drivers/gfx/nvidia: Add driver for NVIDIA Optimus

Add a driver for systems with NVIDIA Optimus (hybrid) graphics using
GC6 3.0. The driver provides ACPI support for dynamically powering on
and off the GPU, and a function for enabling the GPU power in romstage.

Tested on system76/gaze15.

Change-Id: I2dec7aa2c8db7994f78a7cc1220502676e248465
Signed-off-by: Jeremy Soller <jeremy@system76.com>
Signed-off-by: Tim Crawford <tcrawford@system76.com>

src/drivers/gfx/nvidia/Kconfig

@@ -0,0 +1,10 @@
+config DRIVERS_GFX_NVIDIA
+	bool
+	default n
+	help
+	  Support for NVIDIA Optimus with GC6 3.0
+
+config DRIVERS_GFX_NVIDIA_BRIDGE
+	hex "PCI bridge for the GPU device"
+	default 0x01
+	depends on DRIVERS_GFX_NVIDIA

src/drivers/gfx/nvidia/Makefile.inc

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+romstage-$(CONFIG_DRIVERS_GFX_NVIDIA) += romstage.c
+
+ramstage-$(CONFIG_DRIVERS_GFX_NVIDIA) += nvidia.c

src/drivers/gfx/nvidia/acpi/gpu.asl

@@ -0,0 +1,202 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+Device (\_SB.PCI0.PEGP) {
+	Name (_ADR, CONFIG_DRIVERS_GFX_NVIDIA_BRIDGE << 16)
+
+	PowerResource (PWRR, 0, 0) {
+		Name (_STA, 1)
+
+		Method (_ON) {
+			Debug = "PEGP.PWRR._ON"
+			If (_STA != 1) {
+				\_SB.PCI0.PEGP.DEV0._ON ()
+				_STA = 1
+			}
+		}
+
+		Method (_OFF) {
+			Debug = "PEGP.PWRR._OFF"
+			If (_STA != 0) {
+				\_SB.PCI0.PEGP.DEV0._OFF ()
+				_STA = 0
+			}
+		}
+	}
+
+	Name (_PR0, Package () { \_SB.PCI0.PEGP.PWRR })
+	Name (_PR2, Package () { \_SB.PCI0.PEGP.PWRR })
+	Name (_PR3, Package () { \_SB.PCI0.PEGP.PWRR })
+}
+
+Device (\_SB.PCI0.PEGP.DEV0) {
+	Name(_ADR, 0x00000000)
+	Name (_STA, 0xF)
+	Name (LTRE, 0)
+
+	// Memory mapped PCI express registers
+	// Not sure what this stuff is, but it is used to get into GC6
+        // TODO: use GPU config to generate address
+	OperationRegion (RPCX, SystemMemory, CONFIG_MMCONF_BASE_ADDRESS + 0x8000, 0x1000)
+	Field (RPCX, ByteAcc, NoLock, Preserve) {
+		PVID,   16,
+		PDID,   16,
+		CMDR,   8,
+		Offset (0x19),
+		PRBN,   8,
+		Offset (0x84),
+		D0ST,   2,
+		Offset (0xAA),
+		CEDR,   1,
+		Offset (0xAC),
+			,   4,
+		CMLW,   6,
+		Offset (0xB0),
+		ASPM,   2,
+			,   2,
+		P0LD,   1,
+		RTLK,   1,
+		Offset (0xC9),
+			,   2,
+		LREN,   1,
+		Offset (0x11A),
+			,   1,
+		VCNP,   1,
+		Offset (0x214),
+		Offset (0x216),
+		P0LS,   4,
+		Offset (0x248),
+			,   7,
+		Q0L2,   1,
+		Q0L0,   1,
+		Offset (0x504),
+		Offset (0x506),
+		PCFG,   2,
+		Offset (0x508),
+		TREN,   1,
+		Offset (0xC20),
+			,   4,
+		P0AP,   2,
+		Offset (0xC38),
+			,   3,
+		P0RM,   1,
+		Offset (0xC74),
+		P0LT,   4,
