl_mclk_cfg mclk;
+	struct skl_dmactrl_sclkfs_cfg sclk_fs;
+};
+
 struct skl_clk_rate_cfg_table {
 	unsigned long rate;
+	union skl_clk_ctrl_ipc dma_ctl_ipc;
 	void *config;
 };
 

sound/soc/intel/skylake/skl.h

@@ -38,6 +38,10 @@
 /* D0I3C Register fields */
 #define AZX_REG_VS_D0I3C_CIP      0x1 /* Command in progress */
 #define AZX_REG_VS_D0I3C_I3       0x4 /* D0i3 enable */
+#define SKL_MAX_DMACTRL_CFG	18
+#define DMA_CLK_CONTROLS	1
+#define DMA_TRANSMITION_START	2
+#define DMA_TRANSMITION_STOP	3
 
 struct skl_dsp_resource {
 	u32 max_mcps;
@@ -147,6 +151,8 @@ int skl_nhlt_create_sysfs(struct skl *skl);
 void skl_nhlt_remove_sysfs(struct skl *skl);
 void skl_get_clks(struct skl *skl, struct skl_ssp_clk *ssp_clks);
 struct skl_clk_parent_src *skl_get_parent_clk(u8 clk_id);
+int skl_dsp_set_dma_control(struct skl_sst *ctx, u32 *caps,
+				u32 caps_size, u32 node_id);
 
 struct skl_module_cfg;