drivers: Add Cadence UART driver
Add a driver for the Cadence UART which is found in Xilinx Zynq SOCs.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
diff --git a/drivers/cadence/uart/cdns_console.S b/drivers/cadence/uart/cdns_console.S
new file mode 100644
index 0000000..2c7960d
--- /dev/null
+++ b/drivers/cadence/uart/cdns_console.S
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <arch.h>
+#include <asm_macros.S>
+#include <cadence/cdns_uart.h>
+
+ .globl console_core_init
+ .globl console_core_putc
+ .globl console_core_getc
+
+ /* -----------------------------------------------
+ * int console_core_init(unsigned long base_addr,
+ * unsigned int uart_clk, unsigned int baud_rate)
+ * Function to initialize the console without a
+ * C Runtime to print debug information. This
+ * function will be accessed by console_init and
+ * crash reporting.
+ * We assume that the bootloader already set up
+ * the HW (baud, ...) and only enable the trans-
+ * mitter and receiver here.
+ * In: x0 - console base address
+ * w1 - Uart clock in Hz
+ * w2 - Baud rate
+ * Out: return 1 on success else 0 on error
+ * Clobber list : x1, x2, x3
+ * -----------------------------------------------
+ */
+func console_core_init
+ /* Check the input base address */
+ cbz x0, core_init_fail
+ /* Check baud rate and uart clock for sanity */
+ cbz w1, core_init_fail
+ cbz w2, core_init_fail
+
+ /* RX/TX enabled & reset */
+ mov w3, #(R_UART_CR_TX_EN | R_UART_CR_RX_EN | R_UART_CR_TXRST | R_UART_CR_RXRST)
+ str w3, [x0, #R_UART_CR]
+
+ mov w0, #1
+ ret
+core_init_fail:
+ mov w0, wzr
+ ret
+endfunc console_core_init
+
+ /* --------------------------------------------------------
+ * int console_core_putc(int c, unsigned long base_addr)
+ * Function to output a character over the console. It
+ * returns the character printed on success or -1 on error.
+ * In : w0 - character to be printed
+ * x1 - console base address
+ * Out : return -1 on error else return character.
+ * Clobber list : x2
+ * --------------------------------------------------------
+ */
+func console_core_putc
+ /* Check the input parameter */
+ cbz x1, putc_error
+ /* Prepend '\r' to '\n' */
+ cmp w0, #0xA
+ b.ne 2f
+1:
+ /* Check if the transmit FIFO is full */
+ ldr w2, [x1, #R_UART_SR]
+ tbnz w2, #UART_SR_INTR_TFUL_BIT, 1b
+ mov w2, #0xD
+ str w2, [x1, #R_UART_TX]
+2:
+ /* Check if the transmit FIFO is full */
+ ldr w2, [x1, #R_UART_SR]
+ tbnz w2, #UART_SR_INTR_TFUL_BIT, 2b
+ str w0, [x1, #R_UART_TX]
+ ret
+putc_error:
+ mov w0, #-1
+ ret
+endfunc console_core_putc
+
+ /* ---------------------------------------------
+ * int console_core_getc(unsigned long base_addr)
+ * Function to get a character from the console.
+ * It returns the character grabbed on success
+ * or -1 on error.
+ * In : x0 - console base address
+ * Clobber list : x0, x1
+ * ---------------------------------------------
+ */
+func console_core_getc
+ cbz x0, getc_error
+1:
+ /* Check if the receive FIFO is empty */
+ ldr w1, [x0, #R_UART_SR]
+ tbnz w1, #UART_SR_INTR_REMPTY_BIT, 1b
+ ldr w1, [x0, #R_UART_RX]
+ mov w0, w1
+ ret
+getc_error:
+ mov w0, #-1
+ ret
+endfunc console_core_getc
diff --git a/include/drivers/cadence/cdns_uart.h b/include/drivers/cadence/cdns_uart.h
new file mode 100644
index 0000000..bc1cc90
--- /dev/null
+++ b/include/drivers/cadence/cdns_uart.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __CADENCE_UART_H__
+#define __CADENCE_UART_H__
+
+/* This is very minimalistic and will only work in QEMU. */
+
+/* CADENCE Registers */
+#define R_UART_CR 0
+#define R_UART_CR_RXRST (1 << 0) /* RX logic reset */
+#define R_UART_CR_TXRST (1 << 1) /* TX logic reset */
+#define R_UART_CR_RX_EN (1 << 2) /* RX enabled */
+#define R_UART_CR_TX_EN (1 << 4) /* TX enabled */
+
+#define R_UART_SR 0x2C
+#define UART_SR_INTR_REMPTY_BIT 1
+#define UART_SR_INTR_TFUL_BIT 4
+
+#define R_UART_TX 0x30
+#define R_UART_RX 0x30
+
+#endif