+		Offset (0xD0C),
+			,   20,
+		LREV,   1
+	}
+
+	Method (_ON) {
+		Debug = "PEGP.DEV0._ON"
+
+		If (_STA != 0xF) {
+			Debug = "  If DGPU_PWR_EN low"
+			If (! GTXS (DGPU_PWR_EN)) {
+				Debug = "    DGPU_PWR_EN high"
+				STXS (DGPU_PWR_EN)
+
+				Debug = "    Sleep 16"
+				Sleep (16)
+			}
+
+			Debug = "  DGPU_RST_N high"
+			STXS(DGPU_RST_N)
+
+			Debug = "  Sleep 10"
+			Sleep (10)
+
+			Debug = "  Q0L0 = 1"
+			Q0L0 = 1
+
+			Debug = "  Sleep 16"
+			Sleep (16)
+
+			Debug = "  While Q0L0"
+			Local0 = 0
+			While (Q0L0) {
+				If ((Local0 > 4)) {
+					Debug = "    While Q0L0 timeout"
+					Break
+				}
+
+				Sleep (16)
+				Local0++
+			}
+
+			Debug = "  P0RM = 0"
+			P0RM = 0
+
+			Debug = "  P0AP = 0"
+			P0AP = 0
+
+			Debug = Concatenate("  LREN = ", ToHexString(LTRE))
+			LREN = LTRE
+
+			Debug = "  CEDR = 1"
+			CEDR = 1
+
+			Debug = "  CMDR |= 7"
+			CMDR |= 7
+
+			Debug = "  _STA = 0xF"
+			_STA = 0xF
+		}
+	}
+
+	Method (_OFF) {
+		Debug = "PEGP.DEV0._OFF"
+
+		If (_STA != 0x5) {
+			Debug = Concatenate("  LTRE = ", ToHexString(LREN))
+			LTRE = LREN
+
+			Debug = "  Q0L2 = 1"
+			Q0L2 = 1
+
+			Debug = "  Sleep 16"
+			Sleep (16)
+
+			Debug = "  While Q0L2"
+			Local0 = Zero
+			While (Q0L2) {
+				If ((Local0 > 4)) {
+					Debug = "    While Q0L2 timeout"
+					Break
+				}
+
+				Sleep (16)
+				Local0++
+			}
+
+			Debug = "  P0RM = 1"
+			P0RM = 1
+
+			Debug = "  P0AP = 3"
+			P0AP = 3
+
+			Debug = "  Sleep 10"
+			Sleep (10)
+
+			Debug = "  DGPU_RST_N low"
+			CTXS(DGPU_RST_N)
+
+			Debug = "  While DGPU_GC6 low"
+			Local0 = Zero
+			While (! GRXS(DGPU_GC6)) {
+				If ((Local0 > 4)) {
+					Debug = "    While DGPU_GC6 low timeout"
+
+					Debug = "    DGPU_PWR_EN low"
+					CTXS (DGPU_PWR_EN)
+					Break
+				}
+
+				Sleep (16)
+				Local0++
+			}
+
+			Debug = "  _STA = 0x5"
+			_STA = 0x5
+		}
+	}
+}

src/drivers/gfx/nvidia/chip.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _DRIVERS_GFX_NVIDIA_CHIP_H_
+#define _DRIVERS_GFX_NVIDIA_CHIP_H_
+
+struct drivers_gfx_nvidia_config {
+	/* TODO: Set GPIOs in devicetree? */
+};
+
+#endif /* _DRIVERS_GFX_NVIDIA_CHIP_H_ */

src/drivers/gfx/nvidia/gpu.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _DRIVERS_GFX_NVIDIA_GPU_H_
+#define _DRIVERS_GFX_NVIDIA_GPU_H_
+
+#include <stdbool.h>
+
+struct nvidia_gpu_config {
+	/* GPIO for GPU_PWR_EN */
+	unsigned int power_gpio;
+	/* GPIO for GPU_RST# */
+	unsigned int reset_gpio;
+	/* Enable or disable GPU power */
+	bool enable;
+};
+
+void nvidia_set_power(const struct nvidia_gpu_config *config);
+
+#endif /* _DRIVERS_NVIDIA_GPU_H_ */

