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Fix UART initialization and support early and cmdline specified serial consoles #304

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merged 4 commits into from
Sep 8, 2023
Merged

Fix UART initialization and support early and cmdline specified serial consoles #304

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9d2f950
drivers,uart: verify if uart port is ready (exists)
wipawel Sep 6, 2023
88e7896
console: do not register same console callbacks twice
wipawel Sep 6, 2023
bf221cd
serial,console: fix early and cmdline serial consoles
wipawel Sep 6, 2023
3f93930
driver,uart: do not panic when UART port not ready
wipawel Sep 7, 2023
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12 changes: 12 additions & 0 deletions common/console.c
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Original file line number Diff line number Diff line change
Expand Up @@ -105,7 +105,19 @@ void fb_console_write(void *fb_memory, const char *buf, size_t len) {
fb_write(fb_memory, buf, len, FB_WHITE);
}

static inline bool is_console_callback_registered(console_callback_t cb, void *arg) {
for (unsigned int i = 0; i < num_console_callbacks; i++) {
if (console_callbacks[i].cb == cb && console_callbacks[i].arg == arg)
return true;
}

return false;
}

void register_console_callback(console_callback_t cb, void *arg) {
if (is_console_callback_registered(cb, arg))
return;

console_callbacks[num_console_callbacks].cb = cb;
console_callbacks[num_console_callbacks++].arg = arg;
}
Expand Down
52 changes: 36 additions & 16 deletions common/setup.c
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Expand Up @@ -68,27 +68,45 @@ unsigned long cpu_frequency;

#define QEMU_CONSOLE_PORT 0x0e9

static void __text_init init_console(void) {
uart_config_t cfg = {0};

if (!parse_com_port(COM1, &cfg)) {
/* Use first COM port indicated by BIOS (if none, use COM1) */
cfg.port = get_first_com_port();
cfg.baud = DEFAULT_BAUD_SPEED;
cfg.frame_size = COM_FRAME_SIZE_8_BITS;
cfg.parity = COM_NO_PARITY;
cfg.stop_bit = COM_STOP_BIT_1;
}
init_uart(&cfg);
register_console_callback(serial_console_write, _ptr(cfg.port));
static inline int __text_init init_uart_console(com_idx_t com, const uart_config_t *cfg) {
int rc = init_uart(com, cfg);

if (rc != 0)
return rc;

register_console_callback(serial_console_write, _ptr(cfg->port));
printk("Serial console at: ");
display_uart_config(com, cfg);

return rc;
}

static void __text_init init_early_console(void) {
uart_config_t cfg;

/* Use first COM port indicated by BIOS (if none, use COM1) */
cfg.port = get_first_com_port();
cfg.baud = DEFAULT_BAUD_SPEED;
cfg.frame_size = COM_FRAME_SIZE_8_BITS;
cfg.parity = COM_NO_PARITY;
cfg.stop_bit = COM_STOP_BIT_1;

init_uart_console(COM1, &cfg);

if (opt_qemu_console) {
register_console_callback(qemu_console_write, _ptr(QEMU_CONSOLE_PORT));
printk("Initialized QEMU console at port 0x%x", QEMU_CONSOLE_PORT);
}
}

printk("Serial console at: ");
display_uart_config(&cfg);
static void __text_init init_serial_consoles(void) {
uart_config_t cfg;

for (com_idx_t com = COM1; com < MAX_COM; com++) {
memset(&cfg, 0, sizeof(cfg));
if (parse_com_port(com, &cfg))
init_uart_console(com, &cfg);
}
}

static __always_inline void zero_bss(void) {
Expand Down Expand Up @@ -166,7 +184,7 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic, unsigned long
zero_bss();

/* Initialize console early */
init_console();
init_early_console();

if (multiboot_magic == MULTIBOOT2_BOOTLOADER_MAGIC) {
/* Indentity mapping is still on, so fill in multiboot structures */
Expand All @@ -178,6 +196,8 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic, unsigned long
if (!string_empty(kernel_cmdline))
printk("Command line: %s\n", kernel_cmdline);

init_serial_consoles();

init_boot_traps();

init_real_mode();
Expand Down
49 changes: 31 additions & 18 deletions drivers/serial.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <apic.h>
#include <errno.h>
#include <ioapic.h>
#include <ktf.h>
#include <lib.h>
Expand All @@ -39,15 +40,15 @@ static struct {

io_port_t __data_rmode com_ports[4];

static inline const char *com_port_name(com_port_t port) {
switch (port) {
case COM1_PORT:
static inline const char *com_name(com_idx_t com) {
switch (com) {
case COM1:
return "COM1";
case COM2_PORT:
case COM2:
return "COM2";
case COM3_PORT:
case COM3:
return "COM3";
case COM4_PORT:
case COM4:
return "COM4";
default:
BUG();
Expand All @@ -68,8 +69,8 @@ static const char com_parity_names[] = {

