soc/braswell: Fix DSP clock

The codec clock frequency was incorrectly set to 25MHz.
The only available frequency is 19.2MHz through external clock and PLL.

Original-Reviewed-on: https://chromium-review.googlesource.com/295768
Original-Tested-by: Hannah Williams <hannah.williams@intel.com>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>

Change-Id: I9bef334a5a3aaee28fcc4937180896ff49969bc5
Signed-off-by: Felix Durairaj <felixx.durairaj@intel.com>
Reviewed-on: https://review.coreboot.org/12732
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/mainboard/google/cyan/devicetree.cb

@@ -72,8 +72,7 @@ chip soc/intel/braswell
 	register "ISPPciDevConfig" = "3"
 
 	# LPE audio codec settings
-	register "lpe_codec_clk_freq" = "25" # 25MHz clock
-	register "lpe_codec_clk_num" = "0"   # PMC_PLT_CLK[0]
+	register "lpe_codec_clk_src" = "LPE_CLK_SRC_XTAL" # 19.2MHz clock
 
 	# Enable devices in ACPI mode
 	register "lpss_acpi_mode" = "1"

src/mainboard/intel/strago/devicetree.cb

@@ -72,8 +72,7 @@ chip soc/intel/braswell
 	register "ISPPciDevConfig" = "3"
 
 	# LPE audio codec settings
-	register "lpe_codec_clk_freq" = "25" # 25MHz clock
-	register "lpe_codec_clk_num" = "0"   # PMC_PLT_CLK[0]
+	register "lpe_codec_clk_src" = "LPE_CLK_SRC_XTAL" # 19.2MHz clock
 
 	# Enable devices in ACPI mode
 	register "lpss_acpi_mode" = "1"

src/soc/intel/braswell/chip.h

@@ -33,6 +33,11 @@
 #define MEM_DDR3	0
 #define MEM_LPDDR3	1
 
+enum lpe_clk_src {
+        LPE_CLK_SRC_XTAL,
+        LPE_CLK_SRC_PLL,
+};
+
 struct soc_intel_braswell_config {
 	uint8_t enable_xdp_tap;
 	uint8_t clkreq_enable;
@@ -41,8 +46,7 @@ struct soc_intel_braswell_config {
 	int disable_slp_x_stretch_sus_fail;
 
 	/* LPE Audio Clock configuration. */
-	int lpe_codec_clk_freq; /* 19 or 25 are valid. */
-	int lpe_codec_clk_num; /* Platform clock pins. [0:5] are valid. */
+	enum lpe_clk_src lpe_codec_clk_src; /* 0=xtal 1=PLL, Both are 19.2Mhz. */
 
 	/* Native SD Card controller - override controller capabilities. */
 	uint32_t sdcard_cap_low;

src/soc/intel/braswell/include/soc/pm.h

@@ -116,8 +116,8 @@
 #define PLT_CLK_CTL_3	0x6c
 #define PLT_CLK_CTL_4	0x70
 #define PLT_CLK_CTL_5	0x74
-#	define CLK_FREQ_25MHZ	(0x0 << 2)
-#	define CLK_FREQ_19P2MHZ	(0x1 << 2)
+#	define CLK_SRC_XTAL	(0x0 << 2)
+#	define CLK_SRC_PLL	(0x1 << 2)
 #	define CLK_CTL_D3_LPE	(0x0 << 0)
 #	define CLK_CTL_ON	(0x1 << 0)
 #	define CLK_CTL_OFF	(0x2 << 0)

src/soc/intel/braswell/lpe.c

@@ -96,32 +96,30 @@ static void setup_codec_clock(device_t dev)
 	const char *freq_str;
 
 	config = dev->chip_info;
-	switch (config->lpe_codec_clk_freq) {
-	case 19:
-		freq_str = "19.2";
-		reg = CLK_FREQ_19P2MHZ;
+	switch (config->lpe_codec_clk_src) {
+	case LPE_CLK_SRC_XTAL:
+		/* XTAL driven bit2=0 */
+		freq_str = "19.2MHz External Crystal";
+		reg = CLK_SRC_XTAL;
 		break;
-	case 25:
-		freq_str = "25";
-		reg = CLK_FREQ_25MHZ;
+	case LPE_CLK_SRC_PLL:
+		/* PLL driven bit2=1 */
+		freq_str = "19.2MHz PLL";
+		reg = CLK_SRC_PLL;
 		break;
 	default:
-		printk(BIOS_DEBUG, "LPE codec clock not required.\n");
+		reg = CLK_SRC_XTAL;
+		printk(BIOS_DEBUG, "LPE codec clock default to using Crystal\n");
 		return;
 	}
 
 	/* Default to always running. */
 	reg |= CLK_CTL_ON;
 
-	if (config->lpe_codec_clk_num < 0 || config->lpe_codec_clk_num > 5) {
-		printk(BIOS_DEBUG, "Invalid LPE codec clock number.\n");
-		return;
-	}
 
 	printk(BIOS_DEBUG, "LPE Audio codec clock set to %sMHz.\n", freq_str);
 
 	clk_reg = (u32 *) (PMC_BASE_ADDRESS + PLT_CLK_CTL_0);
-	clk_reg += config->lpe_codec_clk_num;
 
 	write32(clk_reg, (read32(clk_reg) & ~0x7) | reg);
 }