[PATCH v7 04/17] x86: apl: Add hostbridge driver

[Simon Glass]

This driver models the hostbridge as a northbridge. It simply sets up the
graphics BAR. It supports of-platdata.

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

Changes in v7: None
Changes in v6:
- Fix comments for struct apl_hostbridge_platdata

Changes in v5: None
Changes in v4:
- Avoid needing to know internals of pinctrl in this driver
- Move code to pinctrl driver
- Switch over to use pinctrl for pad init/config

Changes in v3:
- Move pad programming into the hostbridge to reduce TPL device-tree size
- Use pci_get_devfn()

Changes in v2: None

 arch/x86/cpu/apollolake/Makefile     |   1 +
 arch/x86/cpu/apollolake/hostbridge.c | 179 +++++++++++++++++++++++++++
 2 files changed, 180 insertions(+)
 create mode 100644 arch/x86/cpu/apollolake/hostbridge.c

diff --git a/arch/x86/cpu/apollolake/Makefile b/arch/x86/cpu/apollolake/Makefile
index 3a8c2f66a3..4d3c08f84e 100644
--- a/arch/x86/cpu/apollolake/Makefile
+++ b/arch/x86/cpu/apollolake/Makefile
@@ -4,5 +4,6 @@
 
 obj-$(CONFIG_SPL_BUILD) += systemagent.o
 
+obj-y += hostbridge.o
 obj-y += pmc.o
 obj-y += uart.o
diff --git a/arch/x86/cpu/apollolake/hostbridge.c b/arch/x86/cpu/apollolake/hostbridge.c
new file mode 100644
index 0000000000..793853d5b5
--- /dev/null
+++ b/arch/x86/cpu/apollolake/hostbridge.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dt-structs.h>
+#include <spl.h>
+#include <asm/intel_pinctrl.h>
+#include <asm/intel_regs.h>
+#include <asm/pci.h>
+#include <asm/arch/systemagent.h>
+
+/**
+ * struct apl_hostbridge_platdata - platform data for hostbridge
+ *
+ * @dtplat: Platform data for of-platdata
+ * @early_pads: Early pad data to set up, each (pad, cfg0, cfg1)
+ * @early_pads_count: Number of pads to process
+ * @pciex_region_size: BAR length in bytes
+ * @bdf: Bus/device/function of hostbridge
+ */
+struct apl_hostbridge_platdata {
+#if CONFIG_IS_ENABLED(OF_PLATDATA)
+	struct dtd_intel_apl_hostbridge dtplat;
+#endif
+	u32 *early_pads;
+	int early_pads_count;
+	uint pciex_region_size;
+	pci_dev_t bdf;
+};
+
+enum {
+	PCIEXBAR		= 0x60,
+	PCIEXBAR_LENGTH_256MB	= 0,
+	PCIEXBAR_LENGTH_128MB,
+	PCIEXBAR_LENGTH_64MB,
+
+	PCIEXBAR_PCIEXBAREN	= 1 << 0,
+
+	TSEG			= 0xb8,  /* TSEG base */
+};
+
+static int apl_hostbridge_early_init_pinctrl(struct udevice *dev)
+{
+	struct apl_hostbridge_platdata *plat = dev_get_platdata(dev);
+	struct udevice *pinctrl;
+	int ret;
+
+	ret = uclass_first_device_err(UCLASS_PINCTRL, &pinctrl);
+	if (ret)
+		return log_msg_ret("no hostbridge pinctrl", ret);
+
+	return pinctrl_config_pads(pinctrl, plat->early_pads,
+				   plat->early_pads_count);
+}
+
+static int apl_hostbridge_early_init(struct udevice *dev)
+{
+	struct apl_hostbridge_platdata *plat = dev_get_platdata(dev);
+	u32 region_size;
+	ulong base;
+	u32 reg;
+	int ret;
+
+	/* Set up the MCHBAR */
+	pci_x86_read_config(plat->bdf, MCHBAR, &base, PCI_SIZE_32);
+	base = MCH_BASE_ADDRESS;
+	pci_x86_write_config(plat->bdf, MCHBAR, base | 1, PCI_SIZE_32);
+
+	/*
