Merge branch 'master' into openslxopenslx

2 files changed, 306 insertions, 0 deletions

diff --git a/src/drivers/uart/dwuart.c b/src/drivers/uart/dwuart.c
new file mode 100644
index 000000000..ce08e8ebf
--- /dev/null
+++ b/src/drivers/uart/dwuart.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * DesignWare UART
+ *
+ */
+
+#include <errno.h>
+#include <ipxe/uart.h>
+#include <ipxe/ns16550.h>
+#include <ipxe/devtree.h>
+#include <ipxe/fdt.h>
+
+/**
+ * Probe devicetree device
+ *
+ * @v dt		Devicetree device
+ * @v offset		Starting node offset
+ * @ret rc		Return status code
+ */
+static int dwuart_probe ( struct dt_device *dt, unsigned int offset ) {
+	struct ns16550_uart *ns16550;
+	struct uart *uart;
+	uint32_t shift;
+	uint32_t clock;
+	int rc;
+
+	/* Allocate and initialise UART */
+	uart = alloc_uart ( sizeof ( *ns16550 ) );
+	if ( ! uart ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+	uart->name = dt->name;
+	uart->op = &ns16550_operations;
+	ns16550 = uart->priv;
+	dt_set_drvdata ( dt, uart );
+
+	/* Map registers */
+	ns16550->base = dt_ioremap ( dt, offset, 0, 0 );
+	if ( ! ns16550->base ) {
+		rc = -ENODEV;
+		goto err_ioremap;
+	}
+
+	/* Get register shift */
+	if ( ( rc = fdt_u32 ( &sysfdt, offset, "reg-shift", &shift ) ) != 0 )
+		shift = 0;
+	ns16550->shift = shift;
+
+	/* Get clock rate */
+	if ( ( rc = fdt_u32 ( &sysfdt, offset, "clock-frequency",
+			      &clock ) ) != 0 ) {
+		clock = NS16550_CLK_DEFAULT;
+	}
+	ns16550->clock = clock;
+
+	/* Register UART */
+	if ( ( rc = uart_register ( uart ) ) != 0 )
+		goto err_register;
+
+	return 0;
+
+	uart_unregister ( uart );
+ err_register:
+	iounmap ( ns16550->base );
+ err_ioremap:
+	uart_nullify ( uart );
+	uart_put ( uart );
+ err_alloc:
+	return rc;
+}
+
+/**
+ * Remove devicetree device
+ *
+ * @v dt		Devicetree device
+ */
+static void dwuart_remove ( struct dt_device *dt ) {
+	struct uart *uart = dt_get_drvdata ( dt );
+	struct ns16550_uart *ns16550 = uart->priv;
+
+	/* Unregister UART */
+	uart_unregister ( uart );
+
+	/* Free UART */
+	iounmap ( ns16550->base );
+	uart_nullify ( uart );
+	uart_put ( uart );
+}
+
+/** DesignWare UART compatible model identifiers */
+static const char * dwuart_ids[] = {
+	"snps,dw-apb-uart",
+	"ns16550a",
+};
+
+/** DesignWare UART devicetree driver */
+struct dt_driver dwuart_driver __dt_driver = {
+	.name = "dwuart",
+	.ids = dwuart_ids,
+	.id_count = ( sizeof ( dwuart_ids ) / sizeof ( dwuart_ids[0] ) ),
+	.probe = dwuart_probe,
+	.remove = dwuart_remove,
+};
diff --git a/src/drivers/uart/ns16550.c b/src/drivers/uart/ns16550.c
new file mode 100644
index 000000000..f00e834b4
--- /dev/null
+++ b/src/drivers/uart/ns16550.c
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2025 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * 16550-compatible UART
+ *
+ */
+
+#include <unistd.h>
+#include <errno.h>
+#include <ipxe/uart.h>
+#include <ipxe/ns16550.h>
+
+/** Timeout for transmit holding register to become empty */
+#define NS16550_THRE_TIMEOUT_MS 100
+
+/** Timeout for transmitter to become empty */
+#define NS16550_TEMT_TIMEOUT_MS 1000
+
+/**
+ * Transmit data
+ *
+ * @v uart		UART
+ * @v data		Data
+ */
+static void ns16550_transmit ( struct uart *uart, uint8_t data ) {
+	struct ns16550_uart *ns16550 = uart->priv;
