Re: [U-Boot] [PATCH v2 04/11] serial: Use a more precise baud rate generation for serial_s3c24x0

14 Sep 2012


      Dear José Miguel Gonçalves,
...
Program udivslot register in order to obtain a more precise baudrate.
More explanatory commit message would be nice.
[...]
...
+static const int udivslot[] = {
const array const members, no ?
...

0x0000, 0x0080, 0x0808, 0x0888, 0x2222, 0x4924, 0x4A52, 0x54AA,
0x5555, 0xD555, 0xD5D5, 0xDDD5, 0xDDDD, 0xDFDD, 0xDFDF, 0xFFDF,

+};


void _serial_setbrg(const int dev_index)
 {
   struct s3c24x0_uart *uart = s3c24x0_get_base_uart(dev_index);

unsigned int reg = 0;


u32 pclk;
u32 baudrate;
int i;


/* value is calculated so : (int)(PCLK/16./baudrate) -1 */
reg = get_PCLK() / (16 * gd->baudrate) - 1;


pclk = get_PCLK();
baudrate = gd->baudrate;


writel(reg, &uart->ubrdiv);


writel((pclk / baudrate / 16) - 1, &uart->ubrdiv);
writel(udivslot[(pclk / baudrate) % 16], &uart->udivslot);
for (i = 0; i < 100; i++)
/* Delay */ ;

}
Best regards,
Marek Vasut