Re: [PATCH v2 5/7] serial: exar: add some CTI helper functions

Ilpo Järvinen
2024-04-12T10:49:02Z

On Thu, 11 Apr 2024, parker@finest.io wrote:

> From: Parker Newman <pnewman@connecttech.com>
>
> - Adds various helper functions for CTI boards.
> - Add osc_freq and pcidev to struct exar8250
> - Added a exar_get_nr_ports function
>
> Signed-off-by: Parker Newman <pnewman@connecttech.com>
> ---
> drivers/tty/serial/8250/8250_exar.c | 363 +++++++++++++++++++++++++++-
> 1 file changed, 357 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
> index b30f3855652a..6f3697e34722 100644
> --- a/drivers/tty/serial/8250/8250_exar.c
> +++ b/drivers/tty/serial/8250/8250_exar.c
> @@ -137,6 +137,9 @@
> #define UART_EXAR_REGB_EE_ADDR_SIZE 6
> #define UART_EXAR_REGB_EE_DATA_SIZE 16
>
> +#define UART_EXAR_XR17C15X_PORT_OFFSET 0x200
> +#define UART_EXAR_XR17V25X_PORT_OFFSET 0x200
> +#define UART_EXAR_XR17V35X_PORT_OFFSET 0x400
>
> /*
> * IOT2040 MPIO wiring semantics:
> @@ -173,6 +176,46 @@
> #define IOT2040_UARTS_ENABLE 0x03
> #define IOT2040_UARTS_GPIO_HI_MODE 0xF8 /* enable & LED as outputs */
>
> +/* CTI EEPROM offsets */
> +#define CTI_EE_OFF_XR17C15X_OSC_FREQ 0x04 /* 2 words (4 bytes) */
> +#define CTI_EE_OFF_XR17V25X_OSC_FREQ 0x08 /* 2 words (4 bytes) */
> +#define CTI_EE_OFF_XR17C15X_PART_NUM 0x0A /* 4 words (8 bytes) */
> +#define CTI_EE_OFF_XR17V25X_PART_NUM 0x0E /* 4 words (8 bytes) */
> +#define CTI_EE_OFF_XR17C15X_SERIAL_NUM 0x0E /* 1 word (2 bytes) */
> +#define CTI_EE_OFF_XR17V25X_SERIAL_NUM 0x12 /* 1 word (2 bytes) */
> +#define CTI_EE_OFF_XR17V35X_SERIAL_NUM 0x11 /* 2 word (4 bytes) */
> +#define CTI_EE_OFF_XR17V35X_BOARD_FLAGS 0x13 /* 1 word (2 bytes) */

I'm not convinced but words and bytes is really needed.

> +#define CTI_EE_OFF_XR17V35X_PORT_FLAGS 0x14 /* 1 word (per port) */

There's something wrong with alignment of more than one define above.

