[PATCH V2 4/6] tty: serial: meson: The UART baud rate calculation is described using the common clock code. Also added S4 chip uart Compatible.
Yu Tu
yu.tu at amlogic.com
Thu Dec 30 01:35:33 PST 2021
Hi Vyacheslav,
Thank you very much for your reply.
On 2021/12/30 3:07, Vyacheslav wrote:
> [ EXTERNAL EMAIL ]
>
>
>
> 29.12.2021 16:53, Yu Tu пишет:
>> Using the common Clock code to describe the UART baud rate clock makes
>> it easier for the UART driver to be compatible with the baud rate
>> requirements of the UART IP on different meson chips
>>
>> Signed-off-by: Yu Tu <yu.tu at amlogic.com>
>> ---
>> drivers/tty/serial/Kconfig | 1 +
>> drivers/tty/serial/meson_uart.c | 303 ++++++++++++++++++++++++++------
>> 2 files changed, 249 insertions(+), 55 deletions(-)
>>
>> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
>> index 780908d43557..32e238173036 100644
>> --- a/drivers/tty/serial/Kconfig
>> +++ b/drivers/tty/serial/Kconfig
>> @@ -198,6 +198,7 @@ config SERIAL_KGDB_NMI
>> config SERIAL_MESON
>> tristate "Meson serial port support"
>> depends on ARCH_MESON
>> + depends on COMMON_CLK
>> select SERIAL_CORE
>> help
>> This enables the driver for the on-chip UARTs of the Amlogic
>> diff --git a/drivers/tty/serial/meson_uart.c
>> b/drivers/tty/serial/meson_uart.c
>> index 99efe62a1507..9b07e3534969 100644
>> --- a/drivers/tty/serial/meson_uart.c
>> +++ b/drivers/tty/serial/meson_uart.c
>> @@ -6,6 +6,7 @@
>> */
>> #include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> #include <linux/console.h>
>> #include <linux/delay.h>
>> #include <linux/init.h>
>> @@ -65,9 +66,7 @@
>> #define AML_UART_RECV_IRQ(c) ((c) & 0xff)
>> /* AML_UART_REG5 bits */
>> -#define AML_UART_BAUD_MASK 0x7fffff
>> #define AML_UART_BAUD_USE BIT(23)
>> -#define AML_UART_BAUD_XTAL BIT(24)
>> #define AML_UART_PORT_NUM 12
>> #define AML_UART_PORT_OFFSET 6
>> @@ -76,6 +75,21 @@
>> #define AML_UART_POLL_USEC 5
>> #define AML_UART_TIMEOUT_USEC 10000
>> +struct meson_uart_data {
>> + struct uart_port port;
>> + struct clk *pclk;
>> + struct clk *baud_clk;
>> + struct clk_divider baud_div;
>> + struct clk_mux use_xtal_mux;
>> + struct clk_mux xtal_clk_sel_mux;
>> + struct clk_mux xtal2_clk_sel_mux;
>> + struct clk_fixed_factor xtal_div2;
>> + struct clk_fixed_factor xtal_div3;
>> + struct clk_fixed_factor clk81_div4;
>> + bool no_clk81_input;
>> + bool has_xtal_clk_sel;
>> +};
>> +
>> static struct uart_driver meson_uart_driver;
>> static struct uart_port *meson_ports[AML_UART_PORT_NUM];
>> @@ -270,14 +284,11 @@ static void meson_uart_reset(struct uart_port
>> *port)
>> static int meson_uart_startup(struct uart_port *port)
>> {
>> u32 val;
>> - int ret = 0;
>> + int ret;
>> - val = readl(port->membase + AML_UART_CONTROL);
>> - val |= AML_UART_CLEAR_ERR;
>> - writel(val, port->membase + AML_UART_CONTROL);
>> - val &= ~AML_UART_CLEAR_ERR;
>> - writel(val, port->membase + AML_UART_CONTROL);
