[PATCH v10 tty-next 0/4] serial: 8250_pci1xxxx: Add driver for the pci1xxxx's quad-uart function

[PATCH v10 tty-next 0/4] serial: 8250_pci1xxxx: Add driver for the pci1xxxx's quad-uart function

[Kumaravel Thiagarajan]

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 patch adds device driver for the quad-uart function and
enumerates between 1 to 4 instances of uarts based on the PCIe subsystem
device ID.

The changes from v1->v2->v3->v4->v5->v6->v7->v8->v9->v10 are mentioned in
each patch in the patchset.

Thanks to Andy Shevchenko, Ilpo Jarvinen, Chritophe JAILLET, Geert
Uytterhoeven, Greg KH, Jiri Slaby for their review comments.

Kumaravel Thiagarajan (4):
  serial: 8250_pci: Add serial8250_pci_setup_port definition in
    8250_pcilib.c
  serial: 8250_pci1xxxx: Add driver for quad-uart support
  serial: 8250_pci1xxxx: Add RS485 support to quad-uart driver
  serial: 8250_pci1xxxx: Add power management functions to quad-uart
    driver

 MAINTAINERS                             |   7 +
 drivers/tty/serial/8250/8250_pci.c      |  25 +-
 drivers/tty/serial/8250/8250_pci1xxxx.c | 494 ++++++++++++++++++++++++
 drivers/tty/serial/8250/8250_pcilib.c   |  39 ++
 drivers/tty/serial/8250/8250_pcilib.h   |  15 +
 drivers/tty/serial/8250/8250_port.c     |   8 +
 drivers/tty/serial/8250/Kconfig         |  15 +
 drivers/tty/serial/8250/Makefile        |   2 +
 include/uapi/linux/serial_core.h        |   3 +
 9 files changed, 586 insertions(+), 22 deletions(-)
 create mode 100644 drivers/tty/serial/8250/8250_pci1xxxx.c
 create mode 100644 drivers/tty/serial/8250/8250_pcilib.c
 create mode 100644 drivers/tty/serial/8250/8250_pcilib.h

-- 
2.25.1

[PATCH v10 tty-next 1/4] serial: 8250_pci: Add serial8250_pci_setup_port definition in 8250_pcilib.c

[Kumaravel Thiagarajan]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="y", Size: 5975 bytes --]

Move implementation of setup_port func() to serial8250_pci_setup_port.

Co-developed-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Changes in v10:
- No Change

Changes in v9:
- Added License in 8250_pcilib.c file

Changes in v8:
- Moved SERIAL_8250_PCILIB above 8250_PCI

Changes in v7:
- Used namespace 'SERIAL_8250_PCI' while exporting and importing symbols
- Included structures used in function declaration in 8250_pcilib.h file

Changes in v6:
- Made this patch first patch of the patch series

Changes in v5:
- This is the new patch added in v5 version of this patchset
- Moved implementation of setup_port from 8250_pci.c to 8250_pcilib.c
---
 drivers/tty/serial/8250/8250_pci.c    | 25 +++--------------
 drivers/tty/serial/8250/8250_pcilib.c | 39 +++++++++++++++++++++++++++
 drivers/tty/serial/8250/8250_pcilib.h | 15 +++++++++++
 drivers/tty/serial/8250/Kconfig       |  4 +++
 drivers/tty/serial/8250/Makefile      |  1 +
 5 files changed, 62 insertions(+), 22 deletions(-)
 create mode 100644 drivers/tty/serial/8250/8250_pcilib.c
 create mode 100644 drivers/tty/serial/8250/8250_pcilib.h

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 6f66dc2ebacc..58cc9e19bd20 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -24,6 +24,7 @@
 #include <asm/io.h>
 
 #include "8250.h"
+#include "8250_pcilib.h"
 
