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path: root/drivers/tty/serial/sh-sci.c
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Diffstat (limited to 'drivers/tty/serial/sh-sci.c')
-rw-r--r--drivers/tty/serial/sh-sci.c166
1 files changed, 145 insertions, 21 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index f43059e1b5c2..53236e3e4fa4 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -104,6 +104,20 @@ struct plat_sci_reg {
u8 offset, size;
};
+struct sci_suspend_regs {
+ u16 scdl;
+ u16 sccks;
+ u16 scsmr;
+ u16 scscr;
+ u16 scfcr;
+ u16 scsptr;
+ u16 hssrr;
+ u16 scpcr;
+ u16 scpdr;
+ u8 scbrr;
+ u8 semr;
+};
+
struct sci_port_params {
const struct plat_sci_reg regs[SCIx_NR_REGS];
unsigned int fifosize;
@@ -134,6 +148,8 @@ struct sci_port {
struct dma_chan *chan_tx;
struct dma_chan *chan_rx;
+ struct reset_control *rstc;
+
#ifdef CONFIG_SERIAL_SH_SCI_DMA
struct dma_chan *chan_tx_saved;
struct dma_chan *chan_rx_saved;
@@ -153,6 +169,7 @@ struct sci_port {
int rx_trigger;
struct timer_list rx_fifo_timer;
int rx_fifo_timeout;
+ struct sci_suspend_regs suspend_regs;
u16 hscif_tot;
bool has_rtscts;
@@ -166,6 +183,7 @@ 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 bool sci_uart_earlycon_dev_probing;
static inline struct sci_port *
to_sci_port(struct uart_port *uart)
@@ -2297,7 +2315,7 @@ static void sci_shutdown(struct uart_port *port)
dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
s->autorts = false;
- mctrl_gpio_disable_ms(to_sci_port(port)->gpios);
+ mctrl_gpio_disable_ms_sync(to_sci_port(port)->gpios);
uart_port_lock_irqsave(port, &flags);
sci_stop_rx(port);
@@ -3057,10 +3075,6 @@ static int sci_init_single(struct platform_device *dev,
ret = sci_init_clocks(sci_port, &dev->dev);
if (ret < 0)
return ret;
-
- port->dev = &dev->dev;
-
- pm_runtime_enable(&dev->dev);
}
port->type = p->type;
@@ -3087,11 +3101,6 @@ static int sci_init_single(struct platform_device *dev,
return 0;
}
-static void sci_cleanup_single(struct sci_port *port)
-{
- pm_runtime_disable(port->port.dev);
-}
-
#if defined(CONFIG_SERIAL_SH_SCI_CONSOLE) || \
defined(CONFIG_SERIAL_SH_SCI_EARLYCON)
static void serial_console_putchar(struct uart_port *port, unsigned char ch)
@@ -3261,8 +3270,6 @@ static void sci_remove(struct platform_device *dev)
sci_ports_in_use &= ~BIT(port->port.line);
uart_remove_one_port(&sci_uart_driver, &port->port);
- sci_cleanup_single(port);
-
if (port->port.fifosize > 1)
device_remove_file(&dev->dev, &dev_attr_rx_fifo_trigger);
if (type == PORT_SCIFA || type == PORT_SCIFB || type == PORT_HSCIF)
@@ -3384,6 +3391,7 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
}
sp = &sci_ports[id];
+ sp->rstc = rstc;
*dev_id = id;
p->type = SCI_OF_TYPE(data);
@@ -3397,7 +3405,8 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
static int sci_probe_single(struct platform_device *dev,
unsigned int index,
struct plat_sci_port *p,
- struct sci_port *sciport)
+ struct sci_port *sciport,
+ struct resource *sci_res)
{
int ret;
@@ -3426,6 +3435,11 @@ static int sci_probe_single(struct platform_device *dev,
if (ret)
return ret;
+ sciport->port.dev = &dev->dev;
+ ret = devm_pm_runtime_enable(&dev->dev);
+ if (ret)
+ return ret;
+
sciport->gpios = mctrl_gpio_init(&sciport->port, 0);
if (IS_ERR(sciport->gpios))
return PTR_ERR(sciport->gpios);
@@ -3439,13 +3453,31 @@ static int sci_probe_single(struct platform_device *dev,
sciport->port.flags |= UPF_HARD_FLOW;
}
- ret = uart_add_one_port(&sci_uart_driver, &sciport->port);
- if (ret) {
- sci_cleanup_single(sciport);
- return ret;
+ if (sci_uart_earlycon && sci_ports[0].port.mapbase == sci_res->start) {
+ /*
+ * In case:
+ * - this is the earlycon port (mapped on index 0 in sci_ports[]) and
+ * - it now maps to an alias other than zero and
+ * - the earlycon is still alive (e.g., "earlycon keep_bootcon" is
+ * available in bootargs)
+ *
+ * we need to avoid disabling clocks and PM domains through the runtime
+ * PM APIs called in __device_attach(). For this, increment the runtime
+ * PM reference counter (the clocks and PM domains were already enabled
+ * by the bootloader). Otherwise the earlycon may access the HW when it
+ * has no clocks enabled leading to failures (infinite loop in
+ * sci_poll_put_char()).
+ */
+ pm_runtime_get_noresume(&dev->dev);
+
+ /*
+ * Skip cleanup the sci_port[0] in early_console_exit(), this
+ * port is the same as the earlycon one.