>> + meson_uart_reset(port);
>> + val = readl(port->membase + AML_UART_CONTROL);
>> val |= (AML_UART_RX_EN | AML_UART_TX_EN);
>> writel(val, port->membase + AML_UART_CONTROL);
>> @@ -295,19 +306,17 @@ static int meson_uart_startup(struct uart_port
>> *port)
>> static void meson_uart_change_speed(struct uart_port *port, unsigned
>> long baud)
>> {
>> + struct meson_uart_data *private_data = port->private_data;
>> u32 val;
>> while (!meson_uart_tx_empty(port))
>> cpu_relax();
>> - if (port->uartclk == 24000000) {
>> - val = ((port->uartclk / 3) / baud) - 1;
>> - val |= AML_UART_BAUD_XTAL;
>> - } else {
>> - val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1;
>> - }
>> + val = readl(port->membase + AML_UART_REG5);
>> val |= AML_UART_BAUD_USE;
>> writel(val, port->membase + AML_UART_REG5);
>> +
>> + clk_set_rate(private_data->baud_clk, baud);
>> }
>> static void meson_uart_set_termios(struct uart_port *port,
>> @@ -397,11 +406,27 @@ static int meson_uart_verify_port(struct
>> uart_port *port,
>> static void meson_uart_release_port(struct uart_port *port)
>> {
>> - /* nothing to do */
>> + struct meson_uart_data *private_data = port->private_data;
>> +
>> + clk_disable_unprepare(private_data->baud_clk);
>> + clk_disable_unprepare(private_data->pclk);
>> }
>> static int meson_uart_request_port(struct uart_port *port)
>> {
>> + struct meson_uart_data *private_data = port->private_data;
>> + int ret;
>> +
>> + ret = clk_prepare_enable(private_data->pclk);
>> + if (ret)
>> + return ret;
>> +
>> + ret = clk_prepare_enable(private_data->baud_clk);
>> + if (ret) {
>> + clk_disable_unprepare(private_data->pclk);
>> + return ret;
>> + }
>> +
>> return 0;
>> }
>> @@ -629,56 +654,175 @@ static struct uart_driver meson_uart_driver = {
>> .cons = MESON_SERIAL_CONSOLE,
>> };
>> -static inline struct clk *meson_uart_probe_clock(struct device *dev,
>> - const char *id)
>> +static int meson_uart_register_clk(struct uart_port *port,
>> + const char *name_suffix,
>> + const struct clk_parent_data *parent_data,
>> + unsigned int num_parents,
>> + const struct clk_ops *ops,
>> + struct clk_hw *hw)
>> {
>> - struct clk *clk = NULL;
>> + struct clk_init_data init = { };
>> + char clk_name[32];
>> int ret;
>> - clk = devm_clk_get(dev, id);
>> - if (IS_ERR(clk))
>> - return clk;
>> + snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev),
>> + name_suffix);
>> - ret = clk_prepare_enable(clk);
>> - if (ret) {
>> - dev_err(dev, "couldn't enable clk\n");
>> - return ERR_PTR(ret);
>> - }
>> + init.name = clk_name;
>> + init.ops = ops;
>> + init.flags = CLK_SET_RATE_PARENT;
>> + init.parent_data = parent_data;
>> + init.num_parents = num_parents;
>> +
>> + hw->init = &init;
>> - devm_add_action_or_reset(dev,
>> - (void(*)(void *))clk_disable_unprepare,
>> - clk);
>> + ret = devm_clk_hw_register(port->dev, hw);
>> + if (ret)
>> + return dev_err_probe(port->dev, ret,
>> + "Failed to register the '%s' clock\n",