#define COM_STOP_BIT_VALUE(cfg) ((cfg)->stop_bit + 1)

void display_uart_config(const uart_config_t *cfg) {
printk("[%s] 0x%x %u,%u%c%u\n", com_port_name(cfg->port), cfg->port, cfg->baud,
void display_uart_config(com_idx_t com, const uart_config_t *cfg) {
printk("[%s] 0x%x %u,%u%c%u\n", com_name(com), cfg->port, cfg->baud,
com_frame_size_values[cfg->frame_size], com_parity_names[cfg->parity],
COM_STOP_BIT_VALUE(cfg));
}
Expand All @@ -94,7 +95,7 @@ static inline void set_dlab(io_port_t port, bool dlab) {
outb(port + UART_LCR_REG_OFFSET, lcr.reg);
}

static inline void set_port_mode(uart_config_t *cfg) {
static inline void set_port_mode(const uart_config_t *cfg) {
lcr_t lcr = {0};

/* Set baud speed by applying divisor to DLL+DLH */
Expand Down Expand Up @@ -124,7 +125,20 @@ static inline bool receiver_ready(io_port_t port) {
return msr.dsr && msr.cts;
}

void __text_init init_uart(uart_config_t *cfg) {
#define PORT_TIMEOUT 100 /* ~100ms */
static inline int uart_port_ready(io_port_t port) {
unsigned retries = PORT_TIMEOUT;

do {
if (receiver_ready(port))
return 0;
io_delay();
} while (retries--);

return -ENODEV;
}

int __text_init init_uart(com_idx_t com, const uart_config_t *cfg) {
mcr_t mcr = {0};
fcr_t fcr = {0};
ier_t ier = {0};
Expand All @@ -151,8 +165,9 @@ void __text_init init_uart(uart_config_t *cfg) {
mcr.aux = 2;
outb(cfg->port + UART_MCR_REG_OFFSET, mcr.reg);

if (com_ports[0] == NO_COM_PORT)
com_ports[0] = cfg->port;
com_ports[com] = cfg->port;

return uart_port_ready(cfg->port);
}

void __text_init init_uart_input(const cpu_t *cpu) {
Expand All @@ -168,11 +183,11 @@ void __text_init init_uart_input(const cpu_t *cpu) {

static inline int uart_port_status(io_port_t port) {
if (!receiver_ready(port))
return -1; /* ENODEV */
return -ENODEV;

if (!thr_empty(port)) {
io_delay();
return 1; /* EAGAIN */
return -EAGAIN;
}

return 0;
Expand Down Expand Up @@ -203,8 +218,7 @@ int serial_putchar(io_port_t port, char c) {

do {
rc = uart_putc(port, c);
BUG_ON(rc < 0);
} while (rc > 0 && retries--);
} while (rc == -EAGAIN && retries--);

return rc;
}
Expand All @@ -215,8 +229,7 @@ int serial_write(io_port_t port, const char *buf, size_t len) {

do {
rc = uart_puts(port, buf, len);
BUG_ON(rc < 0);
} while (rc > 0 && retries--);
} while (rc == -EAGAIN && retries--);

return rc;
}
Expand Down
5 changes: 3 additions & 2 deletions include/drivers/serial.h
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ enum com_idx {
COM2 = 1,
COM3 = 2,
COM4 = 3,
MAX_COM,
};
typedef enum com_idx com_idx_t;

Expand Down Expand Up @@ -199,12 +200,12 @@ typedef enum com_irq com_irq_t;
extern io_port_t com_ports[4];

extern io_port_t get_first_com_port(void);
extern void init_uart(uart_config_t *cfg);
extern int init_uart(com_idx_t com, const uart_config_t *cfg);
extern void init_uart_input(const cpu_t *cpu);
extern void uart_interrupt_handler(void);
extern int serial_putchar(io_port_t port, char c);
extern int serial_write(io_port_t port, const char *buf, size_t len);

extern void display_uart_config(const uart_config_t *cfg);
extern void display_uart_config(com_idx_t com, const uart_config_t *cfg);

#endif /* KTF_DRV_SERIAL_H */