Re: Hardware flowcontrol on XR17D154

["Søren holm" <sgh@sgh.dk>]

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Hi

Here is my patch to add EFR-support for XR17D15x
Do you have any comments, since this is my first patch to the kernel ?

-- 
Søren Holm

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From fcf3746a15af26ddd2e8e2421f81799b15c27707 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B8ren=20Holm?= <sh@mikrofyn.com>
Date: Fri, 2 Sep 2011 12:18:59 +0200
Subject: [PATCH] serial: Support the EFR-register of XR1715x uarts.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The EFR (Enhenced-Features-Register) is located at a different offset
than the other devices supporting UART_CAP_EFR. This change add a special
setup quick to set UPF_EXAR_EFR on the port. UPF_EXAR_EFR is then used to
the port type to PORT_XR17D15X since it is for sure a XR17D15X uart.

Signed-off-by: Søren Holm <sgh@sgh.dk>
---
 drivers/tty/serial/8250.c     |   18 +++++++++++++++++-
 drivers/tty/serial/8250_pci.c |   33 +++++++++++++++++++++++++++++++++
 include/linux/serial_core.h   |    4 +++-
 include/linux/serial_reg.h    |    1 +
 4 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index 7f50999..d626ca8 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -309,6 +309,13 @@ static const struct serial8250_config uart_config[] = {
 				  UART_FCR_T_TRIG_01,
 		.flags		= UART_CAP_FIFO | UART_CAP_RTOIE,
 	},
+	[PORT_XR17D15X] = {
+		.name		= "XR17D15X",
+		.fifo_size	= 64,
+		.tx_loadsz	= 64,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+		.flags		= UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR,
+	},
 };
 
 #if defined(CONFIG_MIPS_ALCHEMY)
@@ -1119,6 +1126,12 @@ static void autoconfig_16550a(struct uart_8250_port *up)
 	}
 	serial_outp(up, UART_IER, iersave);
 
+	// Exar uarts have EFR in a weird location
+	if (up->port.flags & UPF_EXAR_EFR) {
+		up->port.type = PORT_XR17D15X;
+		up->capabilities |= UART_CAP_AFE | UART_CAP_EFR;
+	}
+
 	/*
 	 * We distinguish between 16550A and U6 16550A by counting
 	 * how many bytes are in the FIFO.
@@ -2458,7 +2471,10 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
 			efr |= UART_EFR_CTS;
 
 		serial_outp(up, UART_LCR, UART_LCR_CONF_MODE_B);
-		serial_outp(up, UART_EFR, efr);
+		if (up->port.flags & UPF_EXAR_EFR)
+			serial_outp(up, UART_XR_EFR, efr);
+		else
+			serial_outp(up, UART_EFR, efr);
 	}
 
 #ifdef CONFIG_ARCH_OMAP
diff --git a/drivers/tty/serial/8250_pci.c b/drivers/tty/serial/8250_pci.c
index 3abeca2..52247da 100644
--- a/drivers/tty/serial/8250_pci.c
+++ b/drivers/tty/serial/8250_pci.c
@@ -1101,6 +1101,15 @@ static int pci_eg20t_init(struct pci_dev *dev)
 #endif
 }
 
+static int
+pci_xr17c154_setup(struct serial_private *priv,
+		  const struct pciserial_board *board,
+		  struct uart_port *port, int idx)
+{
+	port->flags |= UPF_EXAR_EFR;
+	return pci_default_setup(priv, board, port, idx);
+}
+
 /* This should be in linux/pci_ids.h */
 #define PCI_VENDOR_ID_SBSMODULARIO	0x124B
 #define PCI_SUBVENDOR_ID_SBSMODULARIO	0x124B
@@ -1506,6 +1515,30 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = {
 		.setup		= pci_timedia_setup,
 	},
 	/*
+	 * Exar cards
+	 */
+	{
+		.vendor = PCI_VENDOR_ID_EXAR,
+		.device = PCI_DEVICE_ID_EXAR_XR17C152,
+		.subvendor	= PCI_ANY_ID,
+		.subdevice	= PCI_ANY_ID,
+		.setup		= pci_xr17c154_setup,
+	},
+	{
+		.vendor = PCI_VENDOR_ID_EXAR,
+		.device = PCI_DEVICE_ID_EXAR_XR17C154,
+		.subvendor	= PCI_ANY_ID,
+		.subdevice	= PCI_ANY_ID,
+		.setup		= pci_xr17c154_setup,
+	},
+	{
+		.vendor = PCI_VENDOR_ID_EXAR,
+		.device = PCI_DEVICE_ID_EXAR_XR17C158,
+		.subvendor	= PCI_ANY_ID,
+		.subdevice	= PCI_ANY_ID,
+		.setup		= pci_xr17c154_setup,
+	},
+	/*
 	 * Xircom cards
 	 */
 	{
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index a5c3114..01aa96b 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -46,7 +46,8 @@
 #define PORT_AR7	18	/* Texas Instruments AR7 internal UART */
 #define PORT_U6_16550A	19	/* ST-Ericsson U6xxx internal UART */
 #define PORT_TEGRA	20	/* NVIDIA Tegra internal UART */
-#define PORT_MAX_8250	20	/* max port ID */
+#define PORT_XR17D15X	21	/* Exar XR17D15x UART */
+#define PORT_MAX_8250	21	/* max port ID */
 
 /*
  * ARM specific type numbers.  These are not currently guaranteed
@@ -350,6 +351,7 @@ struct uart_port {
 #define UPF_MAGIC_MULTIPLIER	((__force upf_t) (1 << 16))
 #define UPF_CONS_FLOW		((__force upf_t) (1 << 23))
 #define UPF_SHARE_IRQ		((__force upf_t) (1 << 24))
+#define UPF_EXAR_EFR		((__force upf_t) (1 << 25))
 /* The exact UART type is known and should not be probed.  */
 #define UPF_FIXED_TYPE		((__force upf_t) (1 << 27))
 #define UPF_BOOT_AUTOCONF	((__force upf_t) (1 << 28))
diff --git a/include/linux/serial_reg.h b/include/linux/serial_reg.h
index c75bda3..63a749a 100644
--- a/include/linux/serial_reg.h
+++ b/include/linux/serial_reg.h
@@ -152,6 +152,7 @@
  * LCR=0xBF (or DLAB=1 for 16C660)
  */
 #define UART_EFR	2	/* I/O: Extended Features Register */
+#define UART_XR_EFR	9	/* I/O: Extended Features Register for Exar XR17D154 */
 #define UART_EFR_CTS		0x80 /* CTS flow control */
 #define UART_EFR_RTS		0x40 /* RTS flow control */
 #define UART_EFR_SCD		0x20 /* Special character detect */
-- 
1.7.4.1