summaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/embedded6xx/ls_uart.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/platforms/embedded6xx/ls_uart.c')
-rw-r--r--arch/powerpc/platforms/embedded6xx/ls_uart.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/embedded6xx/ls_uart.c b/arch/powerpc/platforms/embedded6xx/ls_uart.c
new file mode 100644
index 000000000..9d891bd5d
--- /dev/null
+++ b/arch/powerpc/platforms/embedded6xx/ls_uart.c
@@ -0,0 +1,142 @@
+/*
+ * AVR power-management chip interface for the Buffalo Linkstation /
+ * Kurobox Platform.
+ *
+ * Author: 2006 (c) G. Liakhovetski
+ * g.liakhovetski@gmx.de
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of
+ * any kind, whether express or implied.
+ */
+#include <linux/workqueue.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/serial_reg.h>
+#include <linux/serial_8250.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/termbits.h>
+
+#include "mpc10x.h"
+
+static void __iomem *avr_addr;
+static unsigned long avr_clock;
+
+static struct work_struct wd_work;
+
+static void wd_stop(struct work_struct *unused)
+{
+ const char string[] = "AAAAFFFFJJJJ>>>>VVVV>>>>ZZZZVVVVKKKK";
+ int i = 0, rescue = 8;
+ int len = strlen(string);
+
+ while (rescue--) {
+ int j;
+ char lsr = in_8(avr_addr + UART_LSR);
+
+ if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) {
+ for (j = 0; j < 16 && i < len; j++, i++)
+ out_8(avr_addr + UART_TX, string[i]);
+ if (i == len) {
+ /* Read "OK" back: 4ms for the last "KKKK"
+ plus a couple bytes back */
+ msleep(7);
+ printk("linkstation: disarming the AVR watchdog: ");
+ while (in_8(avr_addr + UART_LSR) & UART_LSR_DR)
+ printk("%c", in_8(avr_addr + UART_RX));
+ break;
+ }
+ }
+ msleep(17);
+ }
+ printk("\n");
+}
+
+#define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600)
+
+void avr_uart_configure(void)
+{
+ unsigned char cval = UART_LCR_WLEN8;
+ unsigned int quot = AVR_QUOT(avr_clock);
+
+ if (!avr_addr || !avr_clock)
+ return;
+
+ out_8(avr_addr + UART_LCR, cval); /* initialise UART */
+ out_8(avr_addr + UART_MCR, 0);
+ out_8(avr_addr + UART_IER, 0);
+
+ cval |= UART_LCR_STOP | UART_LCR_PARITY | UART_LCR_EPAR;
+
+ out_8(avr_addr + UART_LCR, cval); /* Set character format */
+
+ out_8(avr_addr + UART_LCR, cval | UART_LCR_DLAB); /* set DLAB */
+ out_8(avr_addr + UART_DLL, quot & 0xff); /* LS of divisor */
+ out_8(avr_addr + UART_DLM, quot >> 8); /* MS of divisor */
+ out_8(avr_addr + UART_LCR, cval); /* reset DLAB */
+ out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO); /* enable FIFO */
+}
+
+void avr_uart_send(const char c)
+{
+ if (!avr_addr || !avr_clock)
+ return;
+
+ out_8(avr_addr + UART_TX, c);
+ out_8(avr_addr + UART_TX, c);
+ out_8(avr_addr + UART_TX, c);
+ out_8(avr_addr + UART_TX, c);
+}
+
+static void __init ls_uart_init(void)
+{
+ local_irq_disable();
+
+#ifndef CONFIG_SERIAL_8250
+ out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO); /* enable FIFO */
+ out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO |
+ UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); /* clear FIFOs */
+ out_8(avr_addr + UART_FCR, 0);
+ out_8(avr_addr + UART_IER, 0);
+
+ /* Clear up interrupts */
+ (void) in_8(avr_addr + UART_LSR);
+ (void) in_8(avr_addr + UART_RX);
+ (void) in_8(avr_addr + UART_IIR);
+ (void) in_8(avr_addr + UART_MSR);
+#endif
+ avr_uart_configure();
+
+ local_irq_enable();
+}
+
+static int __init ls_uarts_init(void)
+{
+ struct device_node *avr;
+ phys_addr_t phys_addr;
+ int len;
+
+ avr = of_find_node_by_path("/soc10x/serial@80004500");
+ if (!avr)
+ return -EINVAL;
+
+ avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
+ phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0];
+
+ if (!avr_clock || !phys_addr)
+ return -EINVAL;
+
+ avr_addr = ioremap(phys_addr, 32);
+ if (!avr_addr)
+ return -EFAULT;
+
+ ls_uart_init();
+
+ INIT_WORK(&wd_work, wd_stop);
+ schedule_work(&wd_work);
+
+ return 0;
+}
+
+machine_late_initcall(linkstation, ls_uarts_init);