> +
> +#define CTI_FPGA_RS485_IO_REG 0x2008
> +
> +#define CTI_DEFAULT_PCI_OSC_FREQ 29491200
> +#define CTI_DEFAULT_PCIE_OSC_FREQ 125000000
> +#define CTI_DEFAULT_FPGA_OSC_FREQ 33333333
> +
> +/*
> + * CTI Serial port line types. These match the values stored in the first
> + * nibble of the CTI EEPROM port_flags word.
> + */
> +enum cti_port_type {
> + CTI_PORT_TYPE_NONE = 0,
> + CTI_PORT_TYPE_RS232, //RS232 ONLY
> + CTI_PORT_TYPE_RS422_485, //RS422/RS485 ONLY
> + CTI_PORT_TYPE_RS232_422_485_HW, //RS232/422/485 HW ONLY Switchable
> + CTI_PORT_TYPE_RS232_422_485_SW, //RS232/422/485 SW ONLY Switchable
> + CTI_PORT_TYPE_RS232_422_485_4B, //RS232/422/485 HW/SW (4bit ex. BCG004)
> + CTI_PORT_TYPE_RS232_422_485_2B, //RS232/422/485 HW/SW (2bit ex. BBG008)
> + CTI_PORT_TYPE_MAX,
> +};
> +
> +#define CTI_PORT_TYPE_VALID(_port_type) \
> + (((_port_type) > CTI_PORT_TYPE_NONE) && \
> + ((_port_type) < CTI_PORT_TYPE_MAX))
> +
> +#define CTI_PORT_TYPE_RS485(_port_type) \
> + (((_port_type) > CTI_PORT_TYPE_RS232) && \
> + ((_port_type) < CTI_PORT_TYPE_MAX))
> +
> struct exar8250;
>
> struct exar8250_platform {
> @@ -202,6 +245,8 @@ struct exar8250_board {
>
> struct exar8250 {
> unsigned int nr;
> + unsigned int osc_freq;
> + struct pci_dev *pcidev;
> struct exar8250_board *board;
> void __iomem *virt;
> int line[];
> @@ -557,6 +602,279 @@ pci_fastcom335_setup(struct exar8250 *priv, struct pci_dev *pcidev,
> return 0;
> }
>
> +/**
> + * cti_set_tristate() - Enable/Disable RS485 transciever tristate
> + * @priv: Device's private structure
> + * @port_num: Port number to set tristate on/off
> + * @enable: Enable tristate if true, disable if false
> + *
> + * Most RS485 capable cards have a power on tristate jumper/switch that ensures
> + * the RS422/RS485 transciever does not drive a multi-drop RS485 bus when it is
> + * not the master. When this jumper is installed the user must set the RS485
> + * mode to disable tristate prior to using the port.
> + *
> + * Some Exar UARTs have an auto-tristate feature while others require setting
> + * an MPIO to disable the tristate.
> + *
> + * Return: 0 on success, negative error code on failure
> + */
> +static int cti_set_tristate(struct exar8250 *priv,
> + unsigned int port_num, bool enable)
> +{
> + int ret = 0;
> +
> + if (!priv || (port_num >= priv->nr))
> + return -EINVAL;
> +
> + //Only Exar based cards use MPIO, return 0 otherwise
> + if (priv->pcidev->vendor != PCI_VENDOR_ID_EXAR)
> + return 0;
> +
> + pci_dbg(priv->pcidev, "%s tristate for port %u\n",
> + (enable ? "enabling" : "disabling"), port_num);

dev_dbg()

Rephrasing the string slightly, you could consider using
str_enable_disable() from linux/string_choices.h

> +
> + ret = exar_mpio_set(priv, port_num, !enable);
> + if (ret)
> + return ret;
> +
> + //ensure MPIO is an output
> + ret = exar_mpio_config(priv, port_num, true);
> +
> + return ret;
> +}
> +
> +/**
> + * cti_set_plx_int_enable() - Enable/Disable PCI interrupts
> + * @priv: Device's private structure
> + * @enable: Enable interrupts if true, disable if false
> + *
> + * Some older CTI cards require MPIO_0 to be set low to enable the PCI
> + * interupts from the UART to the PLX PCI->PCIe bridge.
> + *
> + * Return: 0 on success, negative error code on failure
> + */
> +static int cti_set_plx_int_enable(struct exar8250 *priv, bool enable)
> +{
> + int ret = 0;
> +
> + if (!priv)
> + return -EINVAL;
> +
> + //Only Exar based cards use MPIO, return 0 otherwise
> + if (priv->pcidev->vendor != PCI_VENDOR_ID_EXAR)
> + return 0;
> +
> + pci_dbg(priv->pcidev, "%s plx fix\n",
> + (enable ? "enabling" : "disabling"));
> +
> + //INT enabled when MPIO0 is LOW
> + ret = exar_mpio_set(priv, 0, !enable);
> + if (ret)
> + return ret;
> +
> + //ensure MPIO is an output
> + ret = exar_mpio_config(priv, 0, true);
> +
> + return ret;
> +}
> +
> +/**
> + * cti_read_osc_freq() - Read the UART oscillator frequency from EEPROM
> + * @priv: Device's private structure

Missing second parameter.

> + *
> + * CTI XR17x15X and XR17V25X cards have the serial boards oscillator frequency
> + * stored in the EEPROM. FPGA and XR17V35X based cards use the PCI/PCIe clock.
> + *
> + * Return: frequency on success, negative error code on failure
> + */
> +static int cti_read_osc_freq(struct exar8250 *priv, uint8_t eeprom_offset)
> +{
> + int osc_freq;
> +
> + if (!priv)
> + return -EINVAL;
> +
> + osc_freq = (exar_ee_read(priv, eeprom_offset));

Unnecessary parenthesis.

> + osc_freq |= (exar_ee_read(priv, (eeprom_offset + 1)) << 16);

Add the field #define with GENMASK() and use FIELD_PREP() here? Perhaps
both lines should use FIELD_PREP() even if one of them has 0 shift.

