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| author | Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> | 2025-01-16 21:22:47 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-21 15:49:44 +0300 |
| commit | 77c97ed7c86380e12164c0741ff52a10d9ab0934 (patch) | |
| tree | 5bb143c16c3c4240295d9da4bd18cf3a1842ea30 | |
| parent | cf174b3c1bd3378a802ab2041733a579193a6f89 (diff) | |
| download | linux-77c97ed7c86380e12164c0741ff52a10d9ab0934.tar.xz | |
serial: sh-sci: Do not probe the serial port if its slot in sci_ports[] is in use
commit 9f7dea875cc7f9c1a56a5c688290634a59cd1420 upstream.
In the sh-sci driver, sci_ports[0] is used by earlycon. If the earlycon is
still active when sci_probe() is called and the new serial port is supposed
to map to sci_ports[0], return -EBUSY to prevent breaking the earlycon.
This situation should occurs in debug scenarios, and users should be
aware of the potential conflict.
Fixes: 0b0cced19ab1 ("serial: sh-sci: Add CONFIG_SERIAL_EARLYCON support")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20250116182249.3828577-4-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/sh-sci.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 53d5aae89be8..6182ae5f6fa1 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -165,6 +165,7 @@ struct sci_port { static struct sci_port sci_ports[SCI_NPORTS]; static unsigned long sci_ports_in_use; static struct uart_driver sci_uart_driver; +static bool sci_uart_earlycon; static inline struct sci_port * to_sci_port(struct uart_port *uart) @@ -3318,6 +3319,7 @@ static int sci_probe_single(struct platform_device *dev, static int sci_probe(struct platform_device *dev) { struct plat_sci_port *p; + struct resource *res; struct sci_port *sp; unsigned int dev_id; int ret; @@ -3347,6 +3349,26 @@ static int sci_probe(struct platform_device *dev) } sp = &sci_ports[dev_id]; + + /* + * In case: + * - the probed port alias is zero (as the one used by earlycon), and + * - the earlycon is still active (e.g., "earlycon keep_bootcon" in + * bootargs) + * + * defer the probe of this serial. This is a debug scenario and the user + * must be aware of it. + * + * Except when the probed port is the same as the earlycon port. + */ + + res = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + if (sci_uart_earlycon && sp == &sci_ports[0] && sp->port.mapbase != res->start) + return dev_err_probe(&dev->dev, -EBUSY, "sci_port[0] is used by earlycon!\n"); + platform_set_drvdata(dev, sp); ret = sci_probe_single(dev, dev_id, p, sp); @@ -3445,6 +3467,7 @@ static int __init early_console_setup(struct earlycon_device *device, port_cfg.type = type; sci_ports[0].cfg = &port_cfg; sci_ports[0].params = sci_probe_regmap(&port_cfg); + sci_uart_earlycon = true; port_cfg.scscr = sci_serial_in(&sci_ports[0].port, SCSCR); sci_serial_out(&sci_ports[0].port, SCSCR, SCSCR_RE | SCSCR_TE | port_cfg.scscr); |