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([82.78.167.28]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5cee6afe528sm2697984a12.55.2024.11.06.04.01.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Nov 2024 04:01:36 -0800 (PST) From: Claudiu X-Google-Original-From: Claudiu To: geert+renesas@glider.be, magnus.damm@gmail.com, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, mturquette@baylibre.com, sboyd@kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, p.zabel@pengutronix.de, lethal@linux-sh.org, g.liakhovetski@gmx.de, ysato@users.sourceforge.jp, ulrich.hecht+renesas@gmail.com Cc: claudiu.beznea@tuxon.dev, linux-renesas-soc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-serial@vger.kernel.org, Claudiu Beznea Subject: [PATCH 4/9] serial: sh-sci: Update the suspend/resume support Date: Wed, 6 Nov 2024 14:01:13 +0200 Message-Id: <20241106120118.1719888-5-claudiu.beznea.uj@bp.renesas.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20241106120118.1719888-1-claudiu.beznea.uj@bp.renesas.com> References: <20241106120118.1719888-1-claudiu.beznea.uj@bp.renesas.com> Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Claudiu Beznea 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_setup() function was added. There is no need to cache/restore the status or FIFO registers. Only the control registers. To differentiate b/w these, the struct sci_port_params::regs was updated with a new member that specifies if the register needs to be chached on suspend. Only the RZ_SCIFA instances were updated with this new support as the hardware for the rest of variants was missing for testing. Signed-off-by: Claudiu Beznea --- drivers/tty/serial/sh-sci.c | 53 ++++++++++++++++++++++++++++++------- 1 file changed, 44 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 2f8188bdb251..9548b8e97b8f 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -101,7 +101,7 @@ enum SCI_CLKS { if ((_port)->sampling_rate_mask & SCI_SR((_sr))) struct plat_sci_reg { - u8 offset, size; + u8 offset, size, suspend_cacheable; }; struct sci_port_params { @@ -134,6 +134,8 @@ 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; @@ -154,6 +156,7 @@ struct sci_port { struct timer_list rx_fifo_timer; int rx_fifo_timeout; atomic_t first_time_tx; + unsigned int console_cached_regs[SCIx_NR_REGS]; u16 hscif_tot; bool has_rtscts; @@ -298,17 +301,17 @@ static const struct sci_port_params sci_port_params[SCIx_NR_REGTYPES] = { */ [SCIx_RZ_SCIFA_REGTYPE] = { .regs = { - [SCSMR] = { 0x00, 16 }, - [SCBRR] = { 0x02, 8 }, - [SCSCR] = { 0x04, 16 }, + [SCSMR] = { 0x00, 16, 1 }, + [SCBRR] = { 0x02, 8, 1 }, + [SCSCR] = { 0x04, 16, 1 }, [SCxTDR] = { 0x06, 8 }, [SCxSR] = { 0x08, 16 }, [SCxRDR] = { 0x0A, 8 }, - [SCFCR] = { 0x0C, 16 }, + [SCFCR] = { 0x0C, 16, 1 }, [SCFDR] = { 0x0E, 16 }, - [SCSPTR] = { 0x10, 16 }, + [SCSPTR] = { 0x10, 16, 1 }, [SCLSR] = { 0x12, 16 }, - [SEMR] = { 0x14, 8 }, + [SEMR] = { 0x14, 8, 1 }, }, .fifosize = 16, .overrun_reg = SCLSR, @@ -3365,6 +3368,7 @@ 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); @@ -3492,13 +3496,34 @@ static int sci_probe(struct platform_device *dev) return 0; } +static void sci_console_setup(struct sci_port *s, bool save) +{ + for (u16 i = 0; i < SCIx_NR_REGS; i++) { + struct uart_port *port = &s->port; + + if (!s->params->regs[i].suspend_cacheable) + continue; + + if (save) + s->console_cached_regs[i] = sci_serial_in(port, i); + else + sci_serial_out(port, i, s->console_cached_regs[i]); + } +} + 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_setup(sport, true); + else + return reset_control_assert(sport->rstc); + } + return 0; } @@ -3506,8 +3531,18 @@ 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_setup(sport, false); + } else { + int ret = reset_control_deassert(sport->rstc); + + if (ret) + return ret; + } + uart_resume_port(&sci_uart_driver, &sport->port); + } return 0; }