drm: Add kms driver for loongson display controller

Loongson display controller IP has been integrated in both Loongson north
bridge chipset (ls7a1000/ls7a2000) and Loongson SoCs (ls2k1000/ls2k2000).
It has even been included in Loongson's BMC products. It has two display
pipes, and each display pipe supports a primary plane and a cursor plane.

For the DC in the LS7a1000, each display pipe has a DVO output interface,
which is able to support 1920x1080@60Hz. For the DC in the LS7A2000, each
display pipe is equipped with a built-in HDMI encoder, which is compliant
with the HDMI 1.4 specification. The first display pipe is also equipped
with a transparent VGA encoder, which is parallel with the HDMI encoder.
To get a decent performance for writing framebuffer data to the VRAM, the
write combine support should be enabled.

v1 -> v2:
 1) Use hpd status reg when polling for ls7a2000.
 2) Fix all warnings that emerged when compiling with W=1.

v2 -> v3:
 1) Add COMPILE_TEST to Kconfig and make the driver off by default
 2) Alphabetical sorting headers (Thomas)
 3) Untangle register access functions as much as possible (Thomas)
 4) Switch to TTM-based memory manager (Thomas)
 5) Add the chip ID detection function which can be used to distinguish
    chip models
 6) Revise the built-in HDMI phy driver, nearly all main stream mode below
    4K@30Hz is tested, and this driver supports clone(mirror) display mode
    and extend(joint) display mode.

v3 -> v4:
 1) Quickly fix a small mistake.

v4 -> v5:
 1) Add per display pipe debugfs support to the builtin HDMI encoder.

v5 -> v6:
 1) Remove stray code which didn't get used, say lsdc_of_get_reserved_ram
 2) Fix all typos I could found, make sentences and code more readable
 3) Untangle lsdc_hdmi*_connector_detect() function according to the pipe
 4) Rename this driver as loongson.

v6 -> v7:
1) Add prime support for buffer self-sharing, sharing buffer with
   drm/etnaviv is also tested and it works with limitations.
2) Implement buffer object tracking with list_head.
3) Add S3(sleep to RAM) support
4) Rewrite lsdc_bo_move since TTM core stop allocating resources
    during BO creation. Patch V1 ~ V6 of this series no longer work.
    Thus, we send V7.

v7 -> v8:
 1) Zero a compile warning on a 32-bit platform, compile with W=1
 2) Revise lsdc_bo_gpu_offset() and make minor cleanups.
 3) Pageflip tested on the virtual terminal with the following commands:

    modetest -M loongson -s 32:1920x1080 -v
    modetest -M loongson -s 34:1920x1080 -v -F tiles

   It works like a charm, when running the pageflip test with dual screens
   configuration, another two additional BOs were created by the modetest,
   VRAM usage up to 40+ MB, well we have at least 64MB, still enough.

   # cat bos

       bo[0000]: size:     8112kB VRAM
       bo[0001]: size:       16kB VRAM
       bo[0002]: size:       16kB VRAM
       bo[0003]: size:    16208kB VRAM
       bo[0004]: size:     8112kB VRAM
       bo[0005]: size:     8112kB VRAM

v8 -> v9:
 1) Select I2C and I2C_ALGOBIT in Kconfig, should depend on MMU.
 2) Using pci_get_domain_bus_and_slot to get the GPU device.

v9 -> v10:
 1) Revise lsdc_drm_freeze() to implement S3 correctly. We realized that
    the pinned BO could not be moved, the VRAM lost power when sleeping
    to RAM. Thus, the data in the buffer who is pinned in VRAM will get
    lost when resumed. Yet it's not a big problem because this driver
    relies on the CPU to update the front framebuffer. We can see the
    garbage data when resume from S3, but the screen will show the right
    image as I move the cursor. This is due to the CPU repaint. v10 of
    this patch makes S3 perfect by unpin all of the BOs in VRAM, evict
    them all to system RAM in lsdc_drm_freeze().

v10 -> v11:
 1) On a double-screen case, The buffer object backing the single giant
    framebuffer is referenced by two GEM objects; hence, it will be
    pinned at least twice by prepare_fb() function. This causes its pin
    count > 1. V10 of this patch only unpins VRAM BOs once when suspend,
    which is not correct on double-screen case. V11 of this patch unpin
    the BOs until its pin count reaches zero when suspend. Then, we make
    the S3 support complete finally. With v11, I can't see any garbage
    data when resume.

