[PATCH V3 3/4] ARM64 LPC: support serial based on low-pin-count

From: Zhichang Yuan
Date: Wed Sep 14 2016 - 08:00:23 EST

From: "zhichang.yuan" <yuanzhichang@xxxxxxxxxxxxx>

On Hip06 platform, a 16550 compatible UART is connected to low-pin-count and
controlled through the LPC I/O cycles. After registering the LPC uart specific
serial_in/serial_out to 8250 core driver, serial data can be read/written
through the LPC.

Signed-off-by: zhichang.yuan <yuanzhichang@xxxxxxxxxxxxx>
---
.../devicetree/bindings/serial/hisi-lpc-uart.txt | 60 ++++++++
drivers/tty/serial/8250/8250_hisi_lpc.c | 171 +++++++++++++++++++++
drivers/tty/serial/8250/Kconfig | 9 ++
drivers/tty/serial/8250/Makefile | 1 +
4 files changed, 241 insertions(+)
create mode 100644 Documentation/devicetree/bindings/serial/hisi-lpc-uart.txt
create mode 100644 drivers/tty/serial/8250/8250_hisi_lpc.c

diff --git a/Documentation/devicetree/bindings/serial/hisi-lpc-uart.txt b/Documentation/devicetree/bindings/serial/hisi-lpc-uart.txt
new file mode 100644
index 0000000..0f8ec2a
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/hisi-lpc-uart.txt
@@ -0,0 +1,60 @@
+* Hisilicon hip06 UART through low-pin-count
+
+Required properties:
+- compatible : "hisilicon,lpc-uart"
+- reg : offset and length of the I/O port set for the device.
+- reg-names : name the uart resources.
+ "lpc_mem" represents memory resource of the LPC parent. When
+ flat-tree earlycon is needed, this memory resource and
+ resource name are mandatory. Otherwise they are optional;
+ "dev_io" represents I/O resource of this device. It is
+ mandatory to access this device;
+
+Clock handling:
+ The clock rate of this device is same as the 8250 default clock rate, that
+ is 1843200. No need to define the clock rate in device tree.
+
+Note:
+ This device depends on its parent device whose compatible string is
+ "hisilicon,low-pin-count".
+
+ The format of "reg" property follows the I/O space definition in ISA/EISA
+ binding specification linked to:
+ http://www.firmware.org/1275/bindings/isa/isa0_4d.ps
+
+Example:
+
+ uart0: lpc-uart@2f8 {
+ compatible = "hisilicon,lpc-uart";
+ reg = <0x01 0x2f8 0x08>;
+ status = "disabled";
+ };
+
+
+Example with low-pin-count parent device:
+
+ isa@a01b0000 {
+ compatible = "hisilicon,low-pin-count";
+ #address-cells = <2>;
+ #size-cells = <1>;
+ reg = <0x0 0xa01b0000 0x0 0x1000>;
+ ranges = <0x00 0xa01b0000 0x00 0xa01b0000 0x1000>,
+ <0x01 0xe4 0x0 0xe4 0x04>,
+ <0x01 0x2f8 0x0 0x2f8 0x08>;
+
+ ipmi0: bt@e4 {
+ compatible = "ipmi-bt";
+ device_type = "ipmi";
+ reg = <0x01 0xe4 0x04>;
+ reg-names = "dev_io";
+ status = "disabled";
+ };
+
+ uart0: lpc-uart@2f8 {
+ compatible = "hisilicon,lpc-uart";
+ reg = <0x00 0xa01b0000 0x1000>,
+ <0x01 0x2f8 0x08>;
+ ret-names = "lpc_mem", "dev_io";
+ status = "disabled";
+ };
+ };
diff --git a/drivers/tty/serial/8250/8250_hisi_lpc.c b/drivers/tty/serial/8250/8250_hisi_lpc.c
new file mode 100644
index 0000000..a8ba1ca
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_hisi_lpc.c
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2016 Hisilicon Limited, All Rights Reserved.
+ * Author: Zhichang Yuan <yuanzhichang@xxxxxxxxxxxxx>
+ * Author: Zou Rongrong <@huawei.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/serial_8250.h>
+#include <asm-generic/serial.h>
+#include <linux/of_address.h>
+
+
+/**
+ * hisilpc_serial_inb - read/input data from the designated serial port.
+ * @p: the serial port where the data read from
+ * @offset: the target I/O port address where the read is from
+ *
+ * Returns the byte data from this serial port.
+ * -1 means some failures.
+ *
+ */
+static unsigned int hisilpc_serial_inb(struct uart_port *p, int offset)
+{
+ struct extio_ops *parentops;
+
+ parentops = p->private_data;
+ if (!parentops || !parentops->pfin)
+ return -1;
+
+ return parentops->pfin(parentops->devpara,
+ p->iobase + (offset << p->regshift),
+ NULL, sizeof(u8), 1);
+}
+
+/**
+ * hisilpc_serial_outb - write/output data from the designated serial port.
+ * @p: the serial port where the data is written to