+	 * The PCIEXBAR is assumed to live in the memory mapped IO space under
+	 * 4GiB
+	 */
+	pci_x86_write_config(plat->bdf, PCIEXBAR + 4, 0, PCI_SIZE_32);
+
+	switch (plat->pciex_region_size >> 20) {
+	default:
+	case 256:
+		region_size = PCIEXBAR_LENGTH_256MB;
+		break;
+	case 128:
+		region_size = PCIEXBAR_LENGTH_128MB;
+		break;
+	case 64:
+		region_size = PCIEXBAR_LENGTH_64MB;
+		break;
+	}
+
+	reg = CONFIG_MMCONF_BASE_ADDRESS | (region_size << 1)
+				| PCIEXBAR_PCIEXBAREN;
+	pci_x86_write_config(plat->bdf, PCIEXBAR, reg, PCI_SIZE_32);
+
+	/*
+	 * TSEG defines the base of SMM range. BIOS determines the base
+	 * of TSEG memory which must be at or below Graphics base of GTT
+	 * Stolen memory, hence its better to clear TSEG register early
+	 * to avoid power on default non-zero value (if any).
+	 */
+	pci_x86_write_config(plat->bdf, TSEG, 0, PCI_SIZE_32);
+
+	ret = apl_hostbridge_early_init_pinctrl(dev);
+	if (ret)
+		return log_msg_ret("pinctrl", ret);
+
+	return 0;
+}
+
+static int apl_hostbridge_ofdata_to_platdata(struct udevice *dev)
+{
+	struct apl_hostbridge_platdata *plat = dev_get_platdata(dev);
+	struct udevice *pinctrl;
+	int ret;
+
+	/*
+	 * The host bridge holds the early pad data needed to get through TPL.
+	 * This is a small amount of data, enough to fit in TPL, so we keep it
+	 * separate from the full pad data, stored in the fsp-s subnode. That
+	 * subnode is not present in TPL, to save space.
+	 */
+	ret = uclass_first_device_err(UCLASS_PINCTRL, &pinctrl);
+	if (ret)
+		return log_msg_ret("no hostbridge PINCTRL", ret);
+#if !CONFIG_IS_ENABLED(OF_PLATDATA)
+	int root;
+
+	/* Get length of PCI Express Region */
+	plat->pciex_region_size = dev_read_u32_default(dev, "pciex-region-size",
+						       256 << 20);
+
+	root = pci_get_devfn(dev);
+	if (root < 0)
+		return log_msg_ret("Cannot get host-bridge PCI address", root);
+	plat->bdf = root;
+
+	ret = pinctrl_read_pads(pinctrl, dev_ofnode(dev), "early-pads",
+				&plat->early_pads, &plat->early_pads_count);
+	if (ret)
+		return log_msg_ret("early-pads", ret);
+#else
+	struct dtd_intel_apl_hostbridge *dtplat = &plat->dtplat;
+	int size;
+
+	plat->pciex_region_size = dtplat->pciex_region_size;
+	plat->bdf = pci_ofplat_get_devfn(dtplat->reg[0]);
+
+	/* Assume that if everything is 0, it is empty */
+	plat->early_pads = dtplat->early_pads;
+	size = ARRAY_SIZE(dtplat->early_pads);
+	plat->early_pads_count = pinctrl_count_pads(pinctrl, plat->early_pads,
+						    size);
+
+#endif
+
+	return 0;
+}
+
+static int apl_hostbridge_probe(struct udevice *dev)
+{
+	if (spl_phase() == PHASE_TPL)
+		return apl_hostbridge_early_init(dev);
+
+	return 0;
+}
+
+static const struct udevice_id apl_hostbridge_ids[] = {
+	{ .compatible = "intel,apl-hostbridge" },
+	{ }
+};
+
+U_BOOT_DRIVER(apl_hostbridge_drv) = {
+	.name		= "intel_apl_hostbridge",
+	.id		= UCLASS_NORTHBRIDGE,
+	.of_match	= apl_hostbridge_ids,
+	.ofdata_to_platdata = apl_hostbridge_ofdata_to_platdata,
+	.probe		= apl_hostbridge_probe,
+	.platdata_auto_alloc_size = sizeof(struct apl_hostbridge_platdata),
+};
-- 
2.24.0.393.g34dc348eaf-goog