 2) Fix vblank wait timeout when disable CRTC.
 3) Test against IGT, at least fbdev test and kms_flip test passed.
 4) Rewrite pixel PLL update function, magic numbers eliminated (Emil)
 5) Drop a few common hardware features description in lsdc_desc (Emil)
 6) Drop lsdc_mode_config_mode_valid(), instead add restrictions in dumb
    create function. (Emil)
 7) Untangle the ls7a1000 case and ls7a2000 case completely (Thomas)

v11 -> v12:
 none

v12 -> v13:
 1) Add benchmarks to figure out the bandwidth of the hardware platform.
    Usage:
    # cd /sys/kernel/debug/dri/0/
    # cat benchmark

 2) VRAM is filled with garbage data if uninitialized, add a buffer
    clearing procedure (lsdc_bo_clear), clear the BO on creation time.
 3) Update copyrights and adjust coding style (Huacai)

v13 -> v14:
 1) Trying to add async update support for cursor plane.

v14 -> v15:
 1) Add lsdc_vga_set_decode() funciton, which allow us remove multi-video
    cards workaround, now it allow drm/loongson, drm/amdgpu, drm/etnaviv
    co-exist in the system, more is also possible (Emil and Xuerui)
 2) Fix typos and grammar mistakes as much as possible (Xuerui)
 3) Unify copyrights as GPL-2.0+ (Xuerui)
 4) Fix a bug introduce since V13, TTM may import BO from other drivers,
    we shouldn't clear it on such a case.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: loongson-kernel@lists.loongnix.cn
Tested-by: Liu Peibao <liupeibao@loongson.cn>
Tested-by: Li Yi  <liyi@loongson.cn>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20230615143613.1236245-2-15330273260@189.cn

