Commit 67f4aaa2 authored by Michal Simek's avatar Michal Simek

microblaze: Support early console on uart16550

Early console support reuse setting from U-BOOT that's why
it is not necessary to setup baudrates, etc.
Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent 51f5fa50
...@@ -10,7 +10,7 @@ source "lib/Kconfig.debug" ...@@ -10,7 +10,7 @@ source "lib/Kconfig.debug"
config EARLY_PRINTK config EARLY_PRINTK
bool "Early printk function for kernel" bool "Early printk function for kernel"
depends on SERIAL_UARTLITE_CONSOLE depends on SERIAL_UARTLITE_CONSOLE || SERIAL_8250_CONSOLE
default n default n
help help
This option turns on/off early printk messages to console. This option turns on/off early printk messages to console.
......
...@@ -27,6 +27,7 @@ ...@@ -27,6 +27,7 @@
/* Other Prototypes */ /* Other Prototypes */
extern int early_uartlite_console(void); extern int early_uartlite_console(void);
extern int early_uart16550_console(void);
#ifdef CONFIG_PCI #ifdef CONFIG_PCI
/* /*
......
...@@ -65,6 +65,50 @@ static struct console early_serial_uartlite_console = { ...@@ -65,6 +65,50 @@ static struct console early_serial_uartlite_console = {
}; };
#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */ #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
#ifdef CONFIG_SERIAL_8250_CONSOLE
static void early_printk_uart16550_putc(char c)
{
/*
* Limit how many times we'll spin waiting for TX FIFO status.
* This will prevent lockups if the base address is incorrectly
* set, or any other issue on the UARTLITE.
* This limit is pretty arbitrary, unless we are at about 10 baud
* we'll never timeout on a working UART.
*/
#define UART_LSR_TEMT 0x40 /* Transmitter empty */
#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
unsigned retries = 10000;
while (--retries &&
!((in_be32(base_addr + 0x14) & BOTH_EMPTY) == BOTH_EMPTY))
;
if (retries)
out_be32(base_addr, c & 0xff);
}
static void early_printk_uart16550_write(struct console *unused,
const char *s, unsigned n)
{
while (*s && n-- > 0) {
early_printk_uart16550_putc(*s);
if (*s == '\n')
early_printk_uart16550_putc('\r');
s++;
}
}
static struct console early_serial_uart16550_console = {
.name = "earlyser",
.write = early_printk_uart16550_write,
.flags = CON_PRINTBUFFER,
.index = -1,
};
#endif /* CONFIG_SERIAL_8250_CONSOLE */
static struct console *early_console; static struct console *early_console;
void early_printk(const char *fmt, ...) void early_printk(const char *fmt, ...)
...@@ -103,6 +147,25 @@ int __init setup_early_printk(char *opt) ...@@ -103,6 +147,25 @@ int __init setup_early_printk(char *opt)
} }
#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */ #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
#ifdef CONFIG_SERIAL_8250_CONSOLE
base_addr = early_uart16550_console();
base_addr &= ~3; /* clear register offset */
if (base_addr) {
early_console_initialized = 1;
#ifdef CONFIG_MMU
early_console_reg_tlb_alloc(base_addr);
#endif
early_console = &early_serial_uart16550_console;
early_printk("early_printk_console is enabled at 0x%08x\n",
base_addr);
/* register_console(early_console); */
return 0;
}
#endif /* CONFIG_SERIAL_8250_CONSOLE */
return 1; return 1;
} }
......
...@@ -89,6 +89,40 @@ int __init early_uartlite_console(void) ...@@ -89,6 +89,40 @@ int __init early_uartlite_console(void)
{ {
return of_scan_flat_dt(early_init_dt_scan_serial, NULL); return of_scan_flat_dt(early_init_dt_scan_serial, NULL);
} }
/* MS this is Microblaze specifig function */
static int __init early_init_dt_scan_serial_full(unsigned long node,
const char *uname, int depth, void *data)
{
unsigned long l;
char *p;
unsigned int addr;
pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
/* find all serial nodes */
if (strncmp(uname, "serial", 6) != 0)
return 0;
early_init_dt_check_for_initrd(node);
/* find compatible node with uartlite */
p = of_get_flat_dt_prop(node, "compatible", &l);
if ((strncmp(p, "xlnx,xps-uart16550", 18) != 0) &&
(strncmp(p, "xlnx,axi-uart16550", 18) != 0))
return 0;
addr = *(u32 *)of_get_flat_dt_prop(node, "reg", &l);
addr += *(u32 *)of_get_flat_dt_prop(node, "reg-offset", &l);
return addr; /* return address */
}
/* this function is looking for early uartlite console - Microblaze specific */
int __init early_uart16550_console(void)
{
return of_scan_flat_dt(early_init_dt_scan_serial_full, NULL);
}
#endif #endif
void __init early_init_devtree(void *params) void __init early_init_devtree(void *params)
......
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