ASoC: Intel: Skylake: Parse nhlt and register clock device

When NHLT endpoint is present for a SSP then we create clock for that SSP.

MCLK is consistent across endpoints and configuration for an SSP, so query
only for first endpoint for an SSP.

For SCLK/SCLKFS, the best fit is queried from the NHLT configurations which
matches the clock rate requested. Best fit is decided based on below:

1. If rate matches with multiple configurations, then the first
   configuration is selected.

2. If for a selected fs and bits_per_sample, there are multiple endpoint
   configuration match, then the configuration with max number of
   channels is selected. So, the user has to set the rate which fits
   max number of channels

So we create a platform device and pass clock information parsed as
platform data.

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>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/skylake/skl-i2s.h

@@ -0,0 +1,64 @@
+/*
+ *  skl-i2s.h - i2s blob mapping
+ *
+ *  Copyright (C) 2017 Intel Corp
+ *  Author: Subhransu S. Prusty < subhransu.s.prusty@intel.com>
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *  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; version 2 of the License.
+ *
+ *  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.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ */
+
+#ifndef __SOUND_SOC_SKL_I2S_H
+#define __SOUND_SOC_SKL_I2S_H
+
+#define SKL_I2S_MAX_TIME_SLOTS		8
+#define SKL_MCLK_DIV_CLK_SRC_MASK	GENMASK(17, 16)
+
+#define SKL_MNDSS_DIV_CLK_SRC_MASK	GENMASK(21, 20)
+#define SKL_SHIFT(x)			(ffs(x) - 1)
+#define SKL_MCLK_DIV_RATIO_MASK		GENMASK(11, 0)
+
+struct skl_i2s_config {
+	u32 ssc0;
+	u32 ssc1;
+	u32 sscto;
+	u32 sspsp;
+	u32 sstsa;
+	u32 ssrsa;
+	u32 ssc2;
+	u32 sspsp2;
+	u32 ssc3;
+	u32 ssioc;
+} __packed;
+
+struct skl_i2s_config_mclk {
+	u32 mdivctrl;
+	u32 mdivr;
+};
+
+/**
+ * struct skl_i2s_config_blob_legacy - Structure defines I2S Gateway
+ * configuration legacy blob
+ *
+ * @gtw_attr:		Gateway attribute for the I2S Gateway
+ * @tdm_ts_group:	TDM slot mapping against channels in the Gateway.
+ * @i2s_cfg:		I2S HW registers
+ * @mclk:		MCLK clock source and divider values
+ */
+struct skl_i2s_config_blob_legacy {
+	u32 gtw_attr;
+	u32 tdm_ts_group[SKL_I2S_MAX_TIME_SLOTS];
+	struct skl_i2s_config i2s_cfg;
+	struct skl_i2s_config_mclk mclk;
+};
+
+#endif /* __SOUND_SOC_SKL_I2S_H */

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

@@ -19,6 +19,7 @@
  */
 #include <linux/pci.h>
 #include "skl.h"
+#include "skl-i2s.h"
 
 /* Unique identification for getting NHLT blobs */
 static guid_t osc_guid =
@@ -262,3 +263,157 @@ void skl_nhlt_remove_sysfs(struct skl *skl)
 