1 files changed, 456 insertions, 0 deletions

diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c b/drivers/gpu/drm/loongson/lsdc_drv.c
new file mode 100644
index 000000000000..188ec82afcfb
--- /dev/null
+++ b/drivers/gpu/drm/loongson/lsdc_drv.c
@@ -0,0 +1,456 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/pci.h>
+#include <linux/vgaarb.h>
+
+#include <drm/drm_aperture.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fbdev_generic.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_ioctl.h>
+#include <drm/drm_modeset_helper.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_vblank.h>
+
+#include "loongson_module.h"
+#include "lsdc_drv.h"
+#include "lsdc_gem.h"
+#include "lsdc_ttm.h"
+
+#define DRIVER_AUTHOR               "Sui Jingfeng <suijingfeng@loongson.cn>"
+#define DRIVER_NAME                 "loongson"
+#define DRIVER_DESC                 "drm driver for loongson graphics"
+#define DRIVER_DATE                 "20220701"
+#define DRIVER_MAJOR                1
+#define DRIVER_MINOR                0
+#define DRIVER_PATCHLEVEL           0
+
+DEFINE_DRM_GEM_FOPS(lsdc_gem_fops);
+
+static const struct drm_driver lsdc_drm_driver = {
+	.driver_features = DRIVER_MODESET | DRIVER_RENDER | DRIVER_GEM | DRIVER_ATOMIC,
+	.fops = &lsdc_gem_fops,
+
+	.name = DRIVER_NAME,
+	.desc = DRIVER_DESC,
+	.date = DRIVER_DATE,
+	.major = DRIVER_MAJOR,
+	.minor = DRIVER_MINOR,
+	.patchlevel = DRIVER_PATCHLEVEL,
+
+	.debugfs_init = lsdc_debugfs_init,
+	.dumb_create = lsdc_dumb_create,
+	.dumb_map_offset = lsdc_dumb_map_offset,
+	.gem_prime_import_sg_table = lsdc_prime_import_sg_table,
+};
+
+static const struct drm_mode_config_funcs lsdc_mode_config_funcs = {
+	.fb_create = drm_gem_fb_create,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+/* Display related */
+
+static int lsdc_modeset_init(struct lsdc_device *ldev,
+			     unsigned int num_crtc,
+			     const struct lsdc_kms_funcs *funcs,
+			     bool has_vblank)
+{
+	struct drm_device *ddev = &ldev->base;
+	struct lsdc_display_pipe *dispipe;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < num_crtc; i++) {
+		dispipe = &ldev->dispipe[i];
+
+		/* We need an index before crtc is initialized */
+		dispipe->index = i;
+
+		ret = funcs->create_i2c(ddev, dispipe, i);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < num_crtc; i++) {
+		struct i2c_adapter *ddc = NULL;
+
+		dispipe = &ldev->dispipe[i];
+		if (dispipe->li2c)
+			ddc = &dispipe->li2c->adapter;
+
+		ret = funcs->output_init(ddev, dispipe, ddc, i);
+		if (ret)
+			return ret;
+
+		ldev->num_output++;
+	}
+
+	for (i = 0; i < num_crtc; i++) {
+		dispipe = &ldev->dispipe[i];
+
+		ret = funcs->primary_plane_init(ddev, &dispipe->primary.base, i);
+		if (ret)
+			return ret;
+
+		ret = funcs->cursor_plane_init(ddev, &dispipe->cursor.base, i);
+		if (ret)
+			return ret;
+
+		ret = funcs->crtc_init(ddev, &dispipe->crtc.base,
+				       &dispipe->primary.base,
+				       &dispipe->cursor.base,
+				       i, has_vblank);
+		if (ret)
+			return ret;
+	}
+
+	drm_info(ddev, "Total %u outputs\n", ldev->num_output);
+
+	return 0;
+}
+
+static const struct drm_mode_config_helper_funcs lsdc_mode_config_helper_funcs = {
+	.atomic_commit_tail = drm_atomic_helper_commit_tail,
+};
+
+static int lsdc_mode_config_init(struct drm_device *ddev,
+				 const struct lsdc_desc *descp)
+{
+	int ret;
+
+	ret = drmm_mode_config_init(ddev);
+	if (ret)
+		return ret;
+
+	ddev->mode_config.funcs = &lsdc_mode_config_funcs;
+	ddev->mode_config.min_width = 1;
+	ddev->mode_config.min_height = 1;
+	ddev->mode_config.max_width = descp->max_width * LSDC_NUM_CRTC;
+	ddev->mode_config.max_height = descp->max_height * LSDC_NUM_CRTC;
+	ddev->mode_config.preferred_depth = 24;
+	ddev->mode_config.prefer_shadow = 1;
+
+	ddev->mode_config.cursor_width = descp->hw_cursor_h;
+	ddev->mode_config.cursor_height = descp->hw_cursor_h;
+
+	ddev->mode_config.helper_private = &lsdc_mode_config_helper_funcs;
+
+	if (descp->has_vblank_counter)
+		ddev->max_vblank_count = 0xffffffff;
+
+	return ret;
+}
+
+/*
+ * The GPU and display controller in the LS7A1000/LS7A2000/LS2K2000 are
+ * separated PCIE devices. They are two devices, not one. Bar 2 of the GPU
+ * device contains the base address and size of the VRAM, both the GPU and
+ * the DC could access the on-board VRAM.