> +
> + //check if EEPROM word was blank
> + if ((osc_freq == 0xFFFF) || (osc_freq == 0x0000))
> + return -EIO;
> +
> + pci_dbg(priv->pcidev, "osc_freq from EEPROM %d\n", osc_freq);
> +
> + return osc_freq;
> +}
> +
> +/**
> + * cti_get_port_type_xr17c15x_xr17v25x() - Get the port type of a xr17c15x
> + * or xr17v25x card

I suppose this shorter version would be enough to provide the same amount
information:

Get the port type of xr17c15x/xr17v25x

> + *

No empty line.

> + * @priv: Device's private structure
> + * @port_num: Port to get type of
> + *
> + * CTI xr17c15x and xr17v25x based cards port types are based on PCI IDs
> + *
> + * Return: port type on success, CTI_PORT_TYPE_NONE on failure
> + */
> +static enum cti_port_type cti_get_port_type_xr17c15x_xr17v25x(struct exar8250 *priv,
> + unsigned int port_num)
> +{
> + enum cti_port_type port_type;
> +
> + if (!priv)
> + return CTI_PORT_TYPE_NONE;

Can this happen?

> + switch (priv->pcidev->subsystem_device) {
> + //RS232 only cards
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_232:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_232:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_232:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_232:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_232_NS:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_232:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_232_NS:
> + port_type = CTI_PORT_TYPE_RS232;
> + break;
> + //1x RS232, 1x RS422/RS485
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_1_1:
> + port_type = (port_num == 0) ?
> + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> + break;
> + //2x RS232, 2x RS422/RS485
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_2:
> + port_type = (port_num < 2) ?
> + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> + break;
> + //4x RS232, 4x RS422/RS485
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4_SP:
> + port_type = (port_num < 4) ?
> + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> + break;
> + //RS232/RS422/RS485 HW (jumper) selectable
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_SP_OPTO:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_SP_OPTO_A:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_SP_OPTO_B:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XPRS:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_A:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_B:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_16_XPRS_A:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_16_XPRS_B:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XPRS_OPTO:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_OPTO_A:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XPRS_OPTO_B:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XP_OPTO_LEFT:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_XP_OPTO_RIGHT:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_XP_OPTO:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_4_XPRS_OPTO:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP:
> + port_type = CTI_PORT_TYPE_RS232_422_485_HW;
> + break;
> + //RS422/RS485 HW (jumper) selectable
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_485:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_4_485:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_485:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_SP_485:
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_8_XPRS_LP_485:
> + port_type = CTI_PORT_TYPE_RS422_485;
> + break;
> + //6x RS232, 2x RS422/RS485
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_6_2_SP:
> + port_type = (port_num < 6) ?
> + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> + break;
> + //2x RS232, 6x RS422/RS485
> + case PCI_SUBDEVICE_ID_CONNECT_TECH_PCI_UART_2_6_SP:
> + port_type = (port_num < 2) ?
> + CTI_PORT_TYPE_RS232 : CTI_PORT_TYPE_RS422_485;
> + break;
> + default:
> + pci_err(priv->pcidev, "unknown/unsupported device\n");
> + port_type = CTI_PORT_TYPE_NONE;
> + }
> +
> + return port_type;
> +}
> +
> +/**
> + * cti_get_port_type_fpga() - Get the port type of a CTI FPGA card
> + * @priv: Device's private structure
> + * @port_num: Port to get type of
> + *
> + * FPGA based cards port types are based on PCI IDs
> + *
> + * Return: port type on success, CTI_PORT_TYPE_NONE on failure
> + */
> +static enum cti_port_type cti_get_port_type_fpga(struct exar8250 *priv,
> + unsigned int port_num)
> +{
> + enum cti_port_type port_type;
> +
> + if (!priv)
> + return CTI_PORT_TYPE_NONE;
> +
> + switch (priv->pcidev->device) {
> + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_12_XIG00X:
> + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_12_XIG01X:
> + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_16:
> + port_type = CTI_PORT_TYPE_RS232_422_485_HW;
> + break;
> + default:
> + pci_err(priv->pcidev, "unknown/unsupported device\n");

dev_err()