>> + clk_name);
>> - return clk;
>> + return ret;
>> }
>> -static int meson_uart_probe_clocks(struct platform_device *pdev,
>> - struct uart_port *port)
>> -{
>> - struct clk *clk_xtal = NULL;
>> - struct clk *clk_pclk = NULL;
>> - struct clk *clk_baud = NULL;
>> +static int meson_uart_probe_clocks(struct uart_port *port,
>> + bool register_clk81_div4)
>> +{
>> + struct meson_uart_data *private_data = port->private_data;
>> + struct clk_parent_data use_xtal_mux_parents[2] = {
>> + { .index = -1, },
>> + { .index = -1, },
>> + };
>> + struct clk_parent_data xtal_clk_sel_mux_parents[2] = { };
>> + struct clk_parent_data xtal2_clk_sel_mux_parents[2] = { };
>> + struct clk_parent_data xtal_div_parent = { .fw_name = "xtal", };
>> + struct clk_parent_data clk81_div_parent = { .fw_name = "baud", };
>> + struct clk_parent_data baud_div_parent = { };
>> + struct clk *clk_baud, *clk_xtal;
>> + int ret;
>> - clk_pclk = meson_uart_probe_clock(&pdev->dev, "pclk");
>> - if (IS_ERR(clk_pclk))
>> - return PTR_ERR(clk_pclk);
>> + private_data->pclk = devm_clk_get(port->dev, "pclk");
>> + if (IS_ERR(private_data->pclk))
>> + return dev_err_probe(port->dev, PTR_ERR(private_data->pclk),
>> + "Failed to get the 'pclk' clock\n");
>> +
>> + clk_baud = devm_clk_get(port->dev, "baud");
>> + if (IS_ERR(clk_baud))
>> + return dev_err_probe(port->dev, PTR_ERR(clk_baud),
>> + "Failed to get the 'baud' clock\n");
>> - clk_xtal = meson_uart_probe_clock(&pdev->dev, "xtal");
>> + clk_xtal = devm_clk_get(port->dev, "xtal");
>> if (IS_ERR(clk_xtal))
>> - return PTR_ERR(clk_xtal);
>> + return dev_err_probe(port->dev, PTR_ERR(clk_xtal),
>> + "Failed to get the 'xtal' clock\n");
>> +
>> + private_data->xtal_div3.mult = 1;
>> + private_data->xtal_div3.div = 3;
>> + ret = meson_uart_register_clk(port, "xtal_div3", &xtal_div_parent,
>> + 1, &clk_fixed_factor_ops,
>> + &private_data->xtal_div3.hw);
>> + if (ret)
>> + return ret;
>> - clk_baud = meson_uart_probe_clock(&pdev->dev, "baud");
>> - if (IS_ERR(clk_baud))
>> - return PTR_ERR(clk_baud);
>> + if (register_clk81_div4) {
>> + private_data->clk81_div4.mult = 1;
>> + private_data->clk81_div4.div = 4;
>> + ret = meson_uart_register_clk(port, "clk81_div4",
>> + &clk81_div_parent, 1,
>> + &clk_fixed_factor_ops,
>> + &private_data->clk81_div4.hw);
>> + if (ret)
>> + return ret;
>> +
>> + use_xtal_mux_parents[0].hw = &private_data->clk81_div4.hw;
>> + }
>> - port->uartclk = clk_get_rate(clk_baud);
>> + if (private_data->has_xtal_clk_sel) {
>> + private_data->xtal_div2.mult = 1;
>> + private_data->xtal_div2.div = 2;
>> + ret = meson_uart_register_clk(port, "xtal_div2",
>> + &xtal_div_parent, 1,
>> + &clk_fixed_factor_ops,
>> + &private_data->xtal_div2.hw);
>> + if (ret)
>> + return ret;
>> +
>> + xtal_clk_sel_mux_parents[0].hw = &private_data->xtal_div3.hw;
>> + xtal_clk_sel_mux_parents[1].fw_name = "xtal";
>> +
>> + private_data->xtal_clk_sel_mux.reg = port->membase +
