[U-Boot] [PATCH] x86: baytrail: Add SIO HS-UART clock setup

[Stefan Roese]

To support the BayTrail internal SIO HS UART, the internal UART clock
needs to get configured. This patch adds support for this clock
configuration which will be done, if the PCI device(s) are found.

Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Simon Glass <sjg at chromium.org>
Cc: Bin Meng <bmeng.cn at gmail.com>
---
 arch/x86/cpu/baytrail/cpu.c | 52 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/arch/x86/cpu/baytrail/cpu.c b/arch/x86/cpu/baytrail/cpu.c
index b1faf8c..87e0382 100644
--- a/arch/x86/cpu/baytrail/cpu.c
+++ b/arch/x86/cpu/baytrail/cpu.c
@@ -9,12 +9,64 @@
 #include <common.h>
 #include <cpu.h>
 #include <dm.h>
+#include <pci.h>
 #include <asm/cpu.h>
 #include <asm/cpu_x86.h>
+#include <asm/io.h>
 #include <asm/lapic.h>
 #include <asm/msr.h>
 #include <asm/turbo.h>
 
+#define BYT_PRV_CLK			0x800
+#define BYT_PRV_CLK_EN			(1 << 0)
+#define BYT_PRV_CLK_M_VAL_SHIFT		1
+#define BYT_PRV_CLK_N_VAL_SHIFT		16
+#define BYT_PRV_CLK_UPDATE		(1 << 31)
+
+#define BYT_HSUART0			PCI_BDF(0, 0x1e, 0x3)
+#define BYT_HSUART1			PCI_BDF(0, 0x1e, 0x4)
+
+static void hsuart_clock_set(void *base)
+{
+	u32 m, n, reg;
+
+	/*
+	 * Configure the BayTrail UART clock for the internal HS UARTs
+	 * (PCI devices) to 58982400 Hz
+	 */
+	m = 0x2400;
+	n = 0x3d09;
+	reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
+	writel(reg, base + BYT_PRV_CLK);
+	reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
+	writel(reg, base + BYT_PRV_CLK);
+}
+
+/*
+ * Configure the internal clock of both SIO HS-UARTs, if they are enabled
+ * via FSP
+ */
+int arch_cpu_init_dm(void)
+{
+	struct udevice *dev;
+	void *base;
+	int ret;
+
+	ret = dm_pci_bus_find_bdf(BYT_HSUART0, &dev);
+	if (!ret) {
+		base = dm_pci_map_bar(dev, PCI_BASE_ADDRESS_0, PCI_REGION_MEM);
+		hsuart_clock_set(base);
+	}
+
+	ret = dm_pci_bus_find_bdf(BYT_HSUART1, &dev);
+	if (!ret) {
+		base = dm_pci_map_bar(dev, PCI_BASE_ADDRESS_0, PCI_REGION_MEM);
+		hsuart_clock_set(base);
+	}
+
+	return 0;
+}
+
 static void set_max_freq(void)
 {
 	msr_t perf_ctl;
-- 
2.9.2