--- /dev/null
+// 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/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/units.h>
+#include <linux/tty.h>
+
+#include <asm/byteorder.h>
+
+#include "8250.h"
+#include "8250_pcilib.h"
+
+#define PCI_DEVICE_ID_EFAR_PCI12000            0xa002
+#define PCI_DEVICE_ID_EFAR_PCI11010            0xa012
+#define PCI_DEVICE_ID_EFAR_PCI11101            0xa022
+#define PCI_DEVICE_ID_EFAR_PCI11400            0xa032
+#define PCI_DEVICE_ID_EFAR_PCI11414            0xa042
+
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_4p      0x0001
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p012   0x0002
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p013   0x0003
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p023   0x0004
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p123   0x0005
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p01    0x0006
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p02    0x0007
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p03    0x0008
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p12    0x0009
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p13    0x000a
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p23    0x000b
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p0     0x000c
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p1     0x000d
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p2     0x000e
+#define PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p3     0x000f
+
+#define PCI_SUBDEVICE_ID_EFAR_PCI12000         PCI_DEVICE_ID_EFAR_PCI12000
+#define PCI_SUBDEVICE_ID_EFAR_PCI11010         PCI_DEVICE_ID_EFAR_PCI11010
+#define PCI_SUBDEVICE_ID_EFAR_PCI11101         PCI_DEVICE_ID_EFAR_PCI11101
+#define PCI_SUBDEVICE_ID_EFAR_PCI11400         PCI_DEVICE_ID_EFAR_PCI11400
+#define PCI_SUBDEVICE_ID_EFAR_PCI11414         PCI_DEVICE_ID_EFAR_PCI11414
+
+#define UART_ACTV_REG                          0x11
+#define UART_BLOCK_SET_ACTIVE                  BIT(0)
+
+#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 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 UART_BIT_SAMPLE_CNT                    16
+#define BAUD_CLOCK_DIV_INT_MSK                 GENMASK(31, 8)
+#define ADCL_CFG_RTS_DELAY_MASK                        GENMASK(11, 8)
+#define UART_CLOCK_DEFAULT                     (62500 * HZ_PER_KHZ)
+
+#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_BAUD_CLK_DIVISOR_REG              0x54
+
+#define UART_RESET_REG                         0x94
+#define UART_RESET_D3_RESET_DISABLE            BIT(16)
+
+#define MAX_PORTS                              4
+#define PORT_OFFSET                            0x100
+
+static const int logical_to_physical_port_idx[][MAX_PORTS] = {
+       {0,  1,  2,  3}, /* PCI12000, PCI11010, PCI11101, PCI11400, PCI11414 */
+       {0,  1,  2,  3}, /* PCI4p */
+       {0,  1,  2, -1}, /* PCI3p012 */
+       {0,  1,  3, -1}, /* PCI3p013 */
+       {0,  2,  3, -1}, /* PCI3p023 */
+       {1,  2,  3, -1}, /* PCI3p123 */
+       {0,  1, -1, -1}, /* PCI2p01 */
+       {0,  2, -1, -1}, /* PCI2p02 */
+       {0,  3, -1, -1}, /* PCI2p03 */
+       {1,  2, -1, -1}, /* PCI2p12 */
+       {1,  3, -1, -1}, /* PCI2p13 */
+       {2,  3, -1, -1}, /* PCI2p23 */
+       {0, -1, -1, -1}, /* PCI1p0 */
+       {1, -1, -1, -1}, /* PCI1p1 */
+       {2, -1, -1, -1}, /* PCI1p2 */
+       {3, -1, -1, -1}, /* PCI1p3 */
+};
+
+struct pci1xxxx_8250 {
+       unsigned int nr;
+       void __iomem *membase;
+       int line[];
+};
+
+static int pci1xxxx_get_num_ports(struct pci_dev *dev)
+{
+       switch (dev->subsystem_device) {
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p0:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p1:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p2:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p3:
+       case PCI_SUBDEVICE_ID_EFAR_PCI12000:
+       case PCI_SUBDEVICE_ID_EFAR_PCI11010:
+       case PCI_SUBDEVICE_ID_EFAR_PCI11101:
+       case PCI_SUBDEVICE_ID_EFAR_PCI11400:
+       default:
+               return 1;
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p01:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p02:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p03:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p12:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p13:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_2p23:
+               return 2;
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p012:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p123:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p013:
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_3p023:
+               return 3;
+       case PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_4p:
+       case PCI_SUBDEVICE_ID_EFAR_PCI11414:
+               return 4;
+       }
+}
+
+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 nanoseconds.
+        * Fractional part x denotes x/255 parts of a nanosecond.
