From: Claudiu Beznea claudiu.beznea.uj@bp.renesas.com
[ Upstream commit 22a6984c5b5df8eab864d7f3e8b94d5a554d31ab ]
The Renesas RZ/G3S supports a power saving mode where power to most of the SoC components is turned off. When returning from this power saving mode, SoC components need to be re-configured.
The SCIFs on the Renesas RZ/G3S need to be re-configured as well when returning from this power saving mode. The sh-sci code already configures the SCIF clocks, power domain and registers by calling uart_resume_port() in sci_resume(). On suspend path the SCIF UART ports are suspended accordingly (by calling uart_suspend_port() in sci_suspend()). The only missing setting is the reset signal. For this assert/de-assert the reset signal on driver suspend/resume.
In case the no_console_suspend is specified by the user, the registers need to be saved on suspend path and restore on resume path. To do this the sci_console_save()/sci_console_restore() functions were added. There is no need to cache/restore the status or FIFO registers. Only the control registers. The registers that will be saved/restored on suspend/resume are specified by the struct sci_suspend_regs data structure.
Signed-off-by: Claudiu Beznea claudiu.beznea.uj@bp.renesas.com Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be Link: https://lore.kernel.org/r/20250207113313.545432-1-claudiu.beznea.uj@bp.renes... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/sh-sci.c | 71 +++++++++++++++++++++++++++++++++++-- 1 file changed, 69 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 80efe3b0ed0c3..779074b1c2be4 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -104,6 +104,15 @@ struct plat_sci_reg { u8 offset, size; };
+struct sci_suspend_regs { + u16 scsmr; + u16 scscr; + u16 scfcr; + u16 scsptr; + u8 scbrr; + u8 semr; +}; + struct sci_port_params { const struct plat_sci_reg regs[SCIx_NR_REGS]; unsigned int fifosize; @@ -134,6 +143,8 @@ 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 +164,7 @@ 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; @@ -3384,6 +3396,7 @@ 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); @@ -3532,13 +3545,57 @@ 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, 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, 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, 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, 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 +3603,18 @@ 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; }