Revert "tty: serial: meson: *"

This reverts the following commits:

31979060 tty: serial: meson: Fix the compile link error reported by kernel test robot
5427c352 tty: serial: meson: Added S4 SOC compatibility
19b2ba0b tty: serial: meson: The system stuck when you run the stty command on the console to change the baud rate
e5fc2b99 tty: serial: meson: Make some bit of the REG5 register writable
44023b8e tty: serial: meson: Describes the calculation of the UART baud rate clock using a clock frame
6436dd8f tty: serial: meson: Use devm_ioremap_resource to get register mapped memory
841f913e tty: serial: meson: Move request the register region to probe

They seem to cause lots of problems with existing hardware platforms,
and caused build issues, so revert the whole series all at once.

Link: https://lore.kernel.org/r/849a95fd-ae81-9a3b-0c06-dd7826af9eb2@baylibre.com
Link: https://lore.kernel.org/all/20220225073922.3947-1-yu.tu@amlogic.com/Reported-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reported-by: NJerome Brunet <jbrunet@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Yu Tu <yu.tu@amlogic.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -200,7 +200,6 @@ config SERIAL_KGDB_NMI
 config SERIAL_MESON
 	tristate "Meson serial port support"
 	depends on ARCH_MESON || COMPILE_TEST
-	depends on COMMON_CLK
 	select SERIAL_CORE
 	help
 	  This enables the driver for the on-chip UARTs of the Amlogic

drivers/tty/serial/meson_uart.c

@@ -6,7 +6,6 @@
  */
 
 #include <linux/clk.h>
-#include <linux/clk-provider.h>
 #include <linux/console.h>
 #include <linux/delay.h>
 #include <linux/init.h>
@@ -66,7 +65,9 @@
 #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
@@ -75,11 +76,6 @@
 #define AML_UART_POLL_USEC		5
 #define AML_UART_TIMEOUT_USEC		10000
 
-struct meson_uart_data {
-	struct clk	*baud_clk;
-	bool		use_xtal_clk;
-};
-
 static struct uart_driver meson_uart_driver;
 
 static struct uart_port *meson_ports[AML_UART_PORT_NUM];
@@ -297,17 +293,19 @@ 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();
 
-	val = readl(port->membase + AML_UART_REG5);
+	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 |= 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,
@@ -365,13 +363,8 @@ static void meson_uart_set_termios(struct uart_port *port,
 	writel(val, port->membase + AML_UART_CONTROL);
 
 	baud = uart_get_baud_rate(port, termios, old, 50, 4000000);
-
-	spin_unlock_irqrestore(&port->lock, flags);
-
 	meson_uart_change_speed(port, baud);
 
-	spin_lock_irqsave(&port->lock, flags);
-
 	port->read_status_mask = AML_UART_TX_FIFO_WERR;
 	if (iflags & INPCK)
 		port->read_status_mask |= AML_UART_PARITY_ERR |
@@ -402,19 +395,23 @@ static int meson_uart_verify_port(struct uart_port *port,
 
 static void meson_uart_release_port(struct uart_port *port)
 {
-	struct meson_uart_data *private_data = port->private_data;
-
-	clk_disable_unprepare(private_data->baud_clk);
+	devm_iounmap(port->dev, port->membase);
+	port->membase = NULL;
+	devm_release_mem_region(port->dev, port->mapbase, port->mapsize);
 }
 
 static int meson_uart_request_port(struct uart_port *port)
 {
-	struct meson_uart_data *private_data = port->private_data;
-	int ret;
+	if (!devm_request_mem_region(port->dev, port->mapbase, port->mapsize,
+				     dev_name(port->dev))) {
+		dev_err(port->dev, "Memory region busy\n");
+		return -EBUSY;
+	}
 
-	ret = clk_prepare_enable(private_data->baud_clk);
-	if (ret)
-		return ret;
+	port->membase = devm_ioremap(port->dev, port->mapbase,
+					     port->mapsize);
+	if (!port->membase)
+		return -ENOMEM;
 
 	return 0;
 }
@@ -645,106 +642,57 @@ static struct uart_driver meson_uart_driver = {
 	.cons		= MESON_SERIAL_CONSOLE,
 };
 