+ * @offset: the target I/O port address where the write is from
+ *
+ */
+static void hisilpc_serial_outb(struct uart_port *p, int offset, int value)
+{
+ struct extio_ops *parentops;
+
+ parentops = p->private_data;
+ if (!parentops || !parentops->pfout)
+ return;
+
+ parentops->pfout(parentops->devpara,
+ p->iobase + (offset << p->regshift),
+ &value, sizeof(u8), 1);
+}
+
+
+static int hisilpc8250_probe(struct platform_device *pdev)
+{
+ struct uart_8250_port uart = {};
+ struct uart_port *port = &uart.port;
+ int err = 0;
+ struct resource *iores;
+ struct extio_ops *platdata;
+
+ if (!pdev->dev.parent)
+ return -ENODEV;
+ dev_info(&pdev->dev, "##probe entering\n");
+
+ /* To support the earlycon in bootargs, the first reg must be MEM */
+ iores = platform_get_resource_byname(pdev, IORESOURCE_IO,
+ "dev_io");
+ if (!iores) {
+ dev_err(&pdev->dev, "can not find the IO0\n");
+ return -ENXIO;
+ }
+
+ /*
+ * save the platform data from parent in uart_port for serial_in,
+ * serial_out
+ */
+ platdata = dev_get_platdata(&pdev->dev);
+ port->private_data = (void *)platdata;
+ if (!port->private_data) {
+ dev_err(&pdev->dev, "no platform data!\n");
+ return -ENODEV;
+ }
+
+ if (platdata->start != iores->start || platdata->end != iores->end) {
+ dev_err(&pdev->dev, "PIO range[0x%lx - %lx] isn't fit!\n",
+ (unsigned long)iores->start,
+ (unsigned long)iores->end);
+ return -ENXIO;
+ }
+ port->iobase = (unsigned long)iores->start + platdata->ptoffset;
+ dev_info(&pdev->dev, "real port start is 0x%lx\n", port->iobase);
+
+ port->irq = 0;
+ port->flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
+ port->dev = &pdev->dev;
+ port->iotype = UPIO_PORT;
+ port->regshift = 0;
+ port->uartclk = BASE_BAUD * 16;
+
+ spin_lock_init(&port->lock);
+
+ port->serial_in = hisilpc_serial_inb;
+ port->serial_out = hisilpc_serial_outb;
+
+ err = serial8250_register_8250_port(&uart);
+ if (err < 0) {
+ dev_err(&pdev->dev, "register uart FAIL(%d)!\n", -err);
+ return err;
+ }
+
+ platform_set_drvdata(pdev, (void *)&err);
+ dev_info(&pdev->dev, "##probing OK(%d)\n", err);
+ return 0;
+}
+
+static int hisilpc8250_remove(struct platform_device *pdev)
+{
+ int line = *((int *)platform_get_drvdata(pdev));
+
+ serial8250_unregister_port(line);
+
+ return 0;
+}
+
+
+static const struct of_device_id hs8250_of_match[] = {
+ { .compatible = "hisilicon,lpc-uart" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, hs8250_of_match);
+
+static const struct acpi_device_id hs8250_acpi_match[] = {
+ /*{ "PNP0501", 0 },*/
+ { "HISI1031", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, hs8250_acpi_match);
+
+static struct platform_driver hs_lpc8250_driver = {
+ .driver = {
+ .name = "hisi-lpc-uart",
+ .of_match_table = hs8250_of_match,
+ .acpi_match_table = ACPI_PTR(hs8250_acpi_match),
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
+ .probe = hisilpc8250_probe,
+ .remove = hisilpc8250_remove,
+};
+
+module_platform_driver(hs_lpc8250_driver);
+
+
+MODULE_AUTHOR("Rongrong Zou");
+MODULE_DESCRIPTION("8250 serial probe module for Hisilicon LPC UART");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("v1.0");
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 7c6f7af..c2e42f7 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -246,6 +246,15 @@ config SERIAL_8250_HUB6
To compile this driver as a module, choose M here: the module
will be called 8250_hub6.

+config SERIAL_8250_HISI_LPC
+ tristate "Support Hisilicon Hip0X UART through LPC"
+ depends on SERIAL_8250 !=n && HISILICON_LPC
+ help
+ Say Y here if you have a hip06 board.
+
+ To compile this driver as a module, choose M here: the module
+ will be called 8250_hisi_lpc.
+
#
# Misc. options/drivers.
#
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index 367d403..1f2915b 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -21,6 +21,7 @@ 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_FSL) += 8250_fsl.o
+obj-$(CONFIG_SERIAL_8250_HISI_LPC) += 8250_hisi_lpc.o
obj-$(CONFIG_SERIAL_8250_DW) += 8250_dw.o
obj-$(CONFIG_SERIAL_8250_EM) += 8250_em.o
obj-$(CONFIG_SERIAL_8250_OMAP) += 8250_omap.o
--
1.9.1