| Message ID | 1582707225-26815-1-git-send-email-changqi.hu@mediatek.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | e32a83c70cf987df8937760fa263296acf84f963 |
| Headers | show |
| Series | [v4] serial: 8250-mtk: modify mtk uart power and clock management | expand |
On Wed, Feb 26, 2020 at 4:54 PM Changqi Hu <changqi.hu@mediatek.com> wrote: > > MTK uart design no need to control uart clock, > so we just control bus clock in runtime function. > Add uart clock used count to avoid repeatedly switching the clock. This patch does a lot more than that: - Adds a busy loop in mtk8250_runtime_suspend - Changes how you do pm_runtime stuff. These probably need to be split to different patches, and can you please describe why you are making those changes in the commit message? > Signed-off-by: Changqi Hu <changqi.hu@mediatek.com> > --- > > Changes in v4: > Modify commit-message > > Changes in v3: > Merge patch v1 and v2 together. > > Changes in v2: > Enable uart bus clock when probe and resume base on v1 patch, > but miss v1 patch itself. > > drivers/tty/serial/8250/8250_mtk.c | 50 ++++++++++++++++++++++++-------------- > 1 file changed, 32 insertions(+), 18 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c > index 4d067f5..f839380 100644 > --- a/drivers/tty/serial/8250/8250_mtk.c > +++ b/drivers/tty/serial/8250/8250_mtk.c > @@ -32,6 +32,7 @@ > #define MTK_UART_RXTRI_AD 0x14 /* RX Trigger address */ > #define MTK_UART_FRACDIV_L 0x15 /* Fractional divider LSB address */ > #define MTK_UART_FRACDIV_M 0x16 /* Fractional divider MSB address */ > +#define MTK_UART_DEBUG0 0x18 > #define MTK_UART_IER_XOFFI 0x20 /* Enable XOFF character interrupt */ > #define MTK_UART_IER_RTSI 0x40 /* Enable RTS Modem status interrupt */ > #define MTK_UART_IER_CTSI 0x80 /* Enable CTS Modem status interrupt */ > @@ -388,9 +389,18 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, > static int __maybe_unused mtk8250_runtime_suspend(struct device *dev) > { > struct mtk8250_data *data = dev_get_drvdata(dev); > + struct uart_8250_port *up = serial8250_get_port(data->line); > > - clk_disable_unprepare(data->uart_clk); > - clk_disable_unprepare(data->bus_clk); > + /* wait until UART in idle status */ > + while > + (serial_in(up, MTK_UART_DEBUG0)); No timeout? > + > + if (data->clk_count == 0U) { > + dev_dbg(dev, "%s clock count is 0\n", __func__); > + } else { > + clk_disable_unprepare(data->bus_clk); > + data->clk_count--; > + } The clock core already does reference counting for you, so I don't think you need this. https://elixir.bootlin.com/linux/latest/source/drivers/clk/clk.c#L1004 > > return 0; > } > @@ -400,16 +410,16 @@ static int __maybe_unused mtk8250_runtime_resume(struct device *dev) > struct mtk8250_data *data = dev_get_drvdata(dev); > int err; > > - err = clk_prepare_enable(data->uart_clk); > - if (err) { > - dev_warn(dev, "Can't enable clock\n"); > - return err; > - } > - > - err = clk_prepare_enable(data->bus_clk); > - if (err) { > - dev_warn(dev, "Can't enable bus clock\n"); > - return err; > + if (data->clk_count > 0U) { > + dev_dbg(dev, "%s clock count is %d\n", __func__, > + data->clk_count); > + } else { > + err = clk_prepare_enable(data->bus_clk); > + if (err) { > + dev_warn(dev, "Can't enable bus clock\n"); > + return err; > + } > + data->clk_count++; > } > > return 0; > @@ -419,12 +429,14 @@ static void > mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old) > { > if (!state) > - pm_runtime_get_sync(port->dev); > + if (!mtk8250_runtime_resume(port->dev)) > + pm_runtime_get_sync(port->dev); > > serial8250_do_pm(port, state, old); > > if (state) > - pm_runtime_put_sync_suspend(port->dev); > + if (!pm_runtime_put_sync_suspend(port->dev)) > + mtk8250_runtime_suspend(port->dev); > } > > #ifdef CONFIG_SERIAL_8250_DMA > @@ -501,6 +513,8 @@ static int mtk8250_probe(struct platform_device *pdev) > if (!data) > return -ENOMEM; > > + data->clk_count = 0; > + > if (pdev->dev.of_node) { > err = mtk8250_probe_of(pdev, &uart.port, data); > if (err) > @@ -533,6 +547,7 @@ static int mtk8250_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, data); > > + pm_runtime_enable(&pdev->dev); > err = mtk8250_runtime_resume(&pdev->dev); > if (err) > return err; > @@ -541,9 +556,6 @@ static int mtk8250_probe(struct platform_device *pdev) > if (data->line < 0) > return data->line; > > - pm_runtime_set_active(&pdev->dev); > - pm_runtime_enable(&pdev->dev); > - > data->rx_wakeup_irq = platform_get_irq_optional(pdev, 1); > > return 0; > @@ -556,11 +568,13 @@ static int mtk8250_remove(struct platform_device *pdev) > pm_runtime_get_sync(&pdev->dev); > > serial8250_unregister_port(data->line); > - mtk8250_runtime_suspend(&pdev->dev); > > pm_runtime_disable(&pdev->dev); > pm_runtime_put_noidle(&pdev->dev); > > + if (!pm_runtime_status_suspended(&pdev->dev)) > + mtk8250_runtime_suspend(&pdev->dev); > + > return 0; > } > > -- > 2.6.4