 /*
  * init function returns:
@@ -89,28 +90,7 @@ static int
 setup_port(struct serial_private *priv, struct uart_8250_port *port,
 	   u8 bar, unsigned int offset, int regshift)
 {
-	struct pci_dev *dev = priv->dev;
-
-	if (bar >= PCI_STD_NUM_BARS)
-		return -EINVAL;
-
-	if (pci_resource_flags(dev, bar) & IORESOURCE_MEM) {
-		if (!pcim_iomap(dev, bar, 0) && !pcim_iomap_table(dev))
-			return -ENOMEM;
-
-		port->port.iotype = UPIO_MEM;
-		port->port.iobase = 0;
-		port->port.mapbase = pci_resource_start(dev, bar) + offset;
-		port->port.membase = pcim_iomap_table(dev)[bar] + offset;
-		port->port.regshift = regshift;
-	} else {
-		port->port.iotype = UPIO_PORT;
-		port->port.iobase = pci_resource_start(dev, bar) + offset;
-		port->port.mapbase = 0;
-		port->port.membase = NULL;
-		port->port.regshift = 0;
-	}
-	return 0;
+	return serial8250_pci_setup_port(priv->dev, port, bar, offset, regshift);
 }
 
 /*
@@ -5759,3 +5739,4 @@ module_pci_driver(serial_pci_driver);
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Generic 8250/16x50 PCI serial probe module");
 MODULE_DEVICE_TABLE(pci, serial_pci_tbl);
+MODULE_IMPORT_NS(SERIAL_8250_PCI);
diff --git a/drivers/tty/serial/8250/8250_pcilib.c b/drivers/tty/serial/8250/8250_pcilib.c
new file mode 100644
index 000000000000..a7124cda1871
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_pcilib.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 8250 PCI library.
+ *
+ * Copyright (C) 2001 Russell King, All Rights Reserved.
+ */
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+
+#include "8250.h"
+
+int serial8250_pci_setup_port(struct pci_dev *dev, struct uart_8250_port *port,
+		   u8 bar, unsigned int offset, int regshift)
+{
+	if (bar >= PCI_STD_NUM_BARS)
+		return -EINVAL;
+
+	if (pci_resource_flags(dev, bar) & IORESOURCE_MEM) {
+		if (!pcim_iomap(dev, bar, 0) && !pcim_iomap_table(dev))
+			return -ENOMEM;
+
+		port->port.iotype = UPIO_MEM;
+		port->port.iobase = 0;
+		port->port.mapbase = pci_resource_start(dev, bar) + offset;
+		port->port.membase = pcim_iomap_table(dev)[bar] + offset;
+		port->port.regshift = regshift;
+	} else {
+		port->port.iotype = UPIO_PORT;
+		port->port.iobase = pci_resource_start(dev, bar) + offset;
+		port->port.mapbase = 0;
+		port->port.membase = NULL;
+		port->port.regshift = 0;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(serial8250_pci_setup_port, SERIAL_8250_PCI);
+MODULE_LICENSE("GPL");
diff --git a/drivers/tty/serial/8250/8250_pcilib.h b/drivers/tty/serial/8250/8250_pcilib.h
new file mode 100644
index 000000000000..1aaf1b50ce9c
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_pcilib.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * 8250 PCI library header file.
+ *
+ * Copyright (C) 2001 Russell King, All Rights Reserved.
+ */
+
+#include <linux/types.h>
+
+struct pci_dev;
+
+struct uart_8250_port;
+
+int serial8250_pci_setup_port(struct pci_dev *dev, struct uart_8250_port *port, u8 bar,
+		   unsigned int offset, int regshift);
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index d0b49e15fbf5..768b73d5cb9a 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -129,9 +129,13 @@ config SERIAL_8250_DMA
 	  This builds DMA support that can be used with 8250/16650
 	  compatible UART controllers that support DMA signaling.
 
+config SERIAL_8250_PCILIB
+	bool
+
 config SERIAL_8250_PCI
 	tristate "8250/16550 PCI device support"
 	depends on SERIAL_8250 && PCI
+	select SERIAL_8250_PCILIB
 	default SERIAL_8250
 	help
 	  This builds standard PCI serial support. You may be able to
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index bee908f99ea0..b9179d1f104b 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SERIAL_8250)		+= 8250.o 8250_base.o
 8250_base-$(CONFIG_SERIAL_8250_DMA)	+= 8250_dma.o
 8250_base-$(CONFIG_SERIAL_8250_DWLIB)	+= 8250_dwlib.o
 8250_base-$(CONFIG_SERIAL_8250_FINTEK)	+= 8250_fintek.o
+8250_base-$(CONFIG_SERIAL_8250_PCILIB)	+= 8250_pcilib.o
 obj-$(CONFIG_SERIAL_8250_GSC)		+= 8250_gsc.o
 obj-$(CONFIG_SERIAL_8250_PCI)		+= 8250_pci.o
 obj-$(CONFIG_SERIAL_8250_EXAR)		+= 8250_exar.o
-- 
2.25.1

