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linux/arch/arm/mach-omap1/ams-delta-fiq-handler.S
Janusz Krzysztofik 60c3bf3f12 OMAP1: Amstrad Delta: add FIQ handler for serial keyboardport interrupt processing 
This patch introduces a Fast Interrupt Request (FIQ) handler for Amstrad Delta
(E3) videophone. The handler's purpose is to process interrupts generated by a
GPIO line that a serial keyboard clock hangs off. It collects consecutive bits
into words, pushing them into a buffer, then requests a higher level interrupt
after one or more words are ready for further processing by a keyboard port
driver.

The handler also processes interrupts generated by two other GPIO lines, used
by other on-board supported devices, by simply requesting a higher level
interrupt, that in turn should invoke those device's specific irq handlers.

IRQ12 line, not used by OMAP1510 hardware (described as reserved), has been
choosen as a higher level interrupt source.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2010-05-05 11:11:10 -07:00

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/*
* linux/arch/arm/mach-omap1/ams-delta-fiq-handler.S
*
* Based on linux/arch/arm/lib/floppydma.S
* Renamed and modified to work with 2.6 kernel by Matt Callow
* Copyright (C) 1995, 1996 Russell King
* Copyright (C) 2004 Pete Trapps
* Copyright (C) 2006 Matt Callow
* Copyright (C) 2010 Janusz Krzysztofik
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <plat/io.h>
#include <plat/board-ams-delta.h>
#include <mach/ams-delta-fiq.h>
/*
* GPIO related definitions, copied from arch/arm/plat-omap/gpio.c.
* Unfortunately, those were not placed in a separate header file.
*/
#define OMAP1510_GPIO_BASE 0xFFFCE000
#define OMAP1510_GPIO_DATA_INPUT 0x00
#define OMAP1510_GPIO_DATA_OUTPUT 0x04
#define OMAP1510_GPIO_DIR_CONTROL 0x08
#define OMAP1510_GPIO_INT_CONTROL 0x0c
#define OMAP1510_GPIO_INT_MASK 0x10
#define OMAP1510_GPIO_INT_STATUS 0x14
#define OMAP1510_GPIO_PIN_CONTROL 0x18
/* GPIO register bitmasks */
#define KEYBRD_DATA_MASK (0x1 << AMS_DELTA_GPIO_PIN_KEYBRD_DATA)
#define KEYBRD_CLK_MASK (0x1 << AMS_DELTA_GPIO_PIN_KEYBRD_CLK)
#define MODEM_IRQ_MASK (0x1 << AMS_DELTA_GPIO_PIN_MODEM_IRQ)
#define HOOK_SWITCH_MASK (0x1 << AMS_DELTA_GPIO_PIN_HOOK_SWITCH)
#define OTHERS_MASK (MODEM_IRQ_MASK | HOOK_SWITCH_MASK)
/* IRQ handler register bitmasks */
#define DEFERRED_FIQ_MASK (0x1 << (INT_DEFERRED_FIQ % IH2_BASE))
#define GPIO_BANK1_MASK (0x1 << INT_GPIO_BANK1)
/* Driver buffer byte offsets */
#define BUF_MASK (FIQ_MASK * 4)
#define BUF_STATE (FIQ_STATE * 4)
#define BUF_KEYS_CNT (FIQ_KEYS_CNT * 4)
#define BUF_TAIL_OFFSET (FIQ_TAIL_OFFSET * 4)
#define BUF_HEAD_OFFSET (FIQ_HEAD_OFFSET * 4)
#define BUF_BUF_LEN (FIQ_BUF_LEN * 4)
#define BUF_KEY (FIQ_KEY * 4)
#define BUF_MISSED_KEYS (FIQ_MISSED_KEYS * 4)
#define BUF_BUFFER_START (FIQ_BUFFER_START * 4)
#define BUF_GPIO_INT_MASK (FIQ_GPIO_INT_MASK * 4)
#define BUF_KEYS_HICNT (FIQ_KEYS_HICNT * 4)
#define BUF_IRQ_PEND (FIQ_IRQ_PEND * 4)
#define BUF_SIR_CODE_L1 (FIQ_SIR_CODE_L1 * 4)
#define BUF_SIR_CODE_L2 (IRQ_SIR_CODE_L2 * 4)
#define BUF_CNT_INT_00 (FIQ_CNT_INT_00 * 4)
#define BUF_CNT_INT_KEY (FIQ_CNT_INT_KEY * 4)
#define BUF_CNT_INT_MDM (FIQ_CNT_INT_MDM * 4)
#define BUF_CNT_INT_03 (FIQ_CNT_INT_03 * 4)