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c index 4d067f5..f839380 100644 --- a/drivers/tty/serial/8250/8250_mtk.c +++ b/drivers/tty/serial/8250/8250_mtk.c @@ -32,6 +32,7 @@ #define MTK_UART_RXTRI_AD 0x14 /* RX Trigger address */ #define MTK_UART_FRACDIV_L 0x15 /* Fractional divider LSB address */ #define MTK_UART_FRACDIV_M 0x16 /* Fractional divider MSB address */ +#define MTK_UART_DEBUG0 0x18 #define MTK_UART_IER_XOFFI 0x20 /* Enable XOFF character interrupt */ #define MTK_UART_IER_RTSI 0x40 /* Enable RTS Modem status interrupt */ #define MTK_UART_IER_CTSI 0x80 /* Enable CTS Modem status interrupt */ @@ -388,9 +389,18 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios, static int __maybe_unused mtk8250_runtime_suspend(struct device *dev) { struct mtk8250_data *data = dev_get_drvdata(dev); + struct uart_8250_port *up = serial8250_get_port(data->line); - clk_disable_unprepare(data->uart_clk); - clk_disable_unprepare(data->bus_clk); + /* wait until UART in idle status */ + while + (serial_in(up, MTK_UART_DEBUG0)); + + if (data->clk_count == 0U) { + dev_dbg(dev, "%s clock count is 0\n", __func__); + } else { + clk_disable_unprepare(data->bus_clk); + data->clk_count--; + } return 0; } @@ -400,16 +410,16 @@ static int __maybe_unused mtk8250_runtime_resume(struct device *dev) struct mtk8250_data *data = dev_get_drvdata(dev); int err; - err = clk_prepare_enable(data->uart_clk); - if (err) { - dev_warn(dev, "Can't enable clock\n"); - return err; - } - - err = clk_prepare_enable(data->bus_clk); - if (err) { - dev_warn(dev, "Can't enable bus clock\n"); - return err; + if (data->clk_count > 0U) { + dev_dbg(dev, "%s clock count is %d\n", __func__, + data->clk_count); + } else { + err = clk_prepare_enable(data->bus_clk); + if (err) { + dev_warn(dev, "Can't enable bus clock\n"); + return err; + } + data->clk_count++; } return 0; @@ -419,12 +429,14 @@ static void mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old) { if (!state) - pm_runtime_get_sync(port->dev); + if (!mtk8250_runtime_resume(port->dev)) + pm_runtime_get_sync(port->dev); serial8250_do_pm(port, state, old); if (state) - pm_runtime_put_sync_suspend(port->dev); + if (!pm_runtime_put_sync_suspend(port->dev)) + mtk8250_runtime_suspend(port->dev); } #ifdef CONFIG_SERIAL_8250_DMA @@ -501,6 +513,8 @@ static int mtk8250_probe(struct platform_device *pdev) if (!data) return -ENOMEM; + data->clk_count = 0; + if (pdev->dev.of_node) { err = mtk8250_probe_of(pdev, &uart.port, data); if (err) @@ -533,6 +547,7 @@ static int mtk8250_probe(struct platform_device *pdev) platform_set_drvdata(pdev, data); + pm_runtime_enable(&pdev->dev); err = mtk8250_runtime_resume(&pdev->dev); if (err) return err; @@ -541,9 +556,6 @@ static int mtk8250_probe(struct platform_device *pdev) if (data->line < 0) return data->line; - pm_runtime_set_active(&pdev->dev); - pm_runtime_enable(&pdev->dev); - data->rx_wakeup_irq = platform_get_irq_optional(pdev, 1); return 0; @@ -556,11 +568,13 @@ static int mtk8250_remove(struct platform_device *pdev) pm_runtime_get_sync(&pdev->dev); serial8250_unregister_port(data->line); - mtk8250_runtime_suspend(&pdev->dev); pm_runtime_disable(&pdev->dev); pm_runtime_put_noidle(&pdev->dev); + if (!pm_runtime_status_suspended(&pdev->dev)) + mtk8250_runtime_suspend(&pdev->dev); + return 0; }
MTK uart design no need to control uart clock, so we just control bus clock in runtime function. Add uart clock used count to avoid repeatedly switching the clock. Signed-off-by: Changqi Hu <changqi.hu@mediatek.com> --- Changes in v4: Modify commit-message Changes in v3: Merge patch v1 and v2 together. Changes in v2: Enable uart bus clock when probe and resume base on v1 patch, but miss v1 patch itself. drivers/tty/serial/8250/8250_mtk.c | 50 ++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 18 deletions(-)