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Diffstat (limited to 'arch/arm/mach-omap1/ams-delta-fiq.c')
-rw-r--r--arch/arm/mach-omap1/ams-delta-fiq.c227
1 files changed, 227 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/ams-delta-fiq.c b/arch/arm/mach-omap1/ams-delta-fiq.c
new file mode 100644
index 0000000000..1f5852be05
--- /dev/null
+++ b/arch/arm/mach-omap1/ams-delta-fiq.c
@@ -0,0 +1,227 @@
+// 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 <linux/soc/ti/omap1-io.h>
+
+#include "hardware.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 (!WARN_ON_ONCE(!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. Initialize 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);
+}