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Add early printf support, wrapped in #if 0 because it's only rarely needed.

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This commit is contained in:
Ian Lepore 2014-02-20 14:29:59 +00:00
parent e42bd24a5e
commit 8df34dd25b
1 changed files with 24 additions and 0 deletions
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24
sys/arm/freescale/imx/imx6_machdep.c
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@ -190,3 +190,27 @@ u_int imx_soc_type()
return (IMXSOC_6Q);
}
/*
* Early putc routine for EARLY_PRINTF support. To use, add to kernel config:
* option SOCDEV_PA=0x02000000
* option SOCDEV_VA=0x02000000
* option EARLY_PRINTF
* Resist the temptation to change the #if 0 to #ifdef EARLY_PRINTF here. It
* makes sense now, but if multiple SOCs do that it will make early_putc another
* duplicate symbol to be eliminated on the path to a generic kernel.
*/
#if 0
static void
imx6_early_putc(int c)
{
volatile uint32_t * UART_STAT_REG = (uint32_t *)0x02020098;
volatile uint32_t * UART_TX_REG = (uint32_t *)0x02020040;
const uint32_t UART_TXRDY = (1 << 3);
while ((*UART_STAT_REG & UART_TXRDY) == 0)
continue;
*UART_TX_REG = c;
}
early_putc_t *early_putc = imx6_early_putc;
#endif