+ */
+ sci_uart_earlycon_dev_probing = true;
}
- return 0;
+ return uart_add_one_port(&sci_uart_driver, &sciport->port);
}
static int sci_probe(struct platform_device *dev)
@@ -3503,7 +3535,7 @@ static int sci_probe(struct platform_device *dev)
platform_set_drvdata(dev, sp);
- ret = sci_probe_single(dev, dev_id, p, sp);
+ ret = sci_probe_single(dev, dev_id, p, sp, res);
if (ret)
return ret;
@@ -3532,13 +3564,77 @@ static int sci_probe(struct platform_device *dev)
return 0;
}
+static void sci_console_save(struct sci_port *s)
+{
+ struct sci_suspend_regs *regs = &s->suspend_regs;
+ struct uart_port *port = &s->port;
+
+ if (sci_getreg(port, SCDL)->size)
+ regs->scdl = sci_serial_in(port, SCDL);
+ if (sci_getreg(port, SCCKS)->size)
+ regs->sccks = sci_serial_in(port, SCCKS);
+ if (sci_getreg(port, SCSMR)->size)
+ regs->scsmr = sci_serial_in(port, SCSMR);
+ if (sci_getreg(port, SCSCR)->size)
+ regs->scscr = sci_serial_in(port, SCSCR);
+ if (sci_getreg(port, SCFCR)->size)
+ regs->scfcr = sci_serial_in(port, SCFCR);
+ if (sci_getreg(port, SCSPTR)->size)
+ regs->scsptr = sci_serial_in(port, SCSPTR);
+ if (sci_getreg(port, SCBRR)->size)
+ regs->scbrr = sci_serial_in(port, SCBRR);
+ if (sci_getreg(port, HSSRR)->size)
+ regs->hssrr = sci_serial_in(port, HSSRR);
+ if (sci_getreg(port, SCPCR)->size)
+ regs->scpcr = sci_serial_in(port, SCPCR);
+ if (sci_getreg(port, SCPDR)->size)
+ regs->scpdr = sci_serial_in(port, SCPDR);
+ if (sci_getreg(port, SEMR)->size)
+ regs->semr = sci_serial_in(port, SEMR);
+}
+
+static void sci_console_restore(struct sci_port *s)
+{
+ struct sci_suspend_regs *regs = &s->suspend_regs;
+ struct uart_port *port = &s->port;
+
+ if (sci_getreg(port, SCDL)->size)
+ sci_serial_out(port, SCDL, regs->scdl);
+ if (sci_getreg(port, SCCKS)->size)
+ sci_serial_out(port, SCCKS, regs->sccks);
+ if (sci_getreg(port, SCSMR)->size)
+ sci_serial_out(port, SCSMR, regs->scsmr);
+ if (sci_getreg(port, SCSCR)->size)
+ sci_serial_out(port, SCSCR, regs->scscr);
+ if (sci_getreg(port, SCFCR)->size)
+ sci_serial_out(port, SCFCR, regs->scfcr);
+ if (sci_getreg(port, SCSPTR)->size)
+ sci_serial_out(port, SCSPTR, regs->scsptr);
+ if (sci_getreg(port, SCBRR)->size)
+ sci_serial_out(port, SCBRR, regs->scbrr);
+ if (sci_getreg(port, HSSRR)->size)
+ sci_serial_out(port, HSSRR, regs->hssrr);
+ if (sci_getreg(port, SCPCR)->size)
+ sci_serial_out(port, SCPCR, regs->scpcr);
+ if (sci_getreg(port, SCPDR)->size)
+ sci_serial_out(port, SCPDR, regs->scpdr);
+ if (sci_getreg(port, SEMR)->size)
+ sci_serial_out(port, SEMR, regs->semr);
+}
+
static __maybe_unused int sci_suspend(struct device *dev)
{
struct sci_port *sport = dev_get_drvdata(dev);
- if (sport)
+ if (sport) {
uart_suspend_port(&sci_uart_driver, &sport->port);
+ if (!console_suspend_enabled && uart_console(&sport->port))
+ sci_console_save(sport);
+ else
+ return reset_control_assert(sport->rstc);
+ }
+
return 0;
}
@@ -3546,8 +3642,18 @@ static __maybe_unused int sci_resume(struct device *dev)
{
struct sci_port *sport = dev_get_drvdata(dev);
- if (sport)
+ if (sport) {
+ if (!console_suspend_enabled && uart_console(&sport->port)) {
+ sci_console_restore(sport);
+ } else {
+ int ret = reset_control_deassert(sport->rstc);
+
+ if (ret)
+ return ret;
+ }
+
uart_resume_port(&sci_uart_driver, &sport->port);
+ }
return 0;
}
@@ -3586,6 +3692,22 @@ sh_early_platform_init_buffer("earlyprintk", &sci_driver,
#ifdef CONFIG_SERIAL_SH_SCI_EARLYCON
static struct plat_sci_port port_cfg;
+static int early_console_exit(struct console *co)
+{
+ struct sci_port *sci_port = &sci_ports[0];
+
+ /*
+ * Clean the slot used by earlycon. A new SCI device might
+ * map to this slot.
+ */
+ if (!sci_uart_earlycon_dev_probing) {
+ memset(sci_port, 0, sizeof(*sci_port));
+ sci_uart_earlycon = false;
+ }
+
+ return 0;
+}
+
static int __init early_console_setup(struct earlycon_device *device,
int type)
{
@@ -3603,6 +3725,8 @@ static int __init early_console_setup(struct earlycon_device *device,
SCSCR_RE | SCSCR_TE | port_cfg.scscr);
device->con->write = serial_console_write;
+ device->con->exit = early_console_exit;
+
return 0;
}
static int __init sci_early_console_setup(struct earlycon_device *device,
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-12 08:01:53 +0300