From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx> 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_restore() function was 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@xxxxxxxxxxxxxx> --- The v4 of this patch was part of a series with 4 patches. As the rest of the patches were applied I dropped the cover letter. The v4 cover letter is located here: https://lore.kernel.org/all/20250120130936.1080069-1-claudiu.beznea.uj@xxxxxxxxxxxxxx Changes in v5: - fixed typo in patch description - adjusted the patch description to reflect the new patch content - added struct sci_suspend_regs and dropped the suspend_cacheable flag introduced previously in struct plat_sci_reg; along with it the updates in sci_port_params[] were also dropped; also, the function (now sci_console_save_restore()) that saves and restores the registers content was adjusted accordingly - s/sci_console_setup/sci_console_save_restore/g Changes in v4: - none Changes in v3: - none Changes in v2: - rebased on top of the update version of patch 2/8 from this series drivers/tty/serial/sh-sci.c | 55 +++++++++++++++++++++++++++++++++++-- 1 file changed, 53 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index b1ea48f38248..03349bc31080 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; @@ -3374,6 +3386,7 @@ 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); @@ -3546,13 +3559,41 @@ static int sci_probe(struct platform_device *dev) return 0; } +static void sci_console_save_restore(struct sci_port *s, bool save) +{ + struct sci_suspend_regs *regs = &s->suspend_regs; + struct uart_port *port = &s->port; + + if (save) { + regs->scsmr = sci_serial_in(port, SCSMR); + regs->scscr = sci_serial_in(port, SCSCR); + regs->scfcr = sci_serial_in(port, SCFCR); + regs->scsptr = sci_serial_in(port, SCSPTR); + regs->scbrr = sci_serial_in(port, SCBRR); + regs->semr = sci_serial_in(port, SEMR); + } else { + sci_serial_out(port, SCSMR, regs->scsmr); + sci_serial_out(port, SCSCR, regs->scscr); + sci_serial_out(port, SCFCR, regs->scfcr); + sci_serial_out(port, SCSPTR, regs->scsptr); + sci_serial_out(port, SCBRR, regs->scbrr); + 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_restore(sport, true); + else + return reset_control_assert(sport->rstc); + } + return 0; } @@ -3560,8 +3601,18 @@ 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_save_restore(sport, false); + } else { + int ret = reset_control_deassert(sport->rstc); + + if (ret) + return ret; + } + uart_resume_port(&sci_uart_driver, &sport->port); + } return 0; } -- 2.43.0