 	sysfs_remove_file(&dev->kobj, &dev_attr_platform_id.attr);
 }
+
+/*
+ * Queries NHLT for all the fmt configuration for a particular endpoint and
+ * stores all possible rates supported in a rate table for the corresponding
+ * sclk/sclkfs.
+ */
+void skl_get_ssp_clks(struct skl *skl, struct skl_ssp_clk *ssp_clks,
+				struct nhlt_fmt *fmt, u8 id)
+{
+	struct skl_i2s_config_blob_legacy *i2s_config;
+	struct skl_clk_parent_src *parent;
+	struct skl_ssp_clk *sclk, *sclkfs;
+	struct nhlt_fmt_cfg *fmt_cfg;
+	struct wav_fmt_ext *wav_fmt;
+	unsigned long rate = 0;
+	bool present = false;
+	int rate_index = 0;
+	u16 channels, bps;
+	u8 clk_src;
+	int i, j;
+	u32 fs;
+
+	sclk = &ssp_clks[SKL_SCLK_OFS];
+	sclkfs = &ssp_clks[SKL_SCLKFS_OFS];
+
+	if (fmt->fmt_count == 0)
+		return;
+
+	for (i = 0; i < fmt->fmt_count; i++) {
+		fmt_cfg = &fmt->fmt_config[i];
+		wav_fmt = &fmt_cfg->fmt_ext;
+
+		channels = wav_fmt->fmt.channels;
+		bps = wav_fmt->fmt.bits_per_sample;
+		fs = wav_fmt->fmt.samples_per_sec;
+
+		/*
+		 * In case of TDM configuration on a ssp, there can
+		 * be more than one blob in which channel masks are
+		 * different for each usecase for a specific rate and bps.
+		 * But the sclk rate will be generated for the total
+		 * number of channels used for that endpoint.
+		 *
+		 * So for the given fs and bps, choose blob which has
+		 * the superset of all channels for that endpoint and
+		 * derive the rate.
+		 */
+		for (j = i; j < fmt->fmt_count; j++) {
+			fmt_cfg = &fmt->fmt_config[j];
+			wav_fmt = &fmt_cfg->fmt_ext;
+			if ((fs == wav_fmt->fmt.samples_per_sec) &&
+			   (bps == wav_fmt->fmt.bits_per_sample))
+				channels = max_t(u16, channels,
+						wav_fmt->fmt.channels);
+		}
+
+		rate = channels * bps * fs;
+
+		/* check if the rate is added already to the given SSP's sclk */
+		for (j = 0; (sclk[id].rate_cfg[j].rate != 0) &&
+				(j < SKL_MAX_CLK_RATES); j++) {
+			if (sclk[id].rate_cfg[j].rate == rate) {
+				present = true;
+				break;
+			}
+		}
+
+		/* Fill rate and parent for sclk/sclkfs */
+		if (!present) {
+			/* MCLK Divider Source Select */
+			i2s_config = (struct skl_i2s_config_blob_legacy *)
+						fmt->fmt_config[0].config.caps;
+			clk_src = ((i2s_config->mclk.mdivctrl)
+					& SKL_MNDSS_DIV_CLK_SRC_MASK) >>
+					SKL_SHIFT(SKL_MNDSS_DIV_CLK_SRC_MASK);
+
+			parent = skl_get_parent_clk(clk_src);
+
+			/*
+			 * Do not copy the config data if there is no parent
+			 * clock available for this clock source select
+			 */
+			if (!parent)
+				continue;
+
+			sclk[id].rate_cfg[rate_index].rate = rate;
+			sclk[id].rate_cfg[rate_index].config = fmt_cfg;
+			sclkfs[id].rate_cfg[rate_index].rate = rate;
+			sclkfs[id].rate_cfg[rate_index].config = fmt_cfg;
+			sclk[id].parent_name = parent->name;
+			sclkfs[id].parent_name = parent->name;
+
+			rate_index++;
+		}
+	}
+}
+
+void skl_get_mclk(struct skl *skl, struct skl_ssp_clk *mclk,
+				struct nhlt_fmt *fmt, u8 id)
+{
+	struct skl_i2s_config_blob_legacy *i2s_config;
+	struct nhlt_specific_cfg *fmt_cfg;
+	struct skl_clk_parent_src *parent;
+	u32 clkdiv, div_ratio;
+	u8 clk_src;
+
+	fmt_cfg = &fmt->fmt_config[0].config;
+	i2s_config = (struct skl_i2s_config_blob_legacy *)fmt_cfg->caps;
+
+	/* MCLK Divider Source Select */
+	clk_src = ((i2s_config->mclk.mdivctrl) & SKL_MCLK_DIV_CLK_SRC_MASK) >>
+					SKL_SHIFT(SKL_MCLK_DIV_CLK_SRC_MASK);
+
+	clkdiv = i2s_config->mclk.mdivr & SKL_MCLK_DIV_RATIO_MASK;
+
+	/* bypass divider */
+	div_ratio = 1;
+
+	if (clkdiv != SKL_MCLK_DIV_RATIO_MASK)
+		/* Divider is 2 + clkdiv */
+		div_ratio = clkdiv + 2;
+
+	/* Calculate MCLK rate from source using div value */
+	parent = skl_get_parent_clk(clk_src);
+	if (!parent)
+		return;
+
+	mclk[id].rate_cfg[0].rate = parent->rate/div_ratio;
+	mclk[id].rate_cfg[0].config = &fmt->fmt_config[0];
+	mclk[id].parent_name = parent->name;
+}
+
+void skl_get_clks(struct skl *skl, struct skl_ssp_clk *ssp_clks)
+{
+	struct nhlt_acpi_table *nhlt = (struct nhlt_acpi_table *)skl->nhlt;
+	struct nhlt_endpoint *epnt;
+	struct nhlt_fmt *fmt;
+	int i;
+	u8 id;
+
+	epnt = (struct nhlt_endpoint *)nhlt->desc;
+	for (i = 0; i < nhlt->endpoint_count; i++) {
+		if (epnt->linktype == NHLT_LINK_SSP) {
+			id = epnt->virtual_bus_id;
+
+			fmt = (struct nhlt_fmt *)(epnt->config.caps
+					+ epnt->config.size);
+
+			skl_get_ssp_clks(skl, ssp_clks, fmt, id);
+			skl_get_mclk(skl, ssp_clks, fmt, id);
+		}
+		epnt = (struct nhlt_endpoint *)((u8 *)epnt + epnt->length);
+	}
+}