#define BUF_CNT_INT_HSW (FIQ_CNT_INT_HSW * 4)
#define BUF_CNT_INT_05 (FIQ_CNT_INT_05 * 4)
#define BUF_CNT_INT_06 (FIQ_CNT_INT_06 * 4)
#define BUF_CNT_INT_07 (FIQ_CNT_INT_07 * 4)
#define BUF_CNT_INT_08 (FIQ_CNT_INT_08 * 4)
#define BUF_CNT_INT_09 (FIQ_CNT_INT_09 * 4)
#define BUF_CNT_INT_10 (FIQ_CNT_INT_10 * 4)
#define BUF_CNT_INT_11 (FIQ_CNT_INT_11 * 4)
#define BUF_CNT_INT_12 (FIQ_CNT_INT_12 * 4)
#define BUF_CNT_INT_13 (FIQ_CNT_INT_13 * 4)
#define BUF_CNT_INT_14 (FIQ_CNT_INT_14 * 4)
#define BUF_CNT_INT_15 (FIQ_CNT_INT_15 * 4)
#define BUF_CIRC_BUFF (FIQ_CIRC_BUFF * 4)
/*
* Register useage
* r8 - temporary
* r9 - the driver buffer
* r10 - temporary
* r11 - interrupts mask
* r12 - base pointers
* r13 - interrupts status
*/
.text
.global qwerty_fiqin_end
ENTRY(qwerty_fiqin_start)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ FIQ intrrupt handler
ldr r12, omap_ih1_base @ set pointer to level1 handler
ldr r11, [r12, #IRQ_MIR_REG_OFFSET] @ fetch interrupts mask
ldr r13, [r12, #IRQ_ITR_REG_OFFSET] @ fetch interrupts status
bics r13, r13, r11 @ clear masked - any left?
beq exit @ none - spurious FIQ? exit
ldr r10, [r12, #IRQ_SIR_FIQ_REG_OFFSET] @ get requested interrupt number
mov r8, #2 @ reset FIQ agreement
str r8, [r12, #IRQ_CONTROL_REG_OFFSET]
cmp r10, #INT_GPIO_BANK1 @ is it GPIO bank interrupt?
beq gpio @ yes - process it
mov r8, #1
orr r8, r11, r8, lsl r10 @ mask spurious interrupt
str r8, [r12, #IRQ_MIR_REG_OFFSET]
exit:
subs pc, lr, #4 @ return from FIQ
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@@@@@@@@@@@@@@@@@@@@@@@@@@
gpio: @ GPIO bank interrupt handler
ldr r12, omap1510_gpio_base @ set base pointer to GPIO bank
ldr r11, [r12, #OMAP1510_GPIO_INT_MASK] @ fetch GPIO interrupts mask
restart:
ldr r13, [r12, #OMAP1510_GPIO_INT_STATUS] @ fetch status bits
bics r13, r13, r11 @ clear masked - any left?
beq exit @ no - spurious interrupt? exit
orr r11, r11, r13 @ mask all requested interrupts
str r11, [r12, #OMAP1510_GPIO_INT_MASK]
ands r10, r13, #KEYBRD_CLK_MASK @ extract keyboard status - set?
beq hksw @ no - try next source
@@@@@@@@@@@@@@@@@@@@@@
@ Keyboard clock FIQ mode interrupt handler
@ r10 now contains KEYBRD_CLK_MASK, use it
str r10, [r12, #OMAP1510_GPIO_INT_STATUS] @ ack the interrupt
bic r11, r11, r10 @ unmask it
str r11, [r12, #OMAP1510_GPIO_INT_MASK]
@ Process keyboard data
ldr r8, [r12, #OMAP1510_GPIO_DATA_INPUT] @ fetch GPIO input
ldr r10, [r9, #BUF_STATE] @ fetch kbd interface state
cmp r10, #0 @ are we expecting start bit?
bne data @ no - go to data processing
ands r8, r8, #KEYBRD_DATA_MASK @ check start bit - detected?
beq hksw @ no - try next source
@ r8 contains KEYBRD_DATA_MASK, use it
str r8, [r9, #BUF_STATE] @ enter data processing state
@ r10 already contains 0, reuse it
str r10, [r9, #BUF_KEY] @ clear keycode
mov r10, #2 @ reset input bit mask
str r10, [r9, #BUF_MASK]
@ Mask other GPIO line interrupts till key done
str r11, [r9, #BUF_GPIO_INT_MASK] @ save mask for later restore
mvn r11, #KEYBRD_CLK_MASK @ prepare all except kbd mask
str r11, [r12, #OMAP1510_GPIO_INT_MASK] @ store into the mask register
b restart @ restart
data: ldr r10, [r9, #BUF_MASK] @ fetch current input bit mask
@ r8 still contains GPIO input bits
ands r8, r8, #KEYBRD_DATA_MASK @ is keyboard data line low?
