1 files changed, 225 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 000000000..4eea3e39e
--- /dev/null
+++ b/arch/arm/mach-omap1/ams-delta-fiq.c
@@ -0,0 +1,225 @@
+// 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 (!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);
+}