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Diffstat (limited to 'arch/mips/momentum/ocelot_c/uart-irq.c')
-rw-r--r--arch/mips/momentum/ocelot_c/uart-irq.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/mips/momentum/ocelot_c/uart-irq.c b/arch/mips/momentum/ocelot_c/uart-irq.c
new file mode 100644
index 000000000000..ebe1507b17df
--- /dev/null
+++ b/arch/mips/momentum/ocelot_c/uart-irq.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright 2002 Momentum Computer
+ * Author: mdharm@momenco.com
+ *
+ * arch/mips/momentum/ocelot_c/uart-irq.c
+ * Interrupt routines for UARTs. Interrupt numbers are assigned from
+ * 80 to 81 (2 interrupt sources).
+ *
+ * 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 (at your
+ * option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <asm/ptrace.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include "ocelot_c_fpga.h"
+
+static inline int ls1bit8(unsigned int x)
+{
+ int b = 7, s;
+
+ s = 4; if (((unsigned char)(x << 4)) == 0) s = 0; b -= s; x <<= s;
+ s = 2; if (((unsigned char)(x << 2)) == 0) s = 0; b -= s; x <<= s;
+ s = 1; if (((unsigned char)(x << 1)) == 0) s = 0; b -= s;
+
+ return b;
+}
+
+/* mask off an interrupt -- 0 is enable, 1 is disable */
+static inline void mask_uart_irq(unsigned int irq)
+{
+ uint8_t value;
+
+ value = OCELOT_FPGA_READ(UART_INTMASK);
+ value |= 1 << (irq - 74);
+ OCELOT_FPGA_WRITE(value, UART_INTMASK);
+
+ /* read the value back to assure that it's really been written */
+ value = OCELOT_FPGA_READ(UART_INTMASK);
+}
+
+/* unmask an interrupt -- 0 is enable, 1 is disable */
+static inline void unmask_uart_irq(unsigned int irq)
+{
+ uint8_t value;
+
+ value = OCELOT_FPGA_READ(UART_INTMASK);
+ value &= ~(1 << (irq - 74));
+ OCELOT_FPGA_WRITE(value, UART_INTMASK);
+
+ /* read the value back to assure that it's really been written */
+ value = OCELOT_FPGA_READ(UART_INTMASK);
+}
+
+/*
+ * Enables the IRQ in the FPGA
+ */
+static void enable_uart_irq(unsigned int irq)
+{
+ unmask_uart_irq(irq);
+}
+
+/*
+ * Initialize the IRQ in the FPGA
+ */
+static unsigned int startup_uart_irq(unsigned int irq)
+{
+ unmask_uart_irq(irq);
+ return 0;
+}
+
+/*
+ * Disables the IRQ in the FPGA
+ */
+static void disable_uart_irq(unsigned int irq)
+{
+ mask_uart_irq(irq);
+}
+
+/*
+ * Masks and ACKs an IRQ
+ */
+static void mask_and_ack_uart_irq(unsigned int irq)
+{
+ mask_uart_irq(irq);
+}
+
+/*
+ * End IRQ processing
+ */
+static void end_uart_irq(unsigned int irq)
+{
+ if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
+ unmask_uart_irq(irq);
+}
+
+/*
+ * Interrupt handler for interrupts coming from the FPGA chip.
+ */
+void ll_uart_irq(struct pt_regs *regs)
+{
+ unsigned int irq_src, irq_mask;
+
+ /* read the interrupt status registers */
+ irq_src = OCELOT_FPGA_READ(UART_INTSTAT);
+ irq_mask = OCELOT_FPGA_READ(UART_INTMASK);
+
+ /* mask for just the interrupts we want */
+ irq_src &= ~irq_mask;
+
+ do_IRQ(ls1bit8(irq_src) + 74, regs);
+}
+
+#define shutdown_uart_irq disable_uart_irq
+
+struct hw_interrupt_type uart_irq_type = {
+ "UART/FPGA",
+ startup_uart_irq,
+ shutdown_uart_irq,
+ enable_uart_irq,
+ disable_uart_irq,
+ mask_and_ack_uart_irq,
+ end_uart_irq,
+ NULL
+};
+
+void uart_irq_init(void)
+{
+ /* Reset irq handlers pointers to NULL */
+ irq_desc[80].status = IRQ_DISABLED;
+ irq_desc[80].action = 0;
+ irq_desc[80].depth = 2;
+ irq_desc[80].handler = &uart_irq_type;
+
+ irq_desc[81].status = IRQ_DISABLED;
+ irq_desc[81].action = 0;
+ irq_desc[81].depth = 2;
+ irq_desc[81].handler = &uart_irq_type;
+}