> + return CTI_PORT_TYPE_NONE;
> + }
> +
> + return port_type;
> +}
> +
> +/**
> + * cti_get_port_type_xr17v35x() - Read port type from the EEPROM
> + * @priv: Device's private structure
> + * @port_num: port offset
> + *
> + * CTI XR17V35X based cards have the port types stored in the EEPROM.
> + * This function reads the port type for a single port.
> + *
> + * Return: port type on success, CTI_PORT_TYPE_NONE on failure
> + */
> +static enum cti_port_type cti_get_port_type_xr17v35x(struct exar8250 *priv,
> + unsigned int port_num)
> +{
> + uint16_t port_flags;
> + uint8_t offset;
> + enum cti_port_type port_type;
> +
> + if (!priv)
> + return CTI_PORT_TYPE_NONE;
> +
> + offset = CTI_EE_OFF_XR17V35X_PORT_FLAGS + port_num;
> + port_flags = exar_ee_read(priv, offset);
> +
> + port_type = (port_flags & 0x00FF);

Add named define with GENMASK() and use FIELD_GET()

> +
> + if (!CTI_PORT_TYPE_VALID(port_type)) {
> + /*
> + * If the port type is missing the card assume it is a
> + * RS232/RS422/RS485 card to be safe.
> + *
> + * There is one known board (BEG013) that only has
> + * 3 of 4 port types written to the EEPROM so this
> + * acts as a work around.
> + */
> + pci_warn(priv->pcidev,

dev_warn(). Please fix all pci_xx() logging, I won't flag them from this
point onwards.

> + "failed to get port %d type from EEPROM\n", port_num);
> + port_type = CTI_PORT_TYPE_RS232_422_485_HW;
> + }
> +
> + return port_type;
> +}
> +
> static int
> pci_connect_tech_setup(struct exar8250 *priv, struct pci_dev *pcidev,
> struct uart_8250_port *port, int idx)
> @@ -914,6 +1232,39 @@ static irqreturn_t exar_misc_handler(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +static unsigned int exar_get_nr_ports(struct exar8250_board *board,
> + struct pci_dev *pcidev)
> +{
> + unsigned int nr_ports = 0;
> +
> + if (!board || !pcidev)
> + return 0;
> +
> + if (pcidev->vendor == PCI_VENDOR_ID_ACCESSIO) {
> + nr_ports = BIT(((pcidev->device & 0x38) >> 3) - 1);
> + } else if (board->num_ports > 0) {
> + //Check if board struct overrides number of ports
> + nr_ports = board->num_ports;
> + } else if (pcidev->vendor == PCI_VENDOR_ID_EXAR) {
> + //Exar encodes # ports in last nibble of PCI Device ID ex. 0358
> + nr_ports = pcidev->device & 0x0f;
> + } else if (pcidev->vendor == PCI_VENDOR_ID_CONNECT_TECH) {
> + //Handle CTI FPGA cards
> + switch (pcidev->device) {
> + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_12_XIG00X:
> + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_12_XIG01X:
> + nr_ports = 12;
> + break;
> + case PCI_DEVICE_ID_CONNECT_TECH_PCI_XR79X_16:
> + nr_ports = 16;
> + default:
> + break;
> + }
> + }
> +
> + return nr_ports;
> +}
> +
> static int
> exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent)
> {
> @@ -933,18 +1284,18 @@ exar_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *ent)
>
> maxnr = pci_resource_len(pcidev, bar) >> (board->reg_shift + 3);
>
> - if (pcidev->vendor == PCI_VENDOR_ID_ACCESSIO)
> - nr_ports = BIT(((pcidev->device & 0x38) >> 3) - 1);
> - else if (board->num_ports)
> - nr_ports = board->num_ports;
> - else
> - nr_ports = pcidev->device & 0x0f;
> + nr_ports = exar_get_nr_ports(board, pcidev);
> + if (nr_ports == 0) {

Can you please do this refactoring in a preparatory patch, and only add
the new stuff in this patch into exar_get_nr_ports() patch.

--
i.

> + pci_err(pcidev, "failed to get number of ports\n");
> + return -ENODEV;
> + }
>
> priv = devm_kzalloc(&pcidev->dev, struct_size(priv, line, nr_ports), GFP_KERNEL);
> if (!priv)
> return -ENOMEM;
>
> priv->board = board;
> + priv->pcidev = pcidev;
> priv->virt = pcim_iomap(pcidev, bar, 0);
> if (!priv->virt)
> return -ENOMEM;
> --
> 2.43.2
>
>