x86: apl: Add ITSS driver

This driver models some sort of interrupt thingy but there are so many
abreviations that I cannot find out what it stands for. Possibly something
to do with interrupts.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/cpu/apollolake/Makefile

@@ -5,5 +5,6 @@
 obj-$(CONFIG_SPL_BUILD) += systemagent.o
 
 obj-y += hostbridge.o
+obj-y += itss.o
 obj-y += pmc.o
 obj-y += uart.o

arch/x86/cpu/apollolake/itss.c

@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Something to do with Interrupts, but I don't know what ITSS stands for
+ *
+ * Copyright (C) 2017 Intel Corporation.
+ * Copyright (C) 2017 Siemens AG
+ * Copyright 2019 Google LLC
+ *
+ * Taken from coreboot itss.c
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dt-structs.h>
+#include <irq.h>
+#include <p2sb.h>
+#include <spl.h>
+#include <asm/arch/itss.h>
+
+struct apl_itss_platdata {
+#if CONFIG_IS_ENABLED(OF_PLATDATA)
+	/* Put this first since driver model will copy the data here */
+	struct dtd_intel_apl_itss dtplat;
+#endif
+};
+
+/* struct pmc_route - Routing for PMC to GPIO */
+struct pmc_route {
+	u32 pmc;
+	u32 gpio;
+};
+
+struct apl_itss_priv {
+	struct pmc_route *route;
+	uint route_count;
+	u32 irq_snapshot[NUM_IPC_REGS];
+};
+
+static int apl_set_polarity(struct udevice *dev, uint irq, bool active_low)
+{
+	u32 mask;
+	uint reg;
+
+	if (irq > ITSS_MAX_IRQ)
+		return -EINVAL;
+
+	reg = PCR_ITSS_IPC0_CONF + sizeof(u32) * (irq / IRQS_PER_IPC);
+	mask = 1 << (irq % IRQS_PER_IPC);
+
+	pcr_clrsetbits32(dev, reg, mask, active_low ? mask : 0);
+
+	return 0;
+}
+
+#ifndef CONFIG_TPL_BUILD
+static int apl_snapshot_polarities(struct udevice *dev)
+{
+	struct apl_itss_priv *priv = dev_get_priv(dev);
+	const int start = GPIO_IRQ_START;
+	const int end = GPIO_IRQ_END;
+	int reg_start;
+	int reg_end;
+	int i;
+
+	reg_start = start / IRQS_PER_IPC;
+	reg_end = (end + IRQS_PER_IPC - 1) / IRQS_PER_IPC;
+
+	for (i = reg_start; i < reg_end; i++) {
+		uint reg = PCR_ITSS_IPC0_CONF + sizeof(u32) * i;
+
+		priv->irq_snapshot[i] = pcr_read32(dev, reg);
+	}
+
+	return 0;
+}
+
+static void show_polarities(struct udevice *dev, const char *msg)
+{
+	int i;
+
+	log_info("ITSS IRQ Polarities %s:\n", msg);
+	for (i = 0; i < NUM_IPC_REGS; i++) {
+		uint reg = PCR_ITSS_IPC0_CONF + sizeof(u32) * i;
+
+		log_info("IPC%d: 0x%08x\n", i, pcr_read32(dev, reg));
+	}
+}
+
+static int apl_restore_polarities(struct udevice *dev)
+{
+	struct apl_itss_priv *priv = dev_get_priv(dev);
+	const int start = GPIO_IRQ_START;
+	const int end = GPIO_IRQ_END;
+	int reg_start;
+	int reg_end;
+	int i;
+
+	show_polarities(dev, "Before");
+
+	reg_start = start / IRQS_PER_IPC;
+	reg_end = (end + IRQS_PER_IPC - 1) / IRQS_PER_IPC;
+
+	for (i = reg_start; i < reg_end; i++) {
+		u32 mask;
+		u16 reg;
+		int irq_start;
+		int irq_end;
+
+		irq_start = i * IRQS_PER_IPC;
+		irq_end = min(irq_start + IRQS_PER_IPC - 1, ITSS_MAX_IRQ);
+
+		if (start > irq_end)
+			continue;
+		if (end < irq_start)
+			break;
+
+		/* Track bits within the bounds of of the register */
+		irq_start = max(start, irq_start) % IRQS_PER_IPC;
+		irq_end = min(end, irq_end) % IRQS_PER_IPC;
+
+		/* Create bitmask of the inclusive range of start and end */
+		mask = (((1U << irq_end) - 1) | (1U << irq_end));
+		mask &= ~((1U << irq_start) - 1);
+
+		reg = PCR_ITSS_IPC0_CONF + sizeof(u32) * i;
+		pcr_clrsetbits32(dev, reg, mask, mask & priv->irq_snapshot[i]);
+	}
+
+	show_polarities(dev, "After");
+
+	return 0;
+}
+#endif
+
+static int apl_route_pmc_gpio_gpe(struct udevice *dev, uint pmc_gpe_num)
+{
+	struct apl_itss_priv *priv = dev_get_priv(dev);
+	struct pmc_route *route;
+	int i;
+
+	for (i = 0, route = priv->route; i < priv->route_count; i++, route++) {
+		if (pmc_gpe_num == route->pmc)
+			return route->gpio;
+	}
+
+	return -ENOENT;
+}
+
+static int apl_itss_ofdata_to_platdata(struct udevice *dev)
+{
+	struct apl_itss_priv *priv = dev_get_priv(dev);
+	int ret;
+
+#if CONFIG_IS_ENABLED(OF_PLATDATA)
+	struct apl_itss_platdata *plat = dev_get_platdata(dev);
+	struct dtd_intel_apl_itss *dtplat = &plat->dtplat;
+
+	/*
+	 * It would be nice to do this in the bind() method, but with
+	 * of-platdata binding happens in the order that DM finds things in the
+	 * linker list (i.e. alphabetical order by driver name). So the GPIO
+	 * device may well be bound before its parent (p2sb), and this call
+	 * will fail if p2sb is not bound yet.
+	 *
+	 * TODO(sjg@chromium.org): Add a parent pointer to child devices in dtoc
+	 */
+	ret = p2sb_set_port_id(dev, dtplat->intel_p2sb_port_id);
+	if (ret)
+		return log_msg_ret("Could not set port id", ret);
+	priv->route = (struct pmc_route *)dtplat->intel_pmc_routes;
+	priv->route_count = ARRAY_SIZE(dtplat->intel_pmc_routes) /
+		 sizeof(struct pmc_route);
+#else
+	int size;
+
+	size = dev_read_size(dev, "intel,pmc-routes");
+	if (size < 0)
+		return size;
+	priv->route = malloc(size);
+	if (!priv->route)
+		return -ENOMEM;
+	ret = dev_read_u32_array(dev, "intel,pmc-routes", (u32 *)priv->route,
+				 size / sizeof(fdt32_t));
+	if (ret)
+		return log_msg_ret("Cannot read pmc-routes", ret);
+	priv->route_count = size / sizeof(struct pmc_route);
+#endif
+
+	return 0;
+}
+
+static const struct irq_ops apl_itss_ops = {
+	.route_pmc_gpio_gpe	= apl_route_pmc_gpio_gpe,
+	.set_polarity	= apl_set_polarity,
+#ifndef CONFIG_TPL_BUILD
+	.snapshot_polarities = apl_snapshot_polarities,
+	.restore_polarities = apl_restore_polarities,
+#endif
+};
+
+static const struct udevice_id apl_itss_ids[] = {
+	{ .compatible = "intel,apl-itss"},
+	{ }
+};
+
+U_BOOT_DRIVER(apl_itss_drv) = {
+	.name		= "intel_apl_itss",
+	.id		= UCLASS_IRQ,
+	.of_match	= apl_itss_ids,
+	.ops		= &apl_itss_ops,
+	.ofdata_to_platdata = apl_itss_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct apl_itss_platdata),
+	.priv_auto_alloc_size = sizeof(struct apl_itss_priv),
+};

