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From: Antony Pavlov <antonynpavlov@gmail.com>
To: barebox@lists.infradead.org
Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: [PATCH 2/8] serial: add litex UART driver
Date: Tue, 17 Aug 2021 13:04:29 +0300
Message-ID: <20210817100435.114756-3-antonynpavlov@gmail.com> (raw)
In-Reply-To: <20210817100435.114756-1-antonynpavlov@gmail.com>

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/serial/Makefile       |  1 +
 drivers/serial/serial_litex.c | 96 +++++++++++++++++++++++++++++++++++
 2 files changed, 97 insertions(+)

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 5120b17376..45055371ea 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_DRIVER_SERIAL_DIGIC)		+= serial_digic.o
 obj-$(CONFIG_DRIVER_SERIAL_LPUART)		+= serial_lpuart.o
 obj-$(CONFIG_VIRTIO_CONSOLE)			+= virtio_console.o
 obj-$(CONFIG_SERIAL_SIFIVE)			+= serial_sifive.o
+obj-$(CONFIG_SOC_LITEX)				+= serial_litex.o
diff --git a/drivers/serial/serial_litex.c b/drivers/serial/serial_litex.c
new file mode 100644
index 0000000000..8562a45ecc
--- /dev/null
+++ b/drivers/serial/serial_litex.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+
+#define UART_RXTX	0x00
+#define UART_TXFULL	0x04
+#define UART_RXEMPTY	0x08
+#define UART_EV_PENDING	0x10
+#define  UART_EV_RX	(1 << 1)
+
+static inline uint32_t litex_serial_readb(struct console_device *cdev,
+						uint32_t offset)
+{
+	void __iomem *base = cdev->dev->priv;
+
+	return readb(base + offset);
+}
+
+static inline void litex_serial_writeb(struct console_device *cdev,
+					uint32_t value, uint32_t offset)
+{
+	void __iomem *base = cdev->dev->priv;
+
+	writeb(value, base + offset);
+}
+
+static void litex_serial_putc(struct console_device *cdev, char c)
+{
+	while (litex_serial_readb(cdev, UART_TXFULL))
+		;
+
+	litex_serial_writeb(cdev, c, UART_RXTX);
+}
+
+static int litex_serial_getc(struct console_device *cdev)
+{
+	int c;
+
+	while (litex_serial_readb(cdev, UART_RXEMPTY))
+		;
+
+	c = litex_serial_readb(cdev, UART_RXTX);
+
+	/* refresh UART_RXEMPTY by writing UART_EV_RX to UART_EV_PENDING */
+	litex_serial_writeb(cdev, UART_EV_RX, UART_EV_PENDING);
+
+	return c;
+}
+
+static int litex_serial_tstc(struct console_device *cdev)
+{
+	return !litex_serial_readb(cdev, UART_RXEMPTY);
+}
+
+static int litex_serial_probe(struct device_d *dev)
+{
+	struct resource *iores;
+	struct console_device *cdev;
+
+	cdev = xzalloc(sizeof(struct console_device));
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+
+	dev->priv = IOMEM(iores->start);
+	cdev->dev = dev;
+	cdev->tstc = &litex_serial_tstc;
+	cdev->putc = &litex_serial_putc;
+	cdev->getc = &litex_serial_getc;
+	cdev->setbrg = NULL;
+
+	console_register(cdev);
+
+	return 0;
+}
+
+static __maybe_unused struct of_device_id litex_serial_dt_ids[] = {
+	{
+		.compatible = "litex,uart",
+	}, {
+		/* sentinel */
+	}
+};
+
+static struct driver_d litex_serial_driver = {
+	.name  = "litex-uart",
+	.probe = litex_serial_probe,
+	.of_compatible = DRV_OF_COMPAT(litex_serial_dt_ids),
+};
+console_platform_driver(litex_serial_driver);
-- 
2.32.0


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  parent reply	other threads:[~2021-08-17 10:07 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17 10:04 [PATCH 0/8 v4] RISC-V: add LiteX SoC support Antony Pavlov
2021-08-17 10:04 ` [PATCH 1/8] clocksource: timer-riscv: select CSR from device tree Antony Pavlov
2021-08-17 10:04 ` Antony Pavlov [this message]
2021-08-17 10:04 ` [PATCH 3/8] console: support set baudrate for fixed baudrate drivers Antony Pavlov
2021-08-17 10:04 ` [PATCH 4/8] gpio: add driver for 74xx-ICs with MMIO access Antony Pavlov
2021-08-17 10:04 ` [PATCH 5/8] spi: add litex spiflash driver Antony Pavlov
2021-08-17 10:04 ` [PATCH 6/8] net: add LiteEth driver Antony Pavlov
2021-08-17 10:04 ` [PATCH 7/8] RISC-V: add LiteX SoC and linux-on-litex-vexriscv support Antony Pavlov
2021-08-17 10:04 ` [PATCH 8/8] RISC-V: add litex_linux_defconfig Antony Pavlov
2021-08-17 10:10 ` [PATCH 0/8 v4] RISC-V: add LiteX SoC support Antony Pavlov

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