+        */
+       quot = NSEC_PER_SEC / (baud * UART_BIT_SAMPLE_CNT);
+       *frac = (NSEC_PER_SEC - quot * baud * UART_BIT_SAMPLE_CNT) *
+                 255 / UART_BIT_SAMPLE_CNT / baud;
+
+       return quot;
+}
+
+static void pci1xxxx_set_divisor(struct uart_port *port, unsigned int baud,
+                                unsigned int quot, unsigned int frac)
+{
+       writel(FIELD_PREP(BAUD_CLOCK_DIV_INT_MSK, quot) | frac,
+              port->membase + UART_BAUD_CLK_DIVISOR_REG);
+}
+
+static int pci1xxxx_setup(struct pci_dev *pdev,
+                         struct uart_8250_port *port, int port_idx)
+{
+       int ret;
+
+       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 = serial8250_pci_setup_port(pdev, port, 0, PORT_OFFSET * port_idx, 0);
+       if (ret < 0)
+               return ret;
+
+       writeb(UART_BLOCK_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 unsigned int pci1xxxx_get_max_port(int subsys_dev)
+{
+       unsigned int i = MAX_PORTS;
+
+       if (subsys_dev < ARRAY_SIZE(logical_to_physical_port_idx))
+               while (i--) {
+                       if (logical_to_physical_port_idx[subsys_dev][i] != -1)
+                               return logical_to_physical_port_idx[subsys_dev][i] + 1;
+               }
+
+       if (subsys_dev == PCI_SUBDEVICE_ID_EFAR_PCI11414)
+               return 4;
+
+       return 1;
+}
+
+static int pci1xxxx_logical_to_physical_port_translate(int subsys_dev, int port)
+{
+       if (subsys_dev < ARRAY_SIZE(logical_to_physical_port_idx))
+               return logical_to_physical_port_idx[subsys_dev][port];
+
+       return logical_to_physical_port_idx[0][port];
+}
+
+static int pci1xxxx_serial_probe(struct pci_dev *pdev,
+                                const struct pci_device_id *id)
+{
+       struct device *dev = &pdev->dev;
+       struct pci1xxxx_8250 *priv;
+       struct uart_8250_port uart;
+       unsigned int max_vec_reqd;
+       unsigned int nr_ports, i;
+       int num_vectors;
+       int subsys_dev;
+       int port_idx;
+       int rc;
+
+       rc = pcim_enable_device(pdev);
+       if (rc)
+               return rc;
+
+       nr_ports = pci1xxxx_get_num_ports(pdev);
+
+       priv = devm_kzalloc(dev, struct_size(priv, line, nr_ports), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       priv->membase = pci_ioremap_bar(pdev, 0);
+       if (!priv->membase)
+               return -ENOMEM;
+
+       pci_set_master(pdev);
+
+       priv->nr = nr_ports;
+
+       subsys_dev = pdev->subsystem_device;
+       max_vec_reqd = pci1xxxx_get_max_port(subsys_dev);
+
+       num_vectors = pci_alloc_irq_vectors(pdev, 1, max_vec_reqd, PCI_IRQ_ALL_TYPES);
+       if (num_vectors < 0) {
+               pci_iounmap(pdev, priv->membase);
+               return num_vectors;
+       }
+
+       memset(&uart, 0, sizeof(uart));
+       uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT;
+       uart.port.uartclk = UART_CLOCK_DEFAULT;
+       uart.port.dev = dev;
+
+       if (num_vectors == max_vec_reqd)
+               writeb(UART_PCI_CTRL_SET_MULTIPLE_MSI, priv->membase + UART_PCI_CTRL_REG);
+
+       for (i = 0; i < nr_ports; i++) {
+               priv->line[i] = -ENODEV;
+
+               port_idx = pci1xxxx_logical_to_physical_port_translate(subsys_dev, i);
+
+               if (num_vectors == max_vec_reqd)
+                       uart.port.irq = pci_irq_vector(pdev, port_idx);
+               else
+                       uart.port.irq = pci_irq_vector(pdev, 0);
+
+               rc = pci1xxxx_setup(pdev, &uart, port_idx);
+               if (rc) {
+                       dev_warn(dev, "Failed to setup port %u\n", i);
+                       continue;
+               }
+
+               priv->line[i] = serial8250_register_8250_port(&uart);
+               if (priv->line[i] < 0) {
+                       dev_warn(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]);
+               }
+       }
+
+       pci_set_drvdata(pdev, priv);
+
+       return 0;
+}
+
+static void pci1xxxx_serial_remove(struct pci_dev *dev)
+{
+       struct pci1xxxx_8250 *priv = pci_get_drvdata(dev);
+       unsigned int i;
+
+       for (i = 0; i < priv->nr; i++) {
+               if (priv->line[i] >= 0)
+                       serial8250_unregister_port(priv->line[i]);
+       }
+
+       pci_free_irq_vectors(dev);
+       pci_iounmap(dev, priv->membase);
+}
+
+static const struct pci_device_id pci1xxxx_pci_tbl[] = {
+       { PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_PCI11010) },
+       { PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_PCI11101) },
+       { PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_PCI11400) },
+       { PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_PCI11414) },
+       { PCI_VDEVICE(EFAR, PCI_DEVICE_ID_EFAR_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);
+
+static_assert((ARRAY_SIZE(logical_to_physical_port_idx) == PCI_SUBDEVICE_ID_EFAR_PCI1XXXX_1p3 + 1));
+
+MODULE_IMPORT_NS(SERIAL_8250_PCI);
+MODULE_DESCRIPTION("Microchip Technology Inc. PCIe to UART module");
+MODULE_AUTHOR("Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>");
+MODULE_AUTHOR("Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>");
+MODULE_LICENSE("GPL");