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

@@ -0,0 +1,79 @@
+/*
+ *  skl-ssp-clk.h - Skylake ssp clock information and ipc structure
+ *
+ *  Copyright (C) 2017 Intel Corp
+ *  Author: Jaikrishna Nemallapudi <jaikrishnax.nemallapudi@intel.com>
+ *  Author: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
+ *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  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; version 2 of the License.
+ *
+ *  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.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ */
+
+#ifndef SOUND_SOC_SKL_SSP_CLK_H
+#define SOUND_SOC_SKL_SSP_CLK_H
+
+#define SKL_MAX_SSP		6
+/* xtal/cardinal/pll, parent of ssp clocks and mclk */
+#define SKL_MAX_CLK_SRC		3
+#define SKL_MAX_SSP_CLK_TYPES	3 /* mclk, sclk, sclkfs */
+
+#define SKL_MAX_CLK_CNT		(SKL_MAX_SSP * SKL_MAX_SSP_CLK_TYPES)
+
+/* Max number of configurations supported for each clock */
+#define SKL_MAX_CLK_RATES	10
+
+#define SKL_SCLK_OFS		SKL_MAX_SSP
+#define SKL_SCLKFS_OFS		(SKL_SCLK_OFS + SKL_MAX_SSP)
+
+enum skl_clk_type {
+	SKL_MCLK,
+	SKL_SCLK,
+	SKL_SCLK_FS,
+};
+
+enum skl_clk_src_type {
+	SKL_XTAL,
+	SKL_CARDINAL,
+	SKL_PLL,
+};
+
+struct skl_clk_parent_src {
+	u8 clk_id;
+	const char *name;
+	unsigned long rate;
+	const char *parent_name;
+};
+
+struct skl_clk_rate_cfg_table {
+	unsigned long rate;
+	void *config;
+};
+
+/*
+ * rate for mclk will be in rates[0]. For sclk and sclkfs, rates[] store
+ * all possible clocks ssp can generate for that platform.
+ */
+struct skl_ssp_clk {
+	const char *name;
+	const char *parent_name;
+	struct skl_clk_rate_cfg_table rate_cfg[SKL_MAX_CLK_RATES];
+};
+
+struct skl_clk_pdata {
+	struct skl_clk_parent_src *parent_clks;
+	int num_clks;
+	struct skl_ssp_clk *ssp_clks;
+	void *pvt_data;
+};
+
+#endif /* SOUND_SOC_SKL_SSP_CLK_H */