[PATCH v10 tty-next 2/4] serial: 8250_pci1xxxx: Add driver for quad-uart support

[Kumaravel Thiagarajan]

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.

Co-developed-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
---
Changes in v10:
- Added spaces to improve readability
- Used macro for PORT_OFFSET
- Used pci_free_irq_vectors API

Changes in v9:
- Reshuffled code logically
- Modified datatype of few variables
- Removed un-necessary else
- Used PCI_VDEVICE()

Changes in v8:
- Requested only required number of interrupt vectors in
  pci_alloc_irq_vectors
  API based on sub-device id

Changes in v7:
- Used appropriate error codes
- Moved logical_to_physical_port_idx array to a function

Changes in v6:
- Removed un-necessary paranthesis
- Used array and removed switch cases to reduce complexity
- Handled failure case of pcim_iomap

Changes in v5:
- Used tabs instead of spaces in MACRO definitions for readability
- Removed assignments that are not required
- Removed redundant blank lines

Changes in v4:
- Renamed pci_setup_port to serial8250_pci_setup_port
- Added Copyright information to 8250_pcilib.c

Changes in v3:
- Used NSEC_PER_SEC, HZ_PER_MHZ, FIELD_PREP, FIELD_GET MACROs wherever
  necessary
- Handled failure case of serial8250_register_8250_port properly
- Moved pci_setup_port to 8250_pcilib.c

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                             |   7 +
 drivers/tty/serial/8250/8250_pci1xxxx.c | 329 ++++++++++++++++++++++++
 drivers/tty/serial/8250/8250_port.c     |   8 +
 drivers/tty/serial/8250/Kconfig         |  11 +
 drivers/tty/serial/8250/Makefile        |   1 +
 include/uapi/linux/serial_core.h        |   3 +
 6 files changed, 359 insertions(+)
 create mode 100644 drivers/tty/serial/8250/8250_pci1xxxx.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d30f26e07cd3..aa98deaba249 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13434,6 +13434,13 @@ F:	Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
 F:	drivers/nvmem/microchip-otpc.c
 F:	include/dt-bindings/nvmem/microchip,sama7g5-otpc.h
 
+MICROCHIP PCIe UART DRIVER
+M:	Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
+M:	Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
+L:	linux-serial@vger.kernel.org
+S:	Maintained
+F:	drivers/tty/serial/8250/8250_pci1xxxx.c
+
 MICROCHIP PWM DRIVER
 M:	Claudiu Beznea <claudiu.beznea@microchip.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
new file mode 100644
index 000000000000..ea04c014edb9
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
@@ -0,0 +1,329 @@
+// 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");
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 768b73d5cb9a..588a73c0f4e8 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -295,6 +295,17 @@ config SERIAL_8250_HUB6
 	  To compile this driver as a module, choose M here: the module
 	  will be called 8250_hub6.
 
+config SERIAL_8250_PCI1XXXX
+	tristate "Microchip 8250 based serial port"
+	depends on SERIAL_8250 && PCI
+	select SERIAL_8250_PCILIB
+	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.
+
 #
 # Misc. options/drivers.
 #
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index b9179d1f104b..98202fdf39f8 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_SERIAL_8250_ACCENT)	+= 8250_accent.o
 obj-$(CONFIG_SERIAL_8250_BOCA)		+= 8250_boca.o
 obj-$(CONFIG_SERIAL_8250_EXAR_ST16C554)	+= 8250_exar_st16c554.o
 obj-$(CONFIG_SERIAL_8250_HUB6)		+= 8250_hub6.o
+obj-$(CONFIG_SERIAL_8250_PCI1XXXX)	+= 8250_pci1xxxx.o
 obj-$(CONFIG_SERIAL_8250_FSL)		+= 8250_fsl.o
 obj-$(CONFIG_SERIAL_8250_MEN_MCB)	+= 8250_men_mcb.o
 obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.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

Re: [PATCH v10 tty-next 2/4] serial: 8250_pci1xxxx: Add driver for quad-uart support

[Andy Shevchenko]

On Sun, Dec 18, 2022 at 12:45:05AM +0530, Kumaravel Thiagarajan wrote:
> 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.

