linux-kernel - [PATCH v4 3/3] serial: 8250_pnp: Support configurable reg shift property

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Message-ID:
 <PSAPR06MB495296BC1D96B42A60F7C230C93D2@PSAPR06MB4952.apcprd06.prod.outlook.com>
Date: Wed,  3 Apr 2024 15:41:30 +0800
From: Guanbing Huang <albanhuang@...look.com>
To: gregkh@...uxfoundation.org,
	andriy.shevchenko@...el.com,
	rafael.j.wysocki@...el.com
Cc: linux-acpi@...r.kernel.org,
	tony@...mide.com,
	john.ogness@...utronix.de,
	yangyicong@...ilicon.com,
	jirislaby@...nel.org,
	linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org,
	lvjianmin@...ngson.cn,
	albanhuang@...cent.com,
	tombinfan@...cent.com
Subject: [PATCH v4 3/3] serial: 8250_pnp: Support configurable reg shift property

From: Guanbing Huang <albanhuang@...cent.com>

The 16550a serial port based on the ACPI table requires obtaining the
reg-shift attribute. In the ACPI scenario, If the reg-shift property
is not configured like in DTS, the 16550a serial driver cannot read or
write controller registers properly during initialization.

Signed-off-by: Guanbing Huang <albanhuang@...cent.com>
Reviewed-by: Bing Fan <tombinfan@...cent.com>
Tested-by: Linheng Du <dylanlhdu@...cent.com>
---
v3 -> v4: dependent on two pre patches: "pnp: Add dev_is_pnp() macro" and
          "serial: 8250_port: Add support of pnp irq to  __uart_read_properties()",
          the iotype is reserved, the mapsize is initialized, fix the UPF_SHARE_IRQ
	  flag, check for IRQ being absent
v2 -> v3: switch to use uart_read_port_properties(), change "Signed-off-by" to "Reviewed-by" and "Tested-by"
v1 -> v2: change the names after "Signed off by" to the real names

 drivers/tty/serial/8250/8250_pnp.c | 36 ++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_pnp.c b/drivers/tty/serial/8250/8250_pnp.c
index 1974bbadc975..292cb8e84b37 100644
--- a/drivers/tty/serial/8250/8250_pnp.c
+++ b/drivers/tty/serial/8250/8250_pnp.c
@@ -435,6 +435,7 @@ serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 {
 	struct uart_8250_port uart, *port;
 	int ret, line, flags = dev_id->driver_data;
+	unsigned char iotype;
 
 	if (flags & UNKNOWN_DEV) {
 		ret = serial_pnp_guess_board(dev);
@@ -443,25 +444,31 @@ serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 	}
 
 	memset(&uart, 0, sizeof(uart));
-	if (pnp_irq_valid(dev, 0))
-		uart.port.irq = pnp_irq(dev, 0);
 	if ((flags & CIR_PORT) && pnp_port_valid(dev, 2)) {
 		uart.port.iobase = pnp_port_start(dev, 2);
-		uart.port.iotype = UPIO_PORT;
+		iotype = UPIO_PORT;
 	} else if (pnp_port_valid(dev, 0)) {
 		uart.port.iobase = pnp_port_start(dev, 0);
-		uart.port.iotype = UPIO_PORT;
+		iotype = UPIO_PORT;
 	} else if (pnp_mem_valid(dev, 0)) {
 		uart.port.mapbase = pnp_mem_start(dev, 0);
-		uart.port.iotype = UPIO_MEM;
+		uart.port.mapsize = pnp_mem_end(dev, 0) - pnp_mem_start(dev, 0);
+		iotype = UPIO_MEM;
 		uart.port.flags = UPF_IOREMAP;
 	} else
 		return -ENODEV;
 
-	dev_dbg(&dev->dev,
-		 "Setup PNP port: port %#lx, mem %#llx, irq %u, type %u\n",
-		 uart.port.iobase, (unsigned long long)uart.port.mapbase,
-		 uart.port.irq, uart.port.iotype);
+	uart.port.uartclk = 1843200;
+	uart.port.dev = &dev->dev;
+
+	ret = uart_read_port_properties(&uart.port);
+	/* no interrupt -> fall back to polling */
+	if (ret == -ENXIO)
+		ret = 0;
+	if (ret)
+		return ret;
+
+	uart.port.iotype = iotype;
 
 	if (flags & CIR_PORT) {
 		uart.port.flags |= UPF_FIXED_PORT | UPF_FIXED_TYPE;
@@ -471,9 +478,14 @@ serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 	uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
 	if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
 		uart.port.flags |= UPF_SHARE_IRQ;
-	uart.port.uartclk = 1843200;
-	device_property_read_u32(&dev->dev, "clock-frequency", &uart.port.uartclk);
-	uart.port.dev = &dev->dev;
+	else
+		uart.port.flags &= ~UPF_SHARE_IRQ;
+
+
+	dev_dbg(&dev->dev,
+		 "Setup PNP port: port %#lx, mem %#llx, size %#llx, irq %u, type %u\n",
+		 uart.port.iobase, (unsigned long long)uart.port.mapbase,
+		 (unsigned long long)uart.port.mapsize, uart.port.irq, uart.port.iotype);
 
 	line = serial8250_register_8250_port(&uart);
 	if (line < 0 || (flags & CIR_PORT))
-- 
2.17.1