+	unsigned int i;
+	uint8_t lsr;
+
+	/* Wait for transmitter holding register to become empty */
+	for ( i = 0 ; i < NS16550_THRE_TIMEOUT_MS ; i++ ) {
+		lsr = ns16550_read ( ns16550, NS16550_LSR );
+		if ( lsr & NS16550_LSR_THRE )
+			break;
+		mdelay ( 1 );
+	}
+
+	/* Transmit data (even if we timed out) */
+	ns16550_write ( ns16550, NS16550_THR, data );
+}
+
+/**
+ * Check if data is ready
+ *
+ * @v uart		UART
+ * @ret ready		Data is ready
+ */
+static int ns16550_data_ready ( struct uart *uart ) {
+	struct ns16550_uart *ns16550 = uart->priv;
+	uint8_t lsr;
+
+	/* Check for receive data ready */
+	lsr = ns16550_read ( ns16550, NS16550_LSR );
+	return ( lsr & NS16550_LSR_DR );
+}
+
+/**
+ * Receive data
+ *
+ * @v uart		UART
+ * @ret data		Data
+ */
+static uint8_t ns16550_receive ( struct uart *uart ) {
+	struct ns16550_uart *ns16550 = uart->priv;
+	uint8_t rbr;
+
+	/* Receive byte */
+	rbr = ns16550_read ( ns16550, NS16550_RBR );
+	return rbr;
+}
+
+/**
+ * Flush transmitted data
+ *
+ * @v uart		UART
+ */
+static void ns16550_flush ( struct uart *uart ) {
+	struct ns16550_uart *ns16550 = uart->priv;
+	unsigned int i;
+	uint8_t lsr;
+
+	/* Wait for transmitter to become empty */
+	for ( i = 0 ; i < NS16550_TEMT_TIMEOUT_MS ; i++ ) {
+		lsr = ns16550_read ( ns16550, NS16550_LSR );
+		if ( lsr & NS16550_LSR_TEMT )
+			break;
+	}
+}
+
+/**
+ * Initialise UART
+ *
+ * @v uart		UART
+ * @ret rc		Return status code
+ */
+static int ns16550_init ( struct uart *uart ) {
+	struct ns16550_uart *ns16550 = uart->priv;
+	uint8_t dlm;
+	uint8_t dll;
+
+	/* Fail if UART scratch register seems not to be present */
+	ns16550_write ( ns16550, NS16550_SCR, 0x18 );
+	if ( ns16550_read ( ns16550, NS16550_SCR ) != 0x18 )
+		return -ENODEV;
+	ns16550_write ( ns16550, NS16550_SCR, 0xae );
+	if ( ns16550_read ( ns16550, NS16550_SCR ) != 0xae )
+		return -ENODEV;
+
+	/* Wait for UART to become idle before modifying LCR */
+	ns16550_flush ( uart );
+
+	/* Configure divisor and line control register, if applicable */
+	ns16550_write ( ns16550, NS16550_LCR,
+			( NS16550_LCR_8N1 | NS16550_LCR_DLAB ) );
+	if ( uart->baud ) {
+		ns16550->divisor = ( ( ns16550->clock / uart->baud ) /
+				     NS16550_CLK_BIT );
+		dlm = ( ( ns16550->divisor >> 8 ) & 0xff );
+		dll = ( ( ns16550->divisor >> 0 ) & 0xff );
+		ns16550_write ( ns16550, NS16550_DLM, dlm );
+		ns16550_write ( ns16550, NS16550_DLL, dll );
+	} else {
+		dlm = ns16550_read ( ns16550, NS16550_DLM );
+		dll = ns16550_read ( ns16550, NS16550_DLL );
+		ns16550->divisor = ( ( dlm << 8 ) | dll );
+	}
+	ns16550_write ( ns16550, NS16550_LCR, NS16550_LCR_8N1 );
+
+	/* Disable interrupts */
+	ns16550_write ( ns16550, NS16550_IER, 0 );
+
+	/* Enable FIFOs */
+	ns16550_write ( ns16550, NS16550_FCR, NS16550_FCR_FE );
+
+	/* Assert DTR and RTS */
+	ns16550_write ( ns16550, NS16550_MCR,
+			( NS16550_MCR_DTR | NS16550_MCR_RTS ) );
+
+	/* Flush any stale received data */
+	while ( ns16550_data_ready ( uart ) )
+		ns16550_receive ( uart );
+
+	return 0;
+}
+
+/** 16550 UART operations */
+struct uart_operations ns16550_operations = {
+	.transmit = ns16550_transmit,
+	.data_ready = ns16550_data_ready,
+	.receive = ns16550_receive,
+	.init = ns16550_init,
+	.flush = ns16550_flush,
+};