This version LGTM,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
thank you.

> Co-developed-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
> Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
> Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
> ---
> Changes in v10:
> - Added spaces to improve readability
> - Used macro for PORT_OFFSET
> - Used pci_free_irq_vectors API
> 
> Changes in v9:
> - Reshuffled code logically
> - Modified datatype of few variables
> - Removed un-necessary else
> - Used PCI_VDEVICE()
> 
> Changes in v8:
> - Requested only required number of interrupt vectors in
>   pci_alloc_irq_vectors
>   API based on sub-device id
> 
> Changes in v7:
> - Used appropriate error codes
> - Moved logical_to_physical_port_idx array to a function
> 
> Changes in v6:
> - Removed un-necessary paranthesis
> - Used array and removed switch cases to reduce complexity
> - Handled failure case of pcim_iomap
> 
> Changes in v5:
> - Used tabs instead of spaces in MACRO definitions for readability
> - Removed assignments that are not required
> - Removed redundant blank lines
> 
> Changes in v4:
> - Renamed pci_setup_port to serial8250_pci_setup_port
> - Added Copyright information to 8250_pcilib.c
> 
> Changes in v3:
> - Used NSEC_PER_SEC, HZ_PER_MHZ, FIELD_PREP, FIELD_GET MACROs wherever
>   necessary
> - Handled failure case of serial8250_register_8250_port properly
> - Moved pci_setup_port to 8250_pcilib.c
> 
> 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                             |   7 +
>  drivers/tty/serial/8250/8250_pci1xxxx.c | 329 ++++++++++++++++++++++++
>  drivers/tty/serial/8250/8250_port.c     |   8 +
>  drivers/tty/serial/8250/Kconfig         |  11 +
>  drivers/tty/serial/8250/Makefile        |   1 +
>  include/uapi/linux/serial_core.h        |   3 +
>  6 files changed, 359 insertions(+)
>  create mode 100644 drivers/tty/serial/8250/8250_pci1xxxx.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d30f26e07cd3..aa98deaba249 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13434,6 +13434,13 @@ F:	Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
>  F:	drivers/nvmem/microchip-otpc.c
>  F:	include/dt-bindings/nvmem/microchip,sama7g5-otpc.h
>  
> +MICROCHIP PCIe UART DRIVER
> +M:	Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
> +M:	Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
> +L:	linux-serial@vger.kernel.org
> +S:	Maintained
> +F:	drivers/tty/serial/8250/8250_pci1xxxx.c
> +
>  MICROCHIP PWM DRIVER
>  M:	Claudiu Beznea <claudiu.beznea@microchip.com>
>  L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
> diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
> new file mode 100644
> index 000000000000..ea04c014edb9
> --- /dev/null
> +++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
> @@ -0,0 +1,329 @@
> +// 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");
> 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 768b73d5cb9a..588a73c0f4e8 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -295,6 +295,17 @@ config SERIAL_8250_HUB6
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called 8250_hub6.
>  
> +config SERIAL_8250_PCI1XXXX
> +	tristate "Microchip 8250 based serial port"
> +	depends on SERIAL_8250 && PCI
> +	select SERIAL_8250_PCILIB
> +	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.
> +
>  #
>  # Misc. options/drivers.
>  #
> diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
> index b9179d1f104b..98202fdf39f8 100644
> --- a/drivers/tty/serial/8250/Makefile
> +++ b/drivers/tty/serial/8250/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_SERIAL_8250_ACCENT)	+= 8250_accent.o
>  obj-$(CONFIG_SERIAL_8250_BOCA)		+= 8250_boca.o
>  obj-$(CONFIG_SERIAL_8250_EXAR_ST16C554)	+= 8250_exar_st16c554.o
>  obj-$(CONFIG_SERIAL_8250_HUB6)		+= 8250_hub6.o
> +obj-$(CONFIG_SERIAL_8250_PCI1XXXX)	+= 8250_pci1xxxx.o
>  obj-$(CONFIG_SERIAL_8250_FSL)		+= 8250_fsl.o
>  obj-$(CONFIG_SERIAL_8250_MEN_MCB)	+= 8250_men_mcb.o
>  obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.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
> 

