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// SPDX-License-Identifier: GPL-2.0-only
/*
* Amstrad E3 FIQ handling
*
* Copyright (C) 2009 Janusz Krzysztofik
* Copyright (c) 2006 Matt Callow
* Copyright (c) 2004 Amstrad Plc
* Copyright (C) 2001 RidgeRun, Inc.
*
* Parts of this code are taken from linux/arch/arm/mach-omap/irq.c
* in the MontaVista 2.4 kernel (and the Amstrad changes therein)
*/
#include <linux/gpio/consumer.h>
#include <linux/gpio/machine.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/platform_data/ams-delta-fiq.h>
#include <linux/platform_device.h>
#include <asm/fiq.h>
#include "ams-delta-fiq.h"
#include "board-ams-delta.h"
static struct fiq_handler fh = {
.name = "ams-delta-fiq"
};
/*
* This buffer is shared between FIQ and IRQ contexts.
* The FIQ and IRQ isrs can both read and write it.
* It is structured as a header section several 32bit slots,
* followed by the circular buffer where the FIQ isr stores
* keystrokes received from the qwerty keyboard. See
* <linux/platform_data/ams-delta-fiq.h> for details of offsets.
*/
static unsigned int fiq_buffer[1024];
static struct irq_chip *irq_chip;
static struct irq_data *irq_data[16];
static unsigned int irq_counter[16];
static const char *pin_name[16] __initconst = {
[AMS_DELTA_GPIO_PIN_KEYBRD_DATA] = "keybrd_data",
[AMS_DELTA_GPIO_PIN_KEYBRD_CLK] = "keybrd_clk",
};
static irqreturn_t deferred_fiq(int irq, void *dev_id)
{
struct irq_data *d;
int gpio, irq_num, fiq_count;
/*
* For each handled GPIO interrupt, keep calling its interrupt handler
* until the IRQ counter catches the FIQ incremented interrupt counter.
*/
for (gpio = AMS_DELTA_GPIO_PIN_KEYBRD_CLK;
gpio <= AMS_DELTA_GPIO_PIN_HOOK_SWITCH; gpio++) {
d = irq_data[gpio];
irq_num = d->irq;
fiq_count = fiq_buffer[FIQ_CNT_INT_00 + gpio];
if (irq_counter[gpio] < fiq_count &&
gpio != AMS_DELTA_GPIO_PIN_KEYBRD_CLK) {
/*
* handle_simple_irq() that OMAP GPIO edge
* interrupts default to since commit 80ac93c27441
* requires interrupt already acked and unmasked.
*/
if (irq_chip->irq_ack)
irq_chip->irq_ack(d);
if (irq_chip->irq_unmask)
irq_chip->irq_unmask(d);
}
for (; irq_counter[gpio] < fiq_count; irq_counter[gpio]++)
generic_handle_irq(irq_num);
}
return IRQ_HANDLED;
}
void __init ams_delta_init_fiq(struct gpio_chip *chip,
struct platform_device *serio)
{
struct gpio_desc *gpiod, *data = NULL, *clk = NULL;
void *fiqhandler_start;
unsigned int fiqhandler_length;
struct pt_regs FIQ_regs;
unsigned long val, offset;
int i, retval;
/* Store irq_chip location for IRQ handler use */
irq_chip = chip->irq.chip;
if (!irq_chip) {
pr_err("%s: GPIO chip %s is missing IRQ function\n", __func__,
chip->label);
return;
}
for (i = 0; i < ARRAY_SIZE(irq_data); i++) {
gpiod = gpiochip_request_own_desc(chip, i, pin_name[i],
GPIO_ACTIVE_HIGH, GPIOD_IN);
if (IS_ERR(gpiod)) {
pr_err("%s: failed to get GPIO pin %d (%ld)\n",
__func__, i, PTR_ERR(gpiod));
return;
}
/* Store irq_data location for IRQ handler use */
irq_data[i] = irq_get_irq_data(gpiod_to_irq(gpiod));
/*
* FIQ handler takes full control over serio data and clk GPIO
* pins. Initiaize them and keep requested so nobody can
* interfere. Fail if any of those two couldn't be requested.