src/drivers/gfx/nvidia/nvidia.c

@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include "chip.h"
+#include <console/console.h>
+#include <device/device.h>
+#include <device/pci.h>
+
+#define NVIDIA_SUBSYSTEM_ID_OFFSET 0x40
+
+static void nvidia_read_resources(struct device *dev)
+{
+	printk(BIOS_DEBUG, "%s: %s\n", __func__, dev_path(dev));
+
+	pci_dev_read_resources(dev);
+
+	// Find all BARs on GPU, mark them above 4g if prefetchable
+	for (int bar = PCI_BASE_ADDRESS_0; bar <= PCI_BASE_ADDRESS_5; bar += 4) {
+		struct resource *res = probe_resource(dev, bar);
+
+		if (res) {
+			if (res->flags & IORESOURCE_PREFETCH) {
+				printk(BIOS_INFO, "  BAR at 0x%02x marked above 4g\n", bar);
+				res->flags |= IORESOURCE_ABOVE_4G;
+			} else {
+				printk(BIOS_DEBUG, "  BAR at 0x%02x not prefetch\n", bar);
+			}
+		} else {
+			printk(BIOS_DEBUG, "  BAR at 0x%02x not found\n", bar);
+		}
+	}
+}
+
+static void nvidia_set_subsystem(struct device *dev, unsigned int vendor, unsigned int device)
+{
+	pci_write_config32(dev, NVIDIA_SUBSYSTEM_ID_OFFSET,
+		((device & 0xffff) << 16) | (vendor & 0xffff));
+}
+
+static struct pci_operations nvidia_device_ops_pci = {
+	.set_subsystem = nvidia_set_subsystem,
+};
+
+static struct device_operations nvidia_device_ops = {
+	.read_resources   = nvidia_read_resources,
+	.set_resources    = pci_dev_set_resources,
+	.enable_resources = pci_dev_enable_resources,
+#if CONFIG(HAVE_ACPI_TABLES)
+	.write_acpi_tables = pci_rom_write_acpi_tables,
+	.acpi_fill_ssdt    = pci_rom_ssdt,
+#endif
+	.init             = pci_dev_init,
+	.ops_pci          = &nvidia_device_ops_pci,
+
+};
+
+static void nvidia_enable(struct device *dev)
+{
+	if (!dev->enabled || dev->path.type != DEVICE_PATH_PCI)
+		return;
+
+	dev->ops = &nvidia_device_ops;
+}
+
+struct chip_operations drivers_gfx_nvidia_ops = {
+	CHIP_NAME("NVIDIA Optimus graphics device")
+	.enable_dev = nvidia_enable
+};

src/drivers/gfx/nvidia/romstage.c

@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <console/console.h>
+#include <delay.h>
+#include <device/device.h>
+#include <device/pci.h>
+#include <gpio.h>
+#include "chip.h"
+#include "gpu.h"
+
+void nvidia_set_power(const struct nvidia_gpu_config *config)
+{
+	if (!config->power_gpio || !config->reset_gpio) {
+		printk(BIOS_ERR, "%s: GPU_PWR_EN and GPU_RST# must be set\n", __func__);
+		return;
+	}
+
+	printk(BIOS_DEBUG, "%s: GPU_PWR_EN = %d\n",
+		__func__, config->power_gpio);
+	printk(BIOS_DEBUG, "%s: GPU_RST# = %d\n",
+		__func__, config->reset_gpio);
+
+	gpio_set(config->reset_gpio, 0);
+	mdelay(4);
+
+	if (config->enable) {
+		gpio_set(config->power_gpio, 1);
+		mdelay(4);
+		gpio_set(config->reset_gpio, 1);
+	} else {
+		gpio_set(config->power_gpio, 0);
+	}
+
+	mdelay(4);
+}