Hi Marek,
On 09/12/2012 10:01 PM, Marek Vasut wrote:
Dear José Miguel Gonçalves,
Serial driver for the S3C24XX SoCs.
Signed-off-by: José Miguel Gonçalves <jose.goncal...@inov.pt>
---
drivers/serial/Makefile | 1 +
drivers/serial/s3c24xx_serial.c | 146
+++++++++++++++++++++++++++++++++++++++ 2 files changed, 147 insertions(+)
create mode 100644 drivers/serial/s3c24xx_serial.c
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 65d0f23..2cbdaac 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -52,6 +52,7 @@ COBJS-$(CONFIG_PL011_SERIAL) += serial_pl01x.o
COBJS-$(CONFIG_PXA_SERIAL) += serial_pxa.o
COBJS-$(CONFIG_SA1100_SERIAL) += serial_sa1100.o
COBJS-$(CONFIG_S3C24X0_SERIAL) += serial_s3c24x0.o
+COBJS-$(CONFIG_S3C24XX_SERIAL) += s3c24xx_serial.o
What's the difference between those two drivers ?!
No substantial differences exists. The UART controller block is the same
in all S3C24XX chips. One difference is the number of UARTs. The more
recent chips (S3C2416 & S3C2450) have 4 instead of the 3 found on the
old ones. Besides that, the driver that I submitted uses a more precise
method for baudrate generation.
+
+#ifdef CONFIG_SERIAL0
+#define UART_NR S3C24XX_UART0
+
+#elif defined(CONFIG_SERIAL1)
+#define UART_NR S3C24XX_UART1
+
+#elif defined(CONFIG_SERIAL2)
+#define UART_NR S3C24XX_UART2
+
+#elif defined(CONFIG_SERIAL3)
+#define UART_NR S3C24XX_UART3
+
+#else
+#error "Bad: you didn't configure serial ..."
Error itself is "Bad:" so remove it
OK.
+#endif
+
+#define barrier() asm volatile("" ::: "memory")
Is that even used ?
Yes. Without it the GCC optimization removes the loop at the end of the
baurate generation routine.
+/*
+ * The coefficient, used to calculate the baudrate on S3C24XX UARTs is
+ * calculated as C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
+ * however, section 2.1.10 of the S3C2416 User's Manual doesn't recommend
+ * using 1 for 1, 3 for 2, ... (2^n - 1) for n, instead, they suggest
using + * these constants:
+ */
+static const int udivslot[] = {
const int const ... const array const members
It don't see the need for that because you have a constant array when
their members are constant and;
static const int udivslot[];
static int const udivslot[];
are both (correct) forms to declare an array of constant integers.
+ 0x0000, 0x0080, 0x0808, 0x0888, 0x2222, 0x4924, 0x4A52, 0x54AA,
+ 0x5555, 0xD555, 0xD5D5, 0xDDD5, 0xDDDD, 0xDFDD, 0xDFDF, 0xFFDF,
+};
+
+void serial_setbrg(void)
+{
+ s3c24xx_uart *const uart = s3c24xx_get_base_uart(UART_NR);
+ u32 pclk;
+ u32 baudrate;
+ int i;
+
+ pclk = get_PCLK();
+ baudrate = gd->baudrate;
+
+ uart->ubrdiv = (pclk / baudrate / 16) - 1;
+ uart->udivslot = udivslot[(pclk / baudrate) % 16];
+
+ for (i = 0; i < 100; i++)
+ barrier();
+}
+
+/*
+ * Initialise the serial port with the given baudrate. The settings
+ * are always 8 data bits, no parity, 1 stop bit, no start bits.
+ */
+int serial_init(void)
+{
+ s3c24xx_uart *const uart = s3c24xx_get_base_uart(UART_NR);
+
+ /* FIFO enable, Tx/Rx FIFO clear */
+ uart->ufcon = 0x07;
+ uart->umcon = 0x00;
Magic numbers, fix
OK.
Can you implement it as a serial multi (CONFIG_SERIAL_MULTI) right away ?
thanks.
I will look at that option and change the driver to support it.
Best regards,
José Gonçalves
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