arch/x86/include/asm/arch-apollolake/itss.h

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2017 Intel Corporation.
+ * Copyright 2019 Google LLC
+ *
+ * Modified from coreboot itss.h
+ */
+
+#ifndef _ASM_ARCH_ITSS_H
+#define _ASM_ARCH_ITSS_H
+
+#define GPIO_IRQ_START	50
+#define GPIO_IRQ_END	ITSS_MAX_IRQ
+
+#define ITSS_MAX_IRQ	119
+#define IRQS_PER_IPC	32
+#define NUM_IPC_REGS	((ITSS_MAX_IRQ + IRQS_PER_IPC - 1) / IRQS_PER_IPC)
+
+/* Max PXRC registers in ITSS */
+#define MAX_PXRC_CONFIG	(PCR_ITSS_PIRQH_ROUT - PCR_ITSS_PIRQA_ROUT + 1)
+
+/* PIRQA Routing Control Register */
+#define PCR_ITSS_PIRQA_ROUT	0x3100
+/* PIRQB Routing Control Register */
+#define PCR_ITSS_PIRQB_ROUT	0x3101
+/* PIRQC Routing Control Register */
+#define PCR_ITSS_PIRQC_ROUT	0x3102
+/* PIRQD Routing Control Register */
+#define PCR_ITSS_PIRQD_ROUT	0x3103
+/* PIRQE Routing Control Register */
+#define PCR_ITSS_PIRQE_ROUT	0x3104
+/* PIRQF Routing Control Register */
+#define PCR_ITSS_PIRQF_ROUT	0x3105
+/* PIRQG Routing Control Register */
+#define PCR_ITSS_PIRQG_ROUT	0x3106
+/* PIRQH Routing Control Register */
+#define PCR_ITSS_PIRQH_ROUT	0x3107
+/* ITSS Interrupt polarity control */
+#define PCR_ITSS_IPC0_CONF	0x3200
+/* ITSS Power reduction control */
+#define PCR_ITSS_ITSSPRC	0x3300
+
+#endif /* _ASM_ARCH_ITSS_H */