>> AML_UART_REG5;
>> + private_data->xtal_clk_sel_mux.mask = 0x1;
>> + private_data->xtal_clk_sel_mux.shift = 26;
>> + private_data->xtal_clk_sel_mux.flags = CLK_MUX_ROUND_CLOSEST;
>> + ret = meson_uart_register_clk(port, "xtal_clk_sel",
>> + xtal_clk_sel_mux_parents,
>> + ARRAY_SIZE(xtal_clk_sel_mux_parents),
>> + &clk_mux_ops,
>> + &private_data->xtal_clk_sel_mux.hw);
>> + if (ret)
>> + return ret;
>> +
>> + xtal2_clk_sel_mux_parents[0].hw =
>> &private_data->xtal_clk_sel_mux.hw;
>> + xtal2_clk_sel_mux_parents[1].hw = &private_data->xtal_div2.hw;
>> +
>> + private_data->xtal2_clk_sel_mux.reg = port->membase +
>> AML_UART_REG5;
>> + private_data->xtal2_clk_sel_mux.mask = 0x1;
>> + private_data->xtal2_clk_sel_mux.shift = 27;
>> + private_data->xtal2_clk_sel_mux.flags = CLK_MUX_ROUND_CLOSEST;
>> + ret = meson_uart_register_clk(port, "xtal2_clk_sel",
>> + xtal2_clk_sel_mux_parents,
>> + ARRAY_SIZE(xtal2_clk_sel_mux_parents),
>> + &clk_mux_ops,
>> + &private_data->xtal2_clk_sel_mux.hw);
>> + if (ret)
>> + return ret;
>> +
>> + use_xtal_mux_parents[1].hw =
>> &private_data->xtal2_clk_sel_mux.hw;
>> + } else {
>> + use_xtal_mux_parents[1].hw = &private_data->xtal_div3.hw;
>> + }
>> +
>> + private_data->use_xtal_mux.reg = port->membase + AML_UART_REG5;
>> + private_data->use_xtal_mux.mask = 0x1;
>> + private_data->use_xtal_mux.shift = 24;
>> + private_data->use_xtal_mux.flags = CLK_MUX_ROUND_CLOSEST;
>> + ret = meson_uart_register_clk(port, "use_xtal",
>> use_xtal_mux_parents,
>> + ARRAY_SIZE(use_xtal_mux_parents),
>> + &clk_mux_ops,
>> + &private_data->use_xtal_mux.hw);
>> + if (ret)
>> + return ret;
>> +
>> + baud_div_parent.hw = &private_data->use_xtal_mux.hw;
>> +
>> + private_data->baud_div.reg = port->membase + AML_UART_REG5;
>> + private_data->baud_div.shift = 0;
>> + private_data->baud_div.width = 23;
>> + private_data->baud_div.flags = CLK_DIVIDER_ROUND_CLOSEST;
>> + ret = meson_uart_register_clk(port, "baud_div",
>> + &baud_div_parent, 1,
>> + &clk_divider_ops,
>> + &private_data->baud_div.hw);
>> + if (ret)
>> + return ret;
>> +
>> + private_data->baud_clk = devm_clk_hw_get_clk(port->dev,
>> + &private_data->baud_div.hw,
>> + "baud_rate");
>> + if (IS_ERR(private_data->baud_clk))
>> + return dev_err_probe(port->dev,
>> + PTR_ERR(private_data->baud_clk),
>> + "Failed to request the 'baud_rate' clock\n");
>> return 0;
>> }
>> static int meson_uart_probe(struct platform_device *pdev)
>> {
>> + struct meson_uart_data *private_data;
>> struct resource *res_mem, *res_irq;
>> + struct clk *clk_baud, *clk_xtal;
>> + bool register_clk81_div4;
>> struct uart_port *port;
>> int ret = 0;
>> int id = -1;
>> @@ -711,18 +855,37 @@ static int meson_uart_probe(struct
>> platform_device *pdev)
>> return -EBUSY;
>> }
>> - port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port),
>> GFP_KERNEL);
>> - if (!port)
>> + private_data = devm_kzalloc(&pdev->dev, sizeof(*private_data),
