ARM: footbridge: use GENERIC_IRQ_MULTI_HANDLER

Footbridge still uses the classic IRQ entry path in assembler,
but this is easily converted into an equivalent C version.

In this case, the correlation between IRQ numbers and bits in
the status register is non-obvious, and the priorities are
handled by manually checking each bit in a static order,
re-reading the status register after each handled event.

I moved the code into the new file and edited the syntax without
changing this sequence to keep the behavior as close as possible
to what it traditionally did.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/Kconfig

@@ -362,6 +362,7 @@ config ARCH_FOOTBRIDGE
 	select FOOTBRIDGE
 	select NEED_MACH_IO_H if !MMU
 	select NEED_MACH_MEMORY_H
+	select GENERIC_IRQ_MULTI_HANDLER
 	help
 	  Support for systems based on the DC21285 companion chip
 	  ("FootBridge"), such as the Simtec CATS and the Rebel NetWinder.

arch/arm/mach-footbridge/common.c

@@ -27,6 +27,91 @@
 
 #include "common.h"
 
+#include <mach/hardware.h>
+#include <mach/irqs.h>
+#include <asm/hardware/dec21285.h>
+
+static int dc21285_get_irq(void)
+{
+	void __iomem *irqstatus = (void __iomem *)CSR_IRQ_STATUS;
+	u32 mask = readl(irqstatus);
+
+	if (mask & IRQ_MASK_SDRAMPARITY)
+		return IRQ_SDRAMPARITY;
+
+	if (mask & IRQ_MASK_UART_RX)
+		return IRQ_CONRX;
+
+	if (mask & IRQ_MASK_DMA1)
+		return IRQ_DMA1;
+
+	if (mask & IRQ_MASK_DMA2)
+		return IRQ_DMA2;
+
+	if (mask & IRQ_MASK_IN0)
+		return IRQ_IN0;
+
+	if (mask & IRQ_MASK_IN1)
+		return IRQ_IN1;
+
+	if (mask & IRQ_MASK_IN2)
+		return IRQ_IN2;
+
+	if (mask & IRQ_MASK_IN3)
+		return IRQ_IN3;
+
+	if (mask & IRQ_MASK_PCI)
+		return IRQ_PCI;
+
+	if (mask & IRQ_MASK_DOORBELLHOST)
+		return IRQ_DOORBELLHOST;
+
+	if (mask & IRQ_MASK_I2OINPOST)
+		return IRQ_I2OINPOST;
+
+	if (mask & IRQ_MASK_TIMER1)
+		return IRQ_TIMER1;
+
+	if (mask & IRQ_MASK_TIMER2)
+		return IRQ_TIMER2;
+
+	if (mask & IRQ_MASK_TIMER3)
+		return IRQ_TIMER3;
+
+	if (mask & IRQ_MASK_UART_TX)
+		return IRQ_CONTX;
+
+	if (mask & IRQ_MASK_PCI_ABORT)
+		return IRQ_PCI_ABORT;
+
+	if (mask & IRQ_MASK_PCI_SERR)
+		return IRQ_PCI_SERR;
+
+	if (mask & IRQ_MASK_DISCARD_TIMER)
+		return IRQ_DISCARD_TIMER;
+
+	if (mask & IRQ_MASK_PCI_DPERR)
+		return IRQ_PCI_DPERR;
+
+	if (mask & IRQ_MASK_PCI_PERR)
+		return IRQ_PCI_PERR;
+
+	return 0;
+}
+
+static void dc21285_handle_irq(struct pt_regs *regs)
+{
+	int irq;
+	do {
+		irq = dc21285_get_irq();
+		if (!irq)
+			break;
+
+		generic_handle_irq(irq);
+	} while (1);
+}
+
+
 unsigned int mem_fclk_21285 = 50000000;
 
 EXPORT_SYMBOL(mem_fclk_21285);
@@ -108,6 +193,8 @@ static void __init __fb_init_irq(void)
 
 void __init footbridge_init_irq(void)
 {
+	set_handle_irq(dc21285_handle_irq);
+
 	__fb_init_irq();
 
 	if (!footbridge_cfn_mode())

arch/arm/mach-footbridge/include/mach/entry-macro.S

-/*
- * arch/arm/mach-footbridge/include/mach/entry-macro.S
- *
- * Low-level IRQ helper macros for footbridge-based platforms
- *
- * 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 <mach/hardware.h>
-#include <mach/irqs.h>
-#include <asm/hardware/dec21285.h>
-
-		.equ	dc21285_high, ARMCSR_BASE & 0xff000000
-		.equ	dc21285_low, ARMCSR_BASE & 0x00ffffff
-
-		.macro  get_irqnr_preamble, base, tmp
-		mov	\base, #dc21285_high
-		.if	dc21285_low
-		orr	\base, \base, #dc21285_low
-		.endif
-		.endm
-
-		.macro	get_irqnr_and_base, irqnr, irqstat, base, tmp
-		ldr	\irqstat, [\base, #0x180]	@ get interrupts
-
-		mov	\irqnr, #IRQ_SDRAMPARITY
-		tst	\irqstat, #IRQ_MASK_SDRAMPARITY
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_UART_RX
-		movne	\irqnr, #IRQ_CONRX
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_DMA1
-		movne	\irqnr, #IRQ_DMA1
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_DMA2
-		movne	\irqnr, #IRQ_DMA2
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_IN0
-		movne	\irqnr, #IRQ_IN0
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_IN1
-		movne	\irqnr, #IRQ_IN1
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_IN2
-		movne	\irqnr, #IRQ_IN2
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_IN3
-		movne	\irqnr, #IRQ_IN3
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_PCI
-		movne	\irqnr, #IRQ_PCI
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_DOORBELLHOST
-		movne	\irqnr, #IRQ_DOORBELLHOST
-		bne     1001f
-
-		tst	\irqstat, #IRQ_MASK_I2OINPOST
-		movne	\irqnr, #IRQ_I2OINPOST
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_TIMER1
-		movne	\irqnr, #IRQ_TIMER1
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_TIMER2
-		movne	\irqnr, #IRQ_TIMER2
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_TIMER3
-		movne	\irqnr, #IRQ_TIMER3
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_UART_TX
-		movne	\irqnr, #IRQ_CONTX
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_PCI_ABORT
-		movne	\irqnr, #IRQ_PCI_ABORT
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_PCI_SERR
-		movne	\irqnr, #IRQ_PCI_SERR
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_DISCARD_TIMER
-		movne	\irqnr, #IRQ_DISCARD_TIMER
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_PCI_DPERR
-		movne	\irqnr, #IRQ_PCI_DPERR
-		bne	1001f
-
-		tst	\irqstat, #IRQ_MASK_PCI_PERR
-		movne	\irqnr, #IRQ_PCI_PERR
-1001:
-		.endm
-