-- 
With Best Regards,
Andy Shevchenko

[PATCH v10 tty-next 3/4] serial: 8250_pci1xxxx: Add RS485 support to quad-uart driver

[Kumaravel Thiagarajan]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="y", Size: 3481 bytes --]

pci1xxxx uart supports RS485 mode of operation in the hardware with
auto-direction control with configurable delay for releasing RTS after
the transmission. This patch adds support for the RS485 mode.

Co-developed-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
Changes in v10:
- No Change

Changes in v9:
- No Change

Changes in v8:
- Modified datatype of delay_in_baud_periods to u32

Changes in v7:
- No Change

Changes in v6:
- Modified datatype of delay_in_baud_periods to u64 to avoid overflows

Changes in v5:
- Removed unnecessary assignments
- Corrected styling issues in comments

Changes in v4:
- No Change

Changes in v3:
- Remove flags sanitization in driver which is taken care in core

Changes in v2:
- move pci1xxxx_rs485_config to a separate patch with
  pci1xxxx_rs485_supported.
---
 drivers/tty/serial/8250/8250_pci1xxxx.c | 50 +++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
index ea04c014edb9..58f47d18f7d8 100644
--- a/drivers/tty/serial/8250/8250_pci1xxxx.c
+++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
@@ -164,6 +164,54 @@ static void pci1xxxx_set_divisor(struct uart_port *port, unsigned int baud,
 	       port->membase + UART_BAUD_CLK_DIVISOR_REG);
 }
 
+static int pci1xxxx_rs485_config(struct uart_port *port,
+				 struct ktermios *termios,
+				 struct serial_rs485 *rs485)
+{
+	u32 delay_in_baud_periods;
+	u32 baud_period_in_ns;
+	u32 mode_cfg = 0;
+	u32 clock_div;
+
+	/*
+	 * pci1xxxx's uart hardware supports only RTS delay after
+	 * Tx and in units of bit times to a maximum of 15
+	 */
+	if (rs485->flags & SER_RS485_ENABLED) {
+		mode_cfg = ADCL_CFG_EN | ADCL_CFG_PIN_SEL;
+
+		if (!(rs485->flags & SER_RS485_RTS_ON_SEND))
+			mode_cfg |= ADCL_CFG_POL_SEL;
+
+		if (rs485->delay_rts_after_send) {
+			clock_div = readl(port->membase + UART_BAUD_CLK_DIVISOR_REG);
+			baud_period_in_ns =
+				FIELD_GET(BAUD_CLOCK_DIV_INT_MSK, clock_div) *
+				UART_BIT_SAMPLE_CNT;
+			delay_in_baud_periods =
+				rs485->delay_rts_after_send * NSEC_PER_MSEC /
+				baud_period_in_ns;
+			delay_in_baud_periods =
+				min_t(u32, delay_in_baud_periods,
+				      FIELD_MAX(ADCL_CFG_RTS_DELAY_MASK));
+			mode_cfg |= FIELD_PREP(ADCL_CFG_RTS_DELAY_MASK,
+					   delay_in_baud_periods);
+			rs485->delay_rts_after_send =
+				baud_period_in_ns * delay_in_baud_periods /
+				NSEC_PER_MSEC;
+		}
+	}
+	writel(mode_cfg, port->membase + ADCL_CFG_REG);
+	return 0;
+}
+
+static const struct serial_rs485 pci1xxxx_rs485_supported = {
+	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND |
+		 SER_RS485_RTS_AFTER_SEND,
+	.delay_rts_after_send = 1,
+	/* Delay RTS before send is not supported */
+};
+
 static int pci1xxxx_setup(struct pci_dev *pdev,
 			  struct uart_8250_port *port, int port_idx)
 {
@@ -174,6 +222,8 @@ static int pci1xxxx_setup(struct pci_dev *pdev,
 	port->port.set_termios = serial8250_do_set_termios;
 	port->port.get_divisor = pci1xxxx_get_divisor;
 	port->port.set_divisor = pci1xxxx_set_divisor;
+	port->port.rs485_config = pci1xxxx_rs485_config;
+	port->port.rs485_supported = pci1xxxx_rs485_supported;
 
