[PATCH v2 tty-next 1/3] 8250: microchip: pci1xxxx: Add driver for quad-uart support.

From: Kumaravel Thiagarajan
Date: Sat Oct 01 2022 - 02:18:19 EST

pci1xxxx is a PCIe switch with a multi-function endpoint on one of its
downstream ports. Quad-uart is one of the functions in the
multi-function endpoint. This driver loads for the quad-uart and
enumerates single or multiple instances of uart based on the PCIe
subsystem device ID.

Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@xxxxxxxxxxxxx>
---
Changes in v2:
- Use only the 62.5 MHz for baud clock.
- Define custom implementation for get_divisor and set_divisor.
- Use BOTHER instead of UPF_SPD_CUST for non standard baud rates (untested).
- Correct indentation in clock divisor computation.
- Remove unnecessary call to pci_save_state in probe function.
- Fix null pointer dereference in probe function.
- Move pci1xxxx_rs485_config to a separate patch.
- Depends on SERIAL_8250_PCI & default to SERIAL_8250.
- Change PORT_MCHP16550A to 100 from 124.
---
MAINTAINERS | 6 +
drivers/tty/serial/8250/8250_pci1xxxx.c | 394 ++++++++++++++++++++++++
drivers/tty/serial/8250/8250_port.c | 8 +
drivers/tty/serial/8250/Kconfig | 10 +
drivers/tty/serial/8250/Makefile | 1 +
include/uapi/linux/serial_core.h | 3 +
6 files changed, 422 insertions(+)
create mode 100644 drivers/tty/serial/8250/8250_pci1xxxx.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d30f26e07cd3..3390693d57ae 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -218,6 +218,12 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
F: drivers/tty/serial/8250*
F: include/linux/serial_8250.h