ldreq r8, [r9, #BUF_KEY] @ yes - fetch collected so far,
orreq r8, r8, r10 @ set 1 at current mask position
streq r8, [r9, #BUF_KEY] @ and save back
mov r10, r10, lsl #1 @ shift mask left
bics r10, r10, #0x800 @ have we got all the bits?
strne r10, [r9, #BUF_MASK] @ not yet - store the mask
bne restart @ and restart
@ r10 already contains 0, reuse it
str r10, [r9, #BUF_STATE] @ reset state to start
@ Key done - restore interrupt mask
ldr r10, [r9, #BUF_GPIO_INT_MASK] @ fetch saved mask
and r11, r11, r10 @ unmask all saved as unmasked
str r11, [r12, #OMAP1510_GPIO_INT_MASK] @ restore into the mask register
@ Try appending the keycode to the circular buffer
ldr r10, [r9, #BUF_KEYS_CNT] @ get saved keystrokes count
ldr r8, [r9, #BUF_BUF_LEN] @ get buffer size
cmp r10, r8 @ is buffer full?
beq hksw @ yes - key lost, next source
add r10, r10, #1 @ incremet keystrokes counter
str r10, [r9, #BUF_KEYS_CNT]
ldr r10, [r9, #BUF_TAIL_OFFSET] @ get buffer tail offset
@ r8 already contains buffer size
cmp r10, r8 @ end of buffer?
moveq r10, #0 @ yes - rewind to buffer start
ldr r12, [r9, #BUF_BUFFER_START] @ get buffer start address
add r12, r12, r10, LSL #2 @ calculate buffer tail address
ldr r8, [r9, #BUF_KEY] @ get last keycode
str r8, [r12] @ append it to the buffer tail
add r10, r10, #1 @ increment buffer tail offset
str r10, [r9, #BUF_TAIL_OFFSET]
ldr r10, [r9, #BUF_CNT_INT_KEY] @ increment interrupts counter
add r10, r10, #1
str r10, [r9, #BUF_CNT_INT_KEY]
@@@@@@@@@@@@@@@@@@@@@@@@
hksw: @Is hook switch interrupt requested?
tst r13, #HOOK_SWITCH_MASK @ is hook switch status bit set?
beq mdm @ no - try next source
@@@@@@@@@@@@@@@@@@@@@@@@
@ Hook switch interrupt FIQ mode simple handler
@ Don't toggle active edge, the switch always bounces
@ Increment hook switch interrupt counter
ldr r10, [r9, #BUF_CNT_INT_HSW]
add r10, r10, #1
str r10, [r9, #BUF_CNT_INT_HSW]
@@@@@@@@@@@@@@@@@@@@@@@@
mdm: @Is it a modem interrupt?
tst r13, #MODEM_IRQ_MASK @ is modem status bit set?
beq irq @ no - check for next interrupt
@@@@@@@@@@@@@@@@@@@@@@@@
@ Modem FIQ mode interrupt handler stub
@ Increment modem interrupt counter
ldr r10, [r9, #BUF_CNT_INT_MDM]
add r10, r10, #1
str r10, [r9, #BUF_CNT_INT_MDM]
@@@@@@@@@@@@@@@@@@@@@@@@
irq: @ Place deferred_fiq interrupt request
ldr r12, deferred_fiq_ih_base @ set pointer to IRQ handler
mov r10, #DEFERRED_FIQ_MASK @ set deferred_fiq bit
str r10, [r12, #IRQ_ISR_REG_OFFSET] @ place it in the ISR register
ldr r12, omap1510_gpio_base @ set pointer back to GPIO bank
b restart @ check for next GPIO interrupt
@@@@@@@@@@@@@@@@@@@@@@@@@@@
/*
* Virtual addresses for IO
*/
omap_ih1_base:
.word OMAP1_IO_ADDRESS(OMAP_IH1_BASE)
deferred_fiq_ih_base:
.word OMAP1_IO_ADDRESS(DEFERRED_FIQ_IH_BASE)
omap1510_gpio_base:
.word OMAP1_IO_ADDRESS(OMAP1510_GPIO_BASE)
qwerty_fiqin_end:
/*
* Check the size of the FIQ,
* it cannot go beyond 0xffff0200, and is copied to 0xffff001c
*/
.if (qwerty_fiqin_end - qwerty_fiqin_start) > (0x200 - 0x1c)
.err
.endif
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