 	ret = serial8250_pci_setup_port(pdev, port, 0, PORT_OFFSET * port_idx, 0);
 	if (ret < 0)
-- 
2.25.1

[PATCH v10 tty-next 4/4] serial: 8250_pci1xxxx: Add power management functions to quad-uart driver

[Kumaravel Thiagarajan]

pci1xxxx's quad-uart function has the capability to wake up UART
from suspend state. Enable wakeup before entering into suspend and
disable wakeup on resume.

Co-developed-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
Signed-off-by: Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>
---
Changes in v10:
- No Change

Changes in v9:
- No Change

Changes in v8:
- No Change

Changes in v7:
- No Change

Changes in v6:
- No Change

Changes in v5:
- Corrected commit message

Changes in v4:
- No Change

Changes in v3:
- Handled race condition in suspend and resume callbacks

Changes in v2:
- Use DEFINE_SIMPLE_DEV_PM_OPS instead of SIMPLE_DEV_PM_OPS.
- Use pm_sleep_ptr instead of CONFIG_PM_SLEEP.
- Change the return data type of pci1xxxx_port_suspend to bool from int.
---
 drivers/tty/serial/8250/8250_pci1xxxx.c | 115 ++++++++++++++++++++++++
 1 file changed, 115 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c
index 58f47d18f7d8..a3b25779d921 100644
--- a/drivers/tty/serial/8250/8250_pci1xxxx.c
+++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
@@ -212,6 +212,116 @@ static const struct serial_rs485 pci1xxxx_rs485_supported = {
 	/* Delay RTS before send is not supported */
 };
 