+MICROCHIP PCIe UART DRIVER
+M: Kumaravel Thiagarajan <kumaravel.thiagarajan@xxxxxxxxxxxxx>
+L: linux-serial@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/tty/serial/8250/8250_pci1xxxx.c
+
8390 NETWORK DRIVERS [WD80x3/SMC-ELITE, SMC-ULTRA, NE2000, 3C503, etc.]
L: netdev@xxxxxxxxxxxxxxx
S: Orphan / Obsolete
diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
new file mode 100644
index 000000000000..41a4b94f52b4
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
@@ -0,0 +1,394 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Probe module for 8250/16550-type MCHP PCI serial ports.
+ *
+ * Based on drivers/tty/serial/8250/8250_pci.c,
+ *
+ * Copyright (C) 2022 Microchip Technology Inc., All Rights Reserved.
+ */
+
+#include <linux/serial_core.h>
+#include <linux/8250_pci.h>
+#include <asm/byteorder.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/tty.h>
+#include <linux/io.h>
+#include "8250.h"
+
+#define PCI_VENDOR_ID_MCHP_PCI1XXXX 0x1055
+
+#define PCI_DEVICE_ID_MCHP_PCI12000 0xA002
+#define PCI_DEVICE_ID_MCHP_PCI11010 0xA012
+#define PCI_DEVICE_ID_MCHP_PCI11101 0xA022
+#define PCI_DEVICE_ID_MCHP_PCI11400 0xA032
+#define PCI_DEVICE_ID_MCHP_PCI11414 0xA042
+
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_4p 0x0001
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p012 0x0002
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p013 0x0003
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p023 0x0004
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p123 0x0005
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p01 0x0006
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p02 0x0007
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p03 0x0008
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p12 0x0009
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p13 0x000A
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p23 0x000B
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p0 0x000C
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p1 0x000D
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p2 0x000E
+#define PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p3 0x000F
+
+#define PCI_SUBDEVICE_ID_MCHP_PCI12000 0xA002
+#define PCI_SUBDEVICE_ID_MCHP_PCI11010 0xA012
+#define PCI_SUBDEVICE_ID_MCHP_PCI11101 0xA022
+#define PCI_SUBDEVICE_ID_MCHP_PCI11400 0xA032
+#define PCI_SUBDEVICE_ID_MCHP_PCI11414 0xA042
+
+#define UART_ACTV_REG 0x11
+#define UART_ACTV_SET_ACTIVE BIT(0)
+
+#define ADCL_CFG_REG 0x40
+#define ADCL_CFG_POL_SEL BIT(2)
+#define ADCL_CFG_PIN_SEL BIT(1)
+#define ADCL_CFG_EN BIT(0)
+
+#define CLK_SEL_REG 0x50
+#define CLK_SEL_MASK GENMASK(1, 0)
+#define CLK_SEL_166MHZ 0x01
+#define CLK_SEL_500MHZ 0x02
+
+#define CLK_DIVISOR_REG 0x54
+
+#define UART_PCI_CTRL_REG 0x80
+#define UART_PCI_CTRL_SET_MULTIPLE_MSI BIT(4)
+#define UART_PCI_CTRL_D3_CLK_ENABLE BIT(0)
+
+#define UART_WAKE_REG 0x8C
+#define UART_WAKE_MASK_REG 0x90
+#define UART_WAKE_N_PIN BIT(2)
+#define UART_WAKE_NCTS BIT(1)
+#define UART_WAKE_INT BIT(0)
+#define UART_WAKE_SRCS (UART_WAKE_N_PIN | UART_WAKE_NCTS | UART_WAKE_INT)
+
+#define UART_RESET_REG 0x94
+#define UART_RESET_D3_RESET_DISABLE BIT(16)
+
+#define UART_BIT_SAMPLE_CNT 16
+
+struct pci1xxxx_8250 {
+ struct pci_dev *dev;
+ unsigned int nr;
+ void __iomem *membase;
+ int line[];
+};
+
+static int pci1xxxx_setup_port(struct pci1xxxx_8250 *priv, struct uart_8250_port *port,
+ int offset)
+{
+ struct pci_dev *dev = priv->dev;
+
+ if (pci_resource_flags(dev, 0) & IORESOURCE_MEM) {
+ if (!pcim_iomap(dev, 0, 0) && !pcim_iomap_table(dev))
+ return -ENOMEM;
+
+ port->port.iotype = UPIO_MEM;
+ port->port.iobase = 0;
+ port->port.mapbase = pci_resource_start(dev, 0) + offset;
+ port->port.membase = pcim_iomap_table(dev)[0] + offset;
+ port->port.regshift = 0;
+ } else {
+ port->port.iotype = UPIO_PORT;
+ port->port.iobase = pci_resource_start(dev, 0) + offset;
+ port->port.mapbase = 0;
+ port->port.membase = NULL;
+ port->port.regshift = 0;
+ }
+
+ return 0;
+}
+
+static unsigned int pci1xxxx_get_divisor(struct uart_port *port,
+ unsigned int baud,
+ unsigned int *frac)
+{
+ unsigned int quot;
+
+ /*
+ * Calculate baud rate sampling period in nano seconds.
+ * Fractional part x denotes x/255 parts of a nano second.
+ */
+
+ quot = ((1000000000) / (baud * UART_BIT_SAMPLE_CNT));
+ *frac = (((1000000000 - (quot * baud * UART_BIT_SAMPLE_CNT)) /
+ UART_BIT_SAMPLE_CNT) * 255) / baud;
+
+ return quot;
+}
+
+static void pci1xxxx_set_divisor(struct uart_port *port, unsigned int baud,
+ unsigned int quot, unsigned int frac)
+{
+ writel((quot << 8) | frac, (port->membase + CLK_DIVISOR_REG));
+}
+
+static int pci1xxxx_get_num_ports(struct pci_dev *dev)
+{
+ int nr_ports = 1;
+
+ switch (dev->subsystem_device) {
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p0:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p1:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p2:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p3:
+ nr_ports = 1;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p01:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p02:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p03:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p12:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p13:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p23:
+ nr_ports = 2;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p012:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p123:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p013:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p023:
+ nr_ports = 3;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_4p:
+ case PCI_SUBDEVICE_ID_MCHP_PCI11414:
+ nr_ports = 4;
+ break;
+ }
+
+ return nr_ports;
+}
+
+static int pci1xxxx_setup(struct pci1xxxx_8250 *priv,
+ struct uart_8250_port *port, int idx)
+{
+ int first_offset = 0;
+ int offset;
+ int ret;
+
+ switch (priv->dev->subsystem_device) {
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p1:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p12:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p123:
+ first_offset = 256;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p2:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p23:
+ first_offset = 512;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p3:
+ first_offset = 768;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p02:
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p023:
+ if (idx > 0)
+ idx++;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p03:
+ if (idx > 0)
+ idx += 2;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p13:
+ first_offset = 256;
+ if (idx > 0)
+ idx++;
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p013:
+ if (idx > 1)
+ idx++;
+ break;
+ }
+
+ offset = first_offset + (idx * 256);
+ port->port.flags |= UPF_FIXED_TYPE | UPF_SKIP_TEST;
+ port->port.type = PORT_MCHP16550A;
+ port->port.set_termios = serial8250_do_set_termios;
+ port->port.get_divisor = pci1xxxx_get_divisor;
+ port->port.set_divisor = pci1xxxx_set_divisor;
+ ret = pci1xxxx_setup_port(priv, port, offset);
+ if (ret < 0)
+ return ret;
+
+ writeb(UART_ACTV_SET_ACTIVE, port->port.membase + UART_ACTV_REG);
+ writeb(UART_WAKE_SRCS, port->port.membase + UART_WAKE_REG);
+ writeb(UART_WAKE_N_PIN, port->port.membase + UART_WAKE_MASK_REG);
+
+ return 0;
+}
+
+static void pci1xxxx_irq_assign(struct pci1xxxx_8250 *priv,
+ struct uart_8250_port *uart, int idx)
+{
+ switch (priv->dev->subsystem_device) {
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p0:
+ case PCI_SUBDEVICE_ID_MCHP_PCI12000:
+ case PCI_SUBDEVICE_ID_MCHP_PCI11010:
+ case PCI_SUBDEVICE_ID_MCHP_PCI11101:
+ case PCI_SUBDEVICE_ID_MCHP_PCI11400:
+ uart->port.irq = pci_irq_vector(priv->dev, 0);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p1:
+ uart->port.irq = pci_irq_vector(priv->dev, 1);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p2:
+ uart->port.irq = pci_irq_vector(priv->dev, 2);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_1p3:
+ uart->port.irq = pci_irq_vector(priv->dev, 3);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p01:
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p02:
+ if (idx > 0)
+ idx++;
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p03:
+ if (idx > 0)
+ idx += 2;
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p12:
+ uart->port.irq = pci_irq_vector(priv->dev, idx + 1);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p13:
+ if (idx > 0)
+ idx += 1;
+ uart->port.irq = pci_irq_vector(priv->dev, idx + 1);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_2p23:
+ uart->port.irq = pci_irq_vector(priv->dev, idx + 2);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p012:
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p013:
+ if (idx > 1)
+ idx++;
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p023:
+ if (idx > 0)
+ idx++;
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_3p123:
+ uart->port.irq = pci_irq_vector(priv->dev, idx + 1);
+ break;
+ case PCI_SUBDEVICE_ID_MCHP_PCI1XXXX_4p:
+ case PCI_SUBDEVICE_ID_MCHP_PCI11414:
+ uart->port.irq = pci_irq_vector(priv->dev, idx);
+ break;
+ }
+}
+
+static int pci1xxxx_serial_probe(struct pci_dev *dev,
+ const struct pci_device_id *ent)
+{
+ struct pci1xxxx_8250 *priv;
+ struct uart_8250_port uart;
+ unsigned int nr_ports, i;
+ int num_vectors = 0;
+ int rc;
+
+ rc = pcim_enable_device(dev);
+ if (rc)
+ return rc;
+
+ nr_ports = pci1xxxx_get_num_ports(dev);
+
+ priv = devm_kzalloc(&dev->dev, struct_size(priv, line, nr_ports), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->membase = pcim_iomap(dev, 0, 0);
+ priv->dev = dev;
+ priv->nr = nr_ports;
+
+ pci_set_master(dev);
+
+ num_vectors = pci_alloc_irq_vectors(dev, 1, 4, PCI_IRQ_ALL_TYPES);
+ if (num_vectors < 0)
+ return num_vectors;
+
+ memset(&uart, 0, sizeof(uart));
+ uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_TYPE | UPF_FIXED_PORT;
+ uart.port.uartclk = 62500000;
+ uart.port.dev = &dev->dev;
+
+ if (num_vectors == 4)
+ writeb(UART_PCI_CTRL_SET_MULTIPLE_MSI, (priv->membase + UART_PCI_CTRL_REG));
+ else
+ uart.port.irq = pci_irq_vector(dev, 0);
+
+ for (i = 0; i < nr_ports; i++) {
+ if (num_vectors == 4)
+ pci1xxxx_irq_assign(priv, &uart, i);
+ priv->line[i] = -ENOSPC;
+ rc = pci1xxxx_setup(priv, &uart, i);
+ if (rc) {
+ dev_err(&dev->dev, "Failed to setup port %u\n", i);
+ break;
+ }
+ priv->line[i] = serial8250_register_8250_port(&uart);
+
+ if (priv->line[i] < 0) {
+ dev_err(&dev->dev,
+ "Couldn't register serial port %lx, irq %d, type %d, error %d\n",
+ uart.port.iobase, uart.port.irq,
+ uart.port.iotype, priv->line[i]);
+ break;
+ }
+ }
+
+ pci_set_drvdata(dev, priv);
+
+ return 0;
+}
+
+static void pci1xxxx_serial_remove(struct pci_dev *dev)
+{
+ struct pci1xxxx_8250 *priv = pci_get_drvdata(dev);
+ int i;
+
+ for (i = 0; i < priv->nr; i++) {
+ if (priv->line[i] >= 0)
+ serial8250_unregister_port(priv->line[i]);
+ }
+}
+
+static const struct pci_device_id pci1xxxx_pci_tbl[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_MCHP_PCI1XXXX, PCI_DEVICE_ID_MCHP_PCI11010) },
+ { PCI_DEVICE(PCI_VENDOR_ID_MCHP_PCI1XXXX, PCI_DEVICE_ID_MCHP_PCI11101) },
+ { PCI_DEVICE(PCI_VENDOR_ID_MCHP_PCI1XXXX, PCI_DEVICE_ID_MCHP_PCI11400) },
+ { PCI_DEVICE(PCI_VENDOR_ID_MCHP_PCI1XXXX, PCI_DEVICE_ID_MCHP_PCI11414) },
+ { PCI_DEVICE(PCI_VENDOR_ID_MCHP_PCI1XXXX, PCI_DEVICE_ID_MCHP_PCI12000) },
+ {}
+};
+MODULE_DEVICE_TABLE(pci, pci1xxxx_pci_tbl);
+
+static struct pci_driver pci1xxxx_pci_driver = {
+ .name = "pci1xxxx serial",
+ .probe = pci1xxxx_serial_probe,
+ .remove = pci1xxxx_serial_remove,
+ .id_table = pci1xxxx_pci_tbl,
+};
+
+module_pci_driver(pci1xxxx_pci_driver);
+
+MODULE_DESCRIPTION("Microchip Technology Inc. PCIe to UART module");
+MODULE_AUTHOR("Kumaravel Thiagarajan <kumaravel.thiagarajan@xxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 1d2a43214b48..ec2fe5fd7b02 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -313,6 +313,14 @@ static const struct serial8250_config uart_config[] = {
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO,
},
+ [PORT_MCHP16550A] = {
+ .name = "MCHP16550A",
+ .fifo_size = 256,
+ .tx_loadsz = 256,
+ .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01,
+ .rxtrig_bytes = {2, 66, 130, 194},
+ .flags = UART_CAP_FIFO,
+ },
};

