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serial: imx: Switch to nbcon console

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Implements the necessary callbacks to switch the imx console driver to
perform as an nbcon console.

Add implementations for the nbcon consoles (write_atomic, write_thread,
driver_enter, driver_exit) and add CON_NBCON to the initial flags.

The legacy code is kept in order to easily switch back to legacy mode
by defining CONFIG_SERIAL_IMX_LEGACY_CONSOLE.

Signed-off-by: Esben Haabendal <esben@geanix.com>
Link: https://lore.kernel.org/r/20240913-serial-imx-nbcon-v3-1-4c627302335b@geanix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Esben Haabendal 2024-09-13 10:52:19 +02:00 committed by Greg Kroah-Hartman
parent fd29e1e4e6
commit 70acca67bd
1 changed files with 101 additions and 19 deletions
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120
drivers/tty/serial/imx.c
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@ -230,6 +230,8 @@ struct imx_port {
unsigned int saved_reg[10];
bool context_saved;
bool last_putchar_was_newline;
enum imx_tx_state tx_state;
struct hrtimer trigger_start_tx;
struct hrtimer trigger_stop_tx;
@ -2064,26 +2066,34 @@ static void imx_uart_console_putchar(struct uart_port *port, unsigned char ch)
barrier();
imx_uart_writel(sport, ch, URTX0);
sport->last_putchar_was_newline = (ch == '\n');
}
/*
* Interrupts are disabled on entering
*/
static void
imx_uart_console_write(struct console *co, const char *s, unsigned int count)
static void imx_uart_console_device_lock(struct console *co, unsigned long *flags)
{
struct uart_port *up = &imx_uart_ports[co->index]->port;
return __uart_port_lock_irqsave(up, flags);
}
static void imx_uart_console_device_unlock(struct console *co, unsigned long flags)
{
struct uart_port *up = &imx_uart_ports[co->index]->port;
return __uart_port_unlock_irqrestore(up, flags);
}
static void imx_uart_console_write_atomic(struct console *co,
struct nbcon_write_context *wctxt)
{
struct imx_port *sport = imx_uart_ports[co->index];
struct uart_port *port = &sport->port;
struct imx_port_ucrs old_ucr;
unsigned long flags;
unsigned int ucr1, usr2;
int locked = 1;
if (sport->port.sysrq)
locked = 0;
else if (oops_in_progress)
locked = uart_port_trylock_irqsave(&sport->port, &flags);
else
uart_port_lock_irqsave(&sport->port, &flags);
if (!nbcon_enter_unsafe(wctxt))
return;
/*
* First, save UCR1/2/3 and then disable interrupts
@ -2097,10 +2107,12 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
uart_console_write(&sport->port, s, count, imx_uart_console_putchar);
if (!sport->last_putchar_was_newline)
uart_console_write(port, "\n", 1, imx_uart_console_putchar);
uart_console_write(port, wctxt->outbuf, wctxt->len,
imx_uart_console_putchar);
/*
* Finally, wait for transmitter to become empty
@ -2110,8 +2122,73 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
0, USEC_PER_SEC, false, sport, USR2);
imx_uart_ucrs_restore(sport, &old_ucr);
if (locked)
uart_port_unlock_irqrestore(&sport->port, flags);
nbcon_exit_unsafe(wctxt);
}
static void imx_uart_console_write_thread(struct console *co,
struct nbcon_write_context *wctxt)
{
struct imx_port *sport = imx_uart_ports[co->index];
struct uart_port *port = &sport->port;
struct imx_port_ucrs old_ucr;
unsigned int ucr1, usr2;
if (!nbcon_enter_unsafe(wctxt))
return;
/*
* First, save UCR1/2/3 and then disable interrupts
*/
imx_uart_ucrs_save(sport, &old_ucr);
ucr1 = old_ucr.ucr1;
if (imx_uart_is_imx1(sport))
ucr1 |= IMX1_UCR1_UARTCLKEN;
ucr1 |= UCR1_UARTEN;
ucr1 &= ~(UCR1_TRDYEN | UCR1_RRDYEN | UCR1_RTSDEN);
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_writel(sport, old_ucr.ucr2 | UCR2_TXEN, UCR2);
if (nbcon_exit_unsafe(wctxt)) {
int len = READ_ONCE(wctxt->len);
int i;
/*
* Write out the message. Toggle unsafe for each byte in order
* to give another (higher priority) context the opportunity
* for a friendly takeover. If such a takeover occurs, this
* context must reacquire ownership in order to perform final
* actions (such as re-enabling the interrupts).
*
* IMPORTANT: wctxt->outbuf and wctxt->len are no longer valid
* after a reacquire so writing the message must be
* aborted.
*/
for (i = 0; i < len; i++) {
if (!nbcon_enter_unsafe(wctxt))
break;
uart_console_write(port, wctxt->outbuf + i, 1,
imx_uart_console_putchar);
if (!nbcon_exit_unsafe(wctxt))
break;
}
}
while (!nbcon_enter_unsafe(wctxt))
nbcon_reacquire_nobuf(wctxt);
/*
* Finally, wait for transmitter to become empty
* and restore UCR1/2/3
*/
read_poll_timeout(imx_uart_readl, usr2, usr2 & USR2_TXDC,
0, USEC_PER_SEC, false, sport, USR2);
imx_uart_ucrs_restore(sport, &old_ucr);
nbcon_exit_unsafe(wctxt);
}
/*
@ -2203,6 +2280,8 @@ imx_uart_console_setup(struct console *co, char *options)
if (retval)
goto error_console;
sport->last_putchar_was_newline = true;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
@ -2239,11 +2318,14 @@ imx_uart_console_exit(struct console *co)
static struct uart_driver imx_uart_uart_driver;
static struct console imx_uart_console = {
.name = DEV_NAME,
.write = imx_uart_console_write,
.write_atomic = imx_uart_console_write_atomic,
.write_thread = imx_uart_console_write_thread,
.device_lock = imx_uart_console_device_lock,
.device_unlock = imx_uart_console_device_unlock,
.flags = CON_PRINTBUFFER | CON_NBCON,
.device = uart_console_device,
.setup = imx_uart_console_setup,
.exit = imx_uart_console_exit,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &imx_uart_uart_driver,
};