*/
switch (i) {
case AMS_DELTA_GPIO_PIN_KEYBRD_DATA:
data = gpiod;
gpiod_direction_input(data);
break;
case AMS_DELTA_GPIO_PIN_KEYBRD_CLK:
clk = gpiod;
gpiod_direction_input(clk);
break;
default:
gpiochip_free_own_desc(gpiod);
break;
}
}
if (!data || !clk)
goto out_gpio;
fiqhandler_start = &qwerty_fiqin_start;
fiqhandler_length = &qwerty_fiqin_end - &qwerty_fiqin_start;
pr_info("Installing fiq handler from %p, length 0x%x\n",
fiqhandler_start, fiqhandler_length);
retval = claim_fiq(&fh);
if (retval) {
pr_err("ams_delta_init_fiq(): couldn't claim FIQ, ret=%d\n",
retval);
goto out_gpio;
}
retval = request_irq(INT_DEFERRED_FIQ, deferred_fiq,
IRQ_TYPE_EDGE_RISING, "deferred_fiq", NULL);
if (retval < 0) {
pr_err("Failed to get deferred_fiq IRQ, ret=%d\n", retval);
release_fiq(&fh);
goto out_gpio;
}
/*
* Since no set_type() method is provided by OMAP irq chip,
* switch to edge triggered interrupt type manually.
*/
offset = IRQ_ILR0_REG_OFFSET +
((INT_DEFERRED_FIQ - NR_IRQS_LEGACY) & 0x1f) * 0x4;
val = omap_readl(DEFERRED_FIQ_IH_BASE + offset) & ~(1 << 1);
omap_writel(val, DEFERRED_FIQ_IH_BASE + offset);
set_fiq_handler(fiqhandler_start, fiqhandler_length);
/*
* Initialise the buffer which is shared
* between FIQ mode and IRQ mode
*/
fiq_buffer[FIQ_GPIO_INT_MASK] = 0;
fiq_buffer[FIQ_MASK] = 0;
fiq_buffer[FIQ_STATE] = 0;
fiq_buffer[FIQ_KEY] = 0;
fiq_buffer[FIQ_KEYS_CNT] = 0;
fiq_buffer[FIQ_KEYS_HICNT] = 0;
fiq_buffer[FIQ_TAIL_OFFSET] = 0;
fiq_buffer[FIQ_HEAD_OFFSET] = 0;
fiq_buffer[FIQ_BUF_LEN] = 256;
fiq_buffer[FIQ_MISSED_KEYS] = 0;
fiq_buffer[FIQ_BUFFER_START] =
(unsigned int) &fiq_buffer[FIQ_CIRC_BUFF];
for (i = FIQ_CNT_INT_00; i <= FIQ_CNT_INT_15; i++)
fiq_buffer[i] = 0;
/*
* FIQ mode r9 always points to the fiq_buffer, because the FIQ isr
* will run in an unpredictable context. The fiq_buffer is the FIQ isr's
* only means of communication with the IRQ level and other kernel
* context code.
*/
FIQ_regs.ARM_r9 = (unsigned int)fiq_buffer;
set_fiq_regs(&FIQ_regs);
pr_info("request_fiq(): fiq_buffer = %p\n", fiq_buffer);
/*
* Redirect GPIO interrupts to FIQ
*/
offset = IRQ_ILR0_REG_OFFSET + (INT_GPIO_BANK1 - NR_IRQS_LEGACY) * 0x4;
val = omap_readl(OMAP_IH1_BASE + offset) | 1;
omap_writel(val, OMAP_IH1_BASE + offset);
/* Initialize serio device IRQ resource and platform_data */
serio->resource[0].start = gpiod_to_irq(clk);
serio->resource[0].end = serio->resource[0].start;
serio->dev.platform_data = fiq_buffer;
/*
* Since FIQ handler performs handling of GPIO registers for
* "keybrd_clk" IRQ pin, ams_delta_serio driver used to set
* handle_simple_irq() as active IRQ handler for that pin to avoid
* bad interaction with gpio-omap driver. This is no longer needed
* as handle_simple_irq() is now the default handler for OMAP GPIO
* edge interrupts.
* This comment replaces the obsolete code which has been removed
* from the ams_delta_serio driver and stands here only as a reminder
* of that dependency on gpio-omap driver behavior.
*/
return;
out_gpio:
if (data)
gpiochip_free_own_desc(data);
if (clk)
gpiochip_free_own_desc(clk);
}
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