-static const struct clk_div_table xtal_div_table[] = {
-	{ 0, 3 },
-	{ 1, 1 },
-	{ 2, 2 },
-	{ 3, 2 },
-};
+static inline struct clk *meson_uart_probe_clock(struct device *dev,
+						 const char *id)
+{
+	struct clk *clk = NULL;
+	int ret;
+
+	clk = devm_clk_get(dev, id);
+	if (IS_ERR(clk))
+		return clk;
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(dev, "couldn't enable clk\n");
+		return ERR_PTR(ret);
+	}
+
+	devm_add_action_or_reset(dev,
+			(void(*)(void *))clk_disable_unprepare,
+			clk);
 
-static u32 use_xtal_mux_table;
+	return clk;
+}
 
-static int meson_uart_probe_clocks(struct uart_port *port)
+static int meson_uart_probe_clocks(struct platform_device *pdev,
+				   struct uart_port *port)
 {
-	struct meson_uart_data *private_data = port->private_data;
-	struct clk *clk_baud, *clk_xtal;
-	struct clk_hw *hw, *clk81_div4_hw;
-	char clk_name[32];
-	struct clk_parent_data use_xtal_mux_parents;
+	struct clk *clk_xtal = NULL;
+	struct clk *clk_pclk = NULL;
+	struct clk *clk_baud = NULL;
 
-	clk_baud = devm_clk_get(port->dev, "baud");
-	if (IS_ERR(clk_baud)) {
-		dev_err(port->dev, "Failed to get the 'baud' clock\n");
-		return PTR_ERR(clk_baud);
-	}
+	clk_pclk = meson_uart_probe_clock(&pdev->dev, "pclk");
+	if (IS_ERR(clk_pclk))
+		return PTR_ERR(clk_pclk);
 
-	clk_xtal = devm_clk_get(port->dev, "xtal");
+	clk_xtal = meson_uart_probe_clock(&pdev->dev, "xtal");
 	if (IS_ERR(clk_xtal))
-		return dev_err_probe(port->dev, PTR_ERR(clk_xtal),
-				     "Failed to get the 'xtal' clock\n");
-
-	snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev),
-		 "clk81_div4");
-	clk81_div4_hw = devm_clk_hw_register_fixed_factor(port->dev,
-							  clk_name,
-							  __clk_get_name(clk_baud),
-							  CLK_SET_RATE_NO_REPARENT,
-							  1, 4);
-	if (IS_ERR(clk81_div4_hw))
-		return PTR_ERR(clk81_div4_hw);
-
-	snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev),
-		 "xtal_div");
-	hw = devm_clk_hw_register_divider_table(port->dev,
-						clk_name,
-						__clk_get_name(clk_baud),
-						CLK_SET_RATE_NO_REPARENT,
-						port->membase + AML_UART_REG5,
-						26, 2,
-						CLK_DIVIDER_ROUND_CLOSEST,
-						xtal_div_table, NULL);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-
-	if (private_data->use_xtal_clk) {
-		use_xtal_mux_table = 1;
-		use_xtal_mux_parents.hw = hw;
-	} else {
-		use_xtal_mux_parents.hw = clk81_div4_hw;
-	}
+		return PTR_ERR(clk_xtal);
+
+	clk_baud = meson_uart_probe_clock(&pdev->dev, "baud");
+	if (IS_ERR(clk_baud))
+		return PTR_ERR(clk_baud);
 