+static bool pci1xxxx_port_suspend(int line)
+{
+	struct uart_8250_port *up = serial8250_get_port(line);
+	struct uart_port *port = &up->port;
+	struct tty_port *tport = &port->state->port;
+	unsigned long flags;
+	bool ret = false;
+	u8 wakeup_mask;
+
+	mutex_lock(&tport->mutex);
+	if (port->suspended == 0 && port->dev) {
+		wakeup_mask = readb(up->port.membase + UART_WAKE_MASK_REG);
+
+		spin_lock_irqsave(&port->lock, flags);
+		port->mctrl &= ~TIOCM_OUT2;
+		port->ops->set_mctrl(port, port->mctrl);
+		spin_unlock_irqrestore(&port->lock, flags);
+
+		ret = (wakeup_mask & UART_WAKE_SRCS) != UART_WAKE_SRCS;
+	}
+
+	writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG);
+	mutex_unlock(&tport->mutex);
+
+	return ret;
+}
+
+static void pci1xxxx_port_resume(int line)
+{
+	struct uart_8250_port *up = serial8250_get_port(line);
+	struct uart_port *port = &up->port;
+	struct tty_port *tport = &port->state->port;
+	unsigned long flags;
+
+	mutex_lock(&tport->mutex);
+	writeb(UART_BLOCK_SET_ACTIVE, port->membase + UART_ACTV_REG);
+	writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG);
+
+	if (port->suspended == 0) {
+		spin_lock_irqsave(&port->lock, flags);
+		port->mctrl |= TIOCM_OUT2;
+		port->ops->set_mctrl(port, port->mctrl);
+		spin_unlock_irqrestore(&port->lock, flags);
+	}
+	mutex_unlock(&tport->mutex);
+}
+
+static int pci1xxxx_suspend(struct device *dev)
+{
+	struct pci1xxxx_8250 *priv = dev_get_drvdata(dev);
+	struct pci_dev *pcidev = to_pci_dev(dev);
+	bool wakeup = false;
+	unsigned int data;
+	void __iomem *p;
+	int i;
+
+	for (i = 0; i < priv->nr; i++) {
+		if (priv->line[i] >= 0) {
+			serial8250_suspend_port(priv->line[i]);
+			wakeup |= pci1xxxx_port_suspend(priv->line[i]);
+		}
+	}
+
+	p = pci_ioremap_bar(pcidev, 0);
+	if (!p) {
+		dev_err(dev, "remapping of bar 0 memory failed");
+		return -ENOMEM;
+	}
+
+	data = readl(p + UART_RESET_REG);
+	writel(data | UART_RESET_D3_RESET_DISABLE, p + UART_RESET_REG);
+
+	if (wakeup)
+		writeb(UART_PCI_CTRL_D3_CLK_ENABLE, p + UART_PCI_CTRL_REG);
+
+	iounmap(p);
+	device_set_wakeup_enable(dev, true);
+	pci_wake_from_d3(pcidev, true);
+
+	return 0;
+}
+
+static int pci1xxxx_resume(struct device *dev)
+{
+	struct pci1xxxx_8250 *priv = dev_get_drvdata(dev);
+	struct pci_dev *pcidev = to_pci_dev(dev);
+	unsigned int data;
+	void __iomem *p;
+	int i;
+
+	p = pci_ioremap_bar(pcidev, 0);
+	if (!p) {
+		dev_err(dev, "remapping of bar 0 memory failed");
+		return -ENOMEM;
+	}
+
+	data = readl(p + UART_RESET_REG);
+	writel(data & ~UART_RESET_D3_RESET_DISABLE, p + UART_RESET_REG);
+	iounmap(p);
+
+	for (i = 0; i < priv->nr; i++) {
+		if (priv->line[i] >= 0) {
+			pci1xxxx_port_resume(priv->line[i]);
+			serial8250_resume_port(priv->line[i]);
+		}
+	}
+
+	return 0;
+}
+
 static int pci1xxxx_setup(struct pci_dev *pdev,
 			  struct uart_8250_port *port, int port_idx)
 {
@@ -352,6 +462,8 @@ static void pci1xxxx_serial_remove(struct pci_dev *dev)
 	pci_iounmap(dev, priv->membase);
 }
 
+static DEFINE_SIMPLE_DEV_PM_OPS(pci1xxxx_pm_ops, pci1xxxx_suspend, pci1xxxx_resume);
+
 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) },
@@ -366,6 +478,9 @@ static struct pci_driver pci1xxxx_pci_driver = {
 	.name = "pci1xxxx serial",
 	.probe = pci1xxxx_serial_probe,
 	.remove = pci1xxxx_serial_remove,
+	.driver = {
+		.pm     = pm_sleep_ptr(&pci1xxxx_pm_ops),
+	},
 	.id_table = pci1xxxx_pci_tbl,
 };
 module_pci_driver(pci1xxxx_pci_driver);
-- 
2.25.1

Re: [PATCH v10 tty-next 0/4] serial: 8250_pci1xxxx: Add driver for the pci1xxxx's quad-uart function

[Greg KH]

On Sun, Dec 18, 2022 at 12:45:03AM +0530, Kumaravel Thiagarajan wrote:
> 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 patch adds device driver for the quad-uart function and
> enumerates between 1 to 4 instances of uarts based on the PCIe subsystem
> device ID.
> 
> The changes from v1->v2->v3->v4->v5->v6->v7->v8->v9->v10 are mentioned in
> each patch in the patchset.
> 
> Thanks to Andy Shevchenko, Ilpo Jarvinen, Chritophe JAILLET, Geert
> Uytterhoeven, Greg KH, Jiri Slaby for their review comments.
> 
> Kumaravel Thiagarajan (4):
>   serial: 8250_pci: Add serial8250_pci_setup_port definition in
>     8250_pcilib.c
>   serial: 8250_pci1xxxx: Add driver for quad-uart support
>   serial: 8250_pci1xxxx: Add RS485 support to quad-uart driver
>   serial: 8250_pci1xxxx: Add power management functions to quad-uart
>     driver

This doesn't apply to my tree anymore.  Can you rebase it against
Linus's latest, or linux-next and resend?

thanks,

greg k-h