[PATCH 5/8] i.MX: serial: Add setup_uart_ll function

[Andrey Smirnov]

It appears that all i.MX based boards that support early debug output
inevitably do exactly the same thing with the registers of the UART
peripheral. So to avoid code duplication distill that functionality
into dedicated subroutine.

IMPORTANT: Please note that 'setup_uart_ll' function does add a slight
difference in behaviour by dropping the initialization of ONEMS and
UESC registers since those do not seem to be needed for early UART
functionality

Signed-off-by: Andrey Smirnov <andrew.smirnov at gmail.com>
---
 arch/arm/mach-imx/include/mach/debug_ll.h | 34 +++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/arch/arm/mach-imx/include/mach/debug_ll.h b/arch/arm/mach-imx/include/mach/debug_ll.h
index 1c9f3a6..5b0b33b 100644
--- a/arch/arm/mach-imx/include/mach/debug_ll.h
+++ b/arch/arm/mach-imx/include/mach/debug_ll.h
@@ -30,10 +30,12 @@
 #define IMX_DEBUG_SOC MX35
 #elif defined CONFIG_DEBUG_IMX51_UART
 #define IMX_DEBUG_SOC MX51
+#define IMX_DEBUG_UART_REFCLOCK_HZ 54000000
 #elif defined CONFIG_DEBUG_IMX53_UART
 #define IMX_DEBUG_SOC MX53
 #elif defined CONFIG_DEBUG_IMX6Q_UART
 #define IMX_DEBUG_SOC MX6
+#define IMX_DEBUG_UART_REFCLOCK_HZ 80000000
 #else
 #error "unknown i.MX debug uart soc type"
 #endif
@@ -41,6 +43,34 @@
 #define __IMX_UART_BASE(soc, num) soc##_UART##num##_BASE_ADDR
 #define IMX_UART_BASE(soc, num) __IMX_UART_BASE(soc, num)

+
+#if defined IMX_DEBUG_UART_REFCLOCK_HZ
+
+static inline void setup_uart_ll(void)
+{
+	void __iomem *uartbase =
+	  (void *)IMX_UART_BASE(IMX_DEBUG_SOC,
+				CONFIG_DEBUG_IMX_UART_PORT);
+
+	writel(0x00000000, uartbase + UCR1);
+
+	writel(UCR2_IRTS | UCR2_WS | UCR2_TXEN | UCR2_RXEN | UCR2_SRST,
+	       uartbase + UCR2);
+	writel(UCR3_DSR | UCR3_DCD | UCR3_RI | UCR3_ADNIMP | UCR3_RXDMUXSEL,
+	       uartbase + UCR3);
+	writel((0b10 << UFCR_TXTL_SHF) | UFCR_RFDIV1 | (1 << UFCR_RXTL_SHF),
+	       uartbase + UFCR);
+
+	writel(baudrate_to_ubir(CONFIG_BAUDRATE),
+	       uartbase + UBIR);
+	writel(refclock_to_ubmr(IMX_DEBUG_UART_REFCLOCK_HZ),
+	       uartbase + UBMR);
+
+	writel(UCR1_UARTEN, uartbase + UCR1);
+}
+
+#endif
+
 static inline void PUTC_LL(int c)
 {
 	void __iomem *base = (void *)IMX_UART_BASE(IMX_DEBUG_SOC,
@@ -56,5 +86,9 @@ static inline void PUTC_LL(int c)

 	writel(c, base + URTX0);
 }
+#else
+static inline void setup_uart_ll(void)
+{
+}
 #endif /* CONFIG_DEBUG_LL */
 #endif /* __MACH_DEBUG_LL_H__ */
--
2.1.4