-	snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev),
-		 "use_xtal");
-	hw = __devm_clk_hw_register_mux(port->dev, NULL,
-					clk_name,
-					1,
-					NULL, NULL,
-					&use_xtal_mux_parents,
-					CLK_SET_RATE_PARENT,
-					port->membase + AML_UART_REG5,
-					24, 0x1,
-					CLK_MUX_ROUND_CLOSEST,
-					&use_xtal_mux_table, NULL);
-
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-
-	port->uartclk = clk_hw_get_rate(hw);
-
-	snprintf(clk_name, sizeof(clk_name), "%s#%s", dev_name(port->dev),
-		 "baud_div");
-	hw = devm_clk_hw_register_divider(port->dev,
-					  clk_name,
-					  clk_hw_get_name(hw),
-					  CLK_SET_RATE_PARENT,
-					  port->membase + AML_UART_REG5,
-					  0, 23,
-					  CLK_DIVIDER_ROUND_CLOSEST,
-					  NULL);
-	if (IS_ERR(hw))
-		return PTR_ERR(hw);
-
-	private_data->baud_clk = hw->clk;
+	port->uartclk = clk_get_rate(clk_baud);
 
 	return 0;
 }
 
 static int meson_uart_probe(struct platform_device *pdev)
 {
-	struct meson_uart_data *private_data;
 	struct resource *res_mem;
 	struct uart_port *port;
-	struct clk *pclk;
 	u32 fifosize = 64; /* Default is 64, 128 for EE UART_0 */
 	int ret = 0;
 	int irq;
@@ -770,15 +718,6 @@ static int meson_uart_probe(struct platform_device *pdev)
 	if (!res_mem)
 		return -ENODEV;
 
-	pclk = devm_clk_get(&pdev->dev, "pclk");
-	if (IS_ERR(pclk))
-		return dev_err_probe(&pdev->dev, PTR_ERR(pclk),
-				     "Failed to get the 'pclk' clock\n");
-
-	ret = clk_prepare_enable(pclk);
-	if (ret)
-		return ret;
-
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;
@@ -794,17 +733,9 @@ static int meson_uart_probe(struct platform_device *pdev)
 	if (!port)
 		return -ENOMEM;
 
-	port->membase = devm_ioremap_resource(&pdev->dev, res_mem);
-	if (IS_ERR(port->membase))
-		return PTR_ERR(port->membase);
-
-	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->use_xtal_clk = true;
+	ret = meson_uart_probe_clocks(pdev, port);
+	if (ret)
+		return ret;
 
 	port->iotype = UPIO_MEM;
 	port->mapbase = res_mem->start;
@@ -818,17 +749,15 @@ static int meson_uart_probe(struct platform_device *pdev)
 	port->x_char = 0;
 	port->ops = &meson_uart_ops;
 	port->fifosize = fifosize;
-	port->private_data = private_data;
-
-	ret = meson_uart_probe_clocks(port);
-	if (ret)
-		return ret;
 
 	meson_ports[pdev->id] = port;
 	platform_set_drvdata(pdev, port);
 
 	/* reset port before registering (and possibly registering console) */
-	meson_uart_reset(port);
+	if (meson_uart_request_port(port) >= 0) {
+		meson_uart_reset(port);
+		meson_uart_release_port(port);
+	}
 
 	ret = uart_add_one_port(&meson_uart_driver, port);
 	if (ret)
@@ -849,26 +778,10 @@ static int meson_uart_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id meson_uart_dt_match[] = {
-	{
-		.compatible = "amlogic,meson6-uart",
-		.data = (void *)false,
-	},
-	{
-		.compatible = "amlogic,meson8-uart",
-		.data = (void *)false,
-	},
-	{
-		.compatible = "amlogic,meson8b-uart",
-		.data = (void *)false,
-	},
-	{
-		.compatible = "amlogic,meson-gx-uart",
-		.data = (void *)true,
-	},
-	{
-		.compatible = "amlogic,meson-s4-uart",
-		.data = (void *)true,
-	},
+	{ .compatible = "amlogic,meson6-uart" },
+	{ .compatible = "amlogic,meson8-uart" },
+	{ .compatible = "amlogic,meson8b-uart" },
+	{ .compatible = "amlogic,meson-gx-uart" },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, meson_uart_dt_match);