>> + GFP_KERNEL);
>> + if (!private_data)
>> return -ENOMEM;
>> + if (device_get_match_data(&pdev->dev))
>> + private_data->has_xtal_clk_sel = true;
>> +
>> + private_data->pclk = devm_clk_get(&pdev->dev, "pclk");
>> + if (IS_ERR(private_data->pclk))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(private_data->pclk),
>> + "Failed to get the 'pclk' clock\n");
>> +
>> + clk_baud = devm_clk_get(&pdev->dev, "baud");
>> + if (IS_ERR(clk_baud))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(clk_baud),
>> + "Failed to get the 'baud' clock\n");
>> +
>> + clk_xtal = devm_clk_get(&pdev->dev, "xtal");
>> + if (IS_ERR(clk_xtal))
>> + return dev_err_probe(&pdev->dev, PTR_ERR(clk_xtal),
>> + "Failed to get the 'xtal' clock\n");
>> +
>> + register_clk81_div4 = clk_get_rate(clk_xtal) !=
>> clk_get_rate(clk_baud);
>> +
>> + port = &private_data->port;
>> +
>> port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
>> if (IS_ERR(port->membase))
>> return PTR_ERR(port->membase);
>> - ret = meson_uart_probe_clocks(pdev, port);
>> - if (ret)
>> - return ret;
>> -
>> port->iotype = UPIO_MEM;
>> port->mapbase = res_mem->start;
>> port->mapsize = resource_size(res_mem);
>> @@ -735,6 +898,12 @@ static int meson_uart_probe(struct
>> platform_device *pdev)
>> port->x_char = 0;
>> port->ops = &meson_uart_ops;
>> port->fifosize = 64;
>> + port->uartclk = clk_get_rate(clk_baud);
>> + port->private_data = private_data;
>> +
>> + ret = meson_uart_probe_clocks(port, register_clk81_div4);
>> + if (ret)
>> + return ret;
>> meson_ports[pdev->id] = port;
>> platform_set_drvdata(pdev, port);
>> @@ -761,10 +930,34 @@ static int meson_uart_remove(struct
>> platform_device *pdev)
>> }
>> static const struct of_device_id meson_uart_dt_match[] = {
>> - { .compatible = "amlogic,meson6-uart" },
>> - { .compatible = "amlogic,meson8-uart" },
>> - { .compatible = "amlogic,meson8b-uart" },
>> - { .compatible = "amlogic,meson-gx-uart" },
>
> You can't drop used item without patch for dts files.
>
> arch/arm64/boot/dts/amlogic$ grep amlogic,meson-gx-uart *|wc -l
> 16
> You're right. I was thoughtless. I'm going to add this delete. Delete
after changing DTS.
>> + {
>> + .compatible = "amlogic,meson6-uart",
>> + .data = (void *)false,
>> + },
>> + {
>> + .compatible = "amlogic,meson8-uart",
>> + .data = (void *)false,
>> + },
>> + {
>> + .compatible = "amlogic,meson8b-uart",
>> + .data = (void *)false,
>> + },
>> + {
>> + .compatible = "amlogic,meson-gxbb-uart",
>> + .data = (void *)false,
>> + },
>> + {
>> + .compatible = "amlogic,meson-gxl-uart",
>> + .data = (void *)true,
>> + },
>> + {
>> + .compatible = "amlogic,meson-g12a-uart",
>> + .data = (void *)true,
>> + },
>> + {
>> + .compatible = "amlogic,meson-s4-uart",
>> + .data = (void *)true,
>> + },
>> { /* sentinel */ },
>> };
>> MODULE_DEVICE_TABLE(of, meson_uart_dt_match);
>
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