/* Uart divisor latch read */
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index d0b49e15fbf5..a886727ff7bf 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -528,6 +528,16 @@ config SERIAL_8250_TEGRA
Select this option if you have machine with an NVIDIA Tegra SoC and
wish to enable 8250 serial driver for the Tegra serial interfaces.

+config SERIAL_8250_PCI1XXXX
+ tristate "Microchip 8250 based serial port"
+ depends on SERIAL_8250_PCI
+ default SERIAL_8250
+ help
+ Select this option if you have a setup with Microchip PCIe
+ Switch with serial port enabled and wish to enable 8250
+ serial driver for the serial interface. This driver support
+ will ensure to support baud rates upto 1.5Mpbs.
+
config SERIAL_8250_BCM7271
tristate "Broadcom 8250 based serial port"
depends on SERIAL_8250 && (ARCH_BRCMSTB || COMPILE_TEST)
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index bee908f99ea0..e900ff11e321 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_SERIAL_8250_LPSS) += 8250_lpss.o
obj-$(CONFIG_SERIAL_8250_MID) += 8250_mid.o
obj-$(CONFIG_SERIAL_8250_PERICOM) += 8250_pericom.o
obj-$(CONFIG_SERIAL_8250_PXA) += 8250_pxa.o
+obj-$(CONFIG_SERIAL_8250_PCI1XXXX) += 8250_pci1xxxx.o
obj-$(CONFIG_SERIAL_8250_TEGRA) += 8250_tegra.o
obj-$(CONFIG_SERIAL_8250_BCM7271) += 8250_bcm7271.o
obj-$(CONFIG_SERIAL_OF_PLATFORM) += 8250_of.o
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 3ba34d8378bd..281fa286555c 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -207,6 +207,9 @@
/* Atheros AR933X SoC */
#define PORT_AR933X 99

+/* MCHP 16550A UART with 256 byte FIFOs */
+#define PORT_MCHP16550A 100
+
/* ARC (Synopsys) on-chip UART */
#define PORT_ARC 101

--
2.25.1