linux-kernel - [PATCH 5/6] tty: serial: 8250: Add support for Moxa PCIe boards to switch interface

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240607114336.4496-6-crescentcy.hsieh@moxa.com>
Date: Fri,  7 Jun 2024 19:43:35 +0800
From: Crescent Hsieh <crescentcy.hsieh@...a.com>
To: Jiri Slaby <jirislaby@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org,
	Crescent Hsieh <crescentcy.hsieh@...a.com>
Subject: [PATCH 5/6] tty: serial: 8250: Add support for Moxa PCIe boards to switch interface

This patch adds support for Moxa PCIe serial boards to switch the serial
interface by using ioctl() command "TIOCSRS485" with the flags of struct
"serial_rs485":

    - RS232                  = (no flags are set)
    - RS422                  = SER_RS485_ENABLED | SER_RS485_MODE_RS422
    - RS485_2W (half-duplex) = SER_RS485_ENABLED
    - RS485_4W (full-duplex) = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX

Signed-off-by: Crescent Hsieh <crescentcy.hsieh@...a.com>
---
 drivers/tty/serial/8250/8250_pci.c | 46 ++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index e4e6493a5497..e2fcddec9ab5 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -2010,6 +2010,10 @@ enum {
 	MOXA_SUPP_RS485 = BIT(2),
 };
 
+static const struct serial_rs485 pci_moxa_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX | SER_RS485_MODE_RS422,
+};
+
 static bool pci_moxa_is_pcie(unsigned short device)
 {
 	if (device == PCI_DEVICE_ID_MOXA_CP102E     ||
@@ -2078,6 +2082,37 @@ static int pci_moxa_set_interface(const struct pci_dev *dev,
 	return 0;
 }
 
+/*
+ * Moxa PCIe boards support switching the serial interface using the ioctl()
+ * command "TIOCSRS485".
+ *
+ *      RS232                   = (no flags are set)
+ *      RS422                   = SER_RS485_ENABLED | SER_RS485_MODE_RS422
+ *      RS485_2W (half-duplex)  = SER_RS485_ENABLED
+ *      RS485_4W (full-duplex)  = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX
+ */
+static int pci_moxa_rs485_config(struct uart_port *port,
+				 struct ktermios *termios,
+				 struct serial_rs485 *rs485)
+{
+	struct pci_dev *dev = to_pci_dev(port->dev);
+	u8 mode = MOXA_RS232;
+
+	if (rs485->flags & SER_RS485_ENABLED) {
+		if (rs485->flags & SER_RS485_MODE_RS422)
+			mode = MOXA_RS422;
+		else if (rs485->flags & SER_RS485_RX_DURING_TX)
+			mode = MOXA_RS485_4W;
+		else
+			mode = MOXA_RS485_2W;
+	} else {
+		if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232))
+			return -ENODEV;
+	}
+
+	return pci_moxa_set_interface(dev, port->port_id, mode);
+}
+
 static int pci_moxa_init(struct pci_dev *dev)
 {
 	unsigned short device = dev->device;
@@ -2120,9 +2155,20 @@ pci_moxa_setup(struct serial_private *priv,
 		const struct pciserial_board *board,
 		struct uart_8250_port *port, int idx)
 {
+	struct pci_dev *dev = priv->dev;
 	unsigned int bar = FL_GET_BASE(board->flags);
 	int offset;
 
+	if (pci_moxa_is_pcie(dev->device) || pci_moxa_is_mini_pcie(dev->device)) {
+		if (pci_moxa_supported_rs(dev) & MOXA_SUPP_RS485) {
+			port->port.rs485_config = pci_moxa_rs485_config;
+			port->port.rs485_supported = pci_moxa_rs485_supported;
+
+			if (!(pci_moxa_supported_rs(dev) & MOXA_SUPP_RS232))
+				port->port.rs485.flags = SER_RS485_ENABLED | SER_RS485_MODE_RS422;
+		}
+	}
+
 	if (board->num_ports == 4 && idx == 3)
 		offset = 7 * board->uart_offset;
 	else
-- 
2.34.1