These changes are the raw update to qemu-2.6.

[kvmfornfv.git] / qemu / roms / ipxe / src / core / uart.c

diff --git a/qemu/roms/ipxe/src/core/uart.c b/qemu/roms/ipxe/src/core/uart.c
new file mode 100644 (file)
index 0000000..b85fe07
--- /dev/null
+++ b/qemu/roms/ipxe/src/core/uart.c
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2014 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>
+
+/** Timeout for transmit holding register to become empty */
+#define UART_THRE_TIMEOUT_MS 100
+
+/** Timeout for transmitter to become empty */
+#define UART_TEMT_TIMEOUT_MS 1000
+
+/**
+ * Transmit data
+ *
+ * @v uart             UART
+ * @v data             Data
+ */
+void uart_transmit ( struct uart *uart, uint8_t data ) {
+       unsigned int i;
+       uint8_t lsr;
+
+       /* Wait for transmitter holding register to become empty */
+       for ( i = 0 ; i < UART_THRE_TIMEOUT_MS ; i++ ) {
+               lsr = uart_read ( uart, UART_LSR );
+               if ( lsr & UART_LSR_THRE )
+                       break;
+               mdelay ( 1 );
+       }
+
+       /* Transmit data (even if we timed out) */
+       uart_write ( uart, UART_THR, data );
+}
+
+/**
+ * Flush data
+ *
+ * @v uart             UART
+ */
+void uart_flush ( struct uart *uart ) {
+       unsigned int i;
+       uint8_t lsr;
+
+       /* Wait for transmitter and receiver to become empty */
+       for ( i = 0 ; i < UART_TEMT_TIMEOUT_MS ; i++ ) {
+               uart_read ( uart, UART_RBR );
+               lsr = uart_read ( uart, UART_LSR );
+               if ( ( lsr & UART_LSR_TEMT ) && ! ( lsr & UART_LSR_DR ) )
+                       break;
+       }
+}
+
+/**
+ * Check for existence of UART
+ *
+ * @v uart             UART
+ * @ret rc             Return status code
+ */
+int uart_exists ( struct uart *uart ) {
+
+       /* Fail if no UART port is defined */
+       if ( ! uart->base )
+               return -ENODEV;
+
+       /* Fail if UART scratch register seems not to be present */
+       uart_write ( uart, UART_SCR, 0x18 );
+       if ( uart_read ( uart, UART_SCR ) != 0x18 )
+               return -ENODEV;
+       uart_write ( uart, UART_SCR, 0xae );
+       if ( uart_read ( uart, UART_SCR ) != 0xae )
+               return -ENODEV;
+
+       return 0;
+}
+
+/**
+ * Initialise UART
+ *
+ * @v uart             UART
+ * @v baud             Baud rate, or zero to leave unchanged
+ * @v lcr              Line control register value, or zero to leave unchanged
+ * @ret rc             Return status code
+ */
+int uart_init ( struct uart *uart, unsigned int baud, uint8_t lcr ) {
+       uint8_t dlm;
+       uint8_t dll;
+       int rc;
+
+       /* Check for existence of UART */
+       if ( ( rc = uart_exists ( uart ) ) != 0 )
+               return rc;
+
+       /* Configure divisor and line control register, if applicable */
+       if ( ! lcr )
+               lcr = uart_read ( uart, UART_LCR );
+       uart->lcr = lcr;
+       uart_write ( uart, UART_LCR, ( lcr | UART_LCR_DLAB ) );
+       if ( baud ) {
+               uart->divisor = ( UART_MAX_BAUD / baud );
+               dlm = ( ( uart->divisor >> 8 ) & 0xff );
+               dll = ( ( uart->divisor >> 0 ) & 0xff );
+               uart_write ( uart, UART_DLM, dlm );
+               uart_write ( uart, UART_DLL, dll );
+       } else {
+               dlm = uart_read ( uart, UART_DLM );
+               dll = uart_read ( uart, UART_DLL );
+               uart->divisor = ( ( dlm << 8 ) | dll );
+       }
+       uart_write ( uart, UART_LCR, ( lcr & ~UART_LCR_DLAB ) );
+
+       /* Disable interrupts */
+       uart_write ( uart, UART_IER, 0 );
+
+       /* Enable FIFOs */
+       uart_write ( uart, UART_FCR, UART_FCR_FE );
+
+       /* Assert DTR and RTS */
+       uart_write ( uart, UART_MCR, ( UART_MCR_DTR | UART_MCR_RTS ) );
+
+       /* Flush any stale data */
+       uart_flush ( uart );
+
+       return 0;
+}