+ */
+static int lsdc_get_dedicated_vram(struct lsdc_device *ldev,
+				   struct pci_dev *pdev_dc,
+				   const struct lsdc_desc *descp)
+{
+	struct drm_device *ddev = &ldev->base;
+	struct pci_dev *pdev_gpu;
+	resource_size_t base, size;
+
+	/*
+	 * The GPU has 00:06.0 as its BDF, while the DC has 00:06.1
+	 * This is true for the LS7A1000, LS7A2000 and LS2K2000.
+	 */
+	pdev_gpu = pci_get_domain_bus_and_slot(pci_domain_nr(pdev_dc->bus),
+					       pdev_dc->bus->number,
+					       PCI_DEVFN(6, 0));
+	if (!pdev_gpu) {
+		drm_err(ddev, "No GPU device, then no VRAM\n");
+		return -ENODEV;
+	}
+
+	base = pci_resource_start(pdev_gpu, 2);
+	size = pci_resource_len(pdev_gpu, 2);
+
+	ldev->vram_base = base;
+	ldev->vram_size = size;
+	ldev->gpu = pdev_gpu;
+
+	drm_info(ddev, "Dedicated vram start: 0x%llx, size: %uMiB\n",
+		 (u64)base, (u32)(size >> 20));
+
+	return 0;
+}
+
+static struct lsdc_device *
+lsdc_create_device(struct pci_dev *pdev,
+		   const struct lsdc_desc *descp,
+		   const struct drm_driver *driver)
+{
+	struct lsdc_device *ldev;
+	struct drm_device *ddev;
+	int ret;
+
+	ldev = devm_drm_dev_alloc(&pdev->dev, driver, struct lsdc_device, base);
+	if (IS_ERR(ldev))
+		return ldev;
+
+	ldev->dc = pdev;
+	ldev->descp = descp;
+
+	ddev = &ldev->base;
+
+	loongson_gfxpll_create(ddev, &ldev->gfxpll);
+
+	ret = lsdc_get_dedicated_vram(ldev, pdev, descp);
+	if (ret) {
+		drm_err(ddev, "Init VRAM failed: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	ret = drm_aperture_remove_conflicting_framebuffers(ldev->vram_base,
+							   ldev->vram_size,
+							   driver);
+	if (ret) {
+		drm_err(ddev, "Remove firmware framebuffers failed: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	ret = lsdc_ttm_init(ldev);
+	if (ret) {
+		drm_err(ddev, "Memory manager init failed: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	lsdc_gem_init(ddev);
+
+	/* Bar 0 of the DC device contains the MMIO register's base address */
+	ldev->reg_base = pcim_iomap(pdev, 0, 0);
+	if (!ldev->reg_base)
+		return ERR_PTR(-ENODEV);
+
+	spin_lock_init(&ldev->reglock);
+
+	ret = lsdc_mode_config_init(ddev, descp);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = lsdc_modeset_init(ldev, descp->num_of_crtc, descp->funcs,
+				loongson_vblank);
+	if (ret)
+		return ERR_PTR(ret);
+
+	drm_mode_config_reset(ddev);
+
+	return ldev;
+}
+
+/* For multiple GPU driver instance co-exixt in the system */
+
+static unsigned int lsdc_vga_set_decode(struct pci_dev *pdev, bool state)
+{
+	return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
+}
+
+static int lsdc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	const struct lsdc_desc *descp;
+	struct drm_device *ddev;
+	struct lsdc_device *ldev;
+	int ret;
+
+	descp = lsdc_device_probe(pdev, ent->driver_data);
+	if (IS_ERR_OR_NULL(descp))
+		return -ENODEV;
+
+	pci_set_master(pdev);
+
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(40));
+	if (ret)
+		return ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	dev_info(&pdev->dev, "Found %s, revision: %u",
+		 to_loongson_gfx(descp)->model, pdev->revision);
+
+	ldev = lsdc_create_device(pdev, descp, &lsdc_drm_driver);
+	if (IS_ERR(ldev))
+		return PTR_ERR(ldev);
+
+	ddev = &ldev->base;
+
+	pci_set_drvdata(pdev, ddev);
+
+	vga_client_register(pdev, lsdc_vga_set_decode);
+
+	drm_kms_helper_poll_init(ddev);
+
+	if (loongson_vblank) {
+		ret = drm_vblank_init(ddev, descp->num_of_crtc);
+		if (ret)
+			return ret;
+
+		ret = devm_request_irq(&pdev->dev, pdev->irq,
+				       descp->funcs->irq_handler,
+				       IRQF_SHARED,
+				       dev_name(&pdev->dev), ddev);
+		if (ret) {
+			drm_err(ddev, "Failed to register interrupt: %d\n", ret);
+			return ret;
+		}
+
+		drm_info(ddev, "registered irq: %u\n", pdev->irq);
+	}
+
+	ret = drm_dev_register(ddev, 0);
+	if (ret)
+		return ret;
+
+	drm_fbdev_generic_setup(ddev, 32);
+
+	return 0;
+}
+
+static void lsdc_pci_remove(struct pci_dev *pdev)
+{
+	struct drm_device *ddev = pci_get_drvdata(pdev);
+
+	drm_dev_unregister(ddev);
+	drm_atomic_helper_shutdown(ddev);
+}
+
+static int lsdc_drm_freeze(struct drm_device *ddev)
+{
+	struct lsdc_device *ldev = to_lsdc(ddev);
+	struct lsdc_bo *lbo;
+	int ret;
+
+	/* unpin all of buffers in the VRAM */
+	mutex_lock(&ldev->gem.mutex);
+	list_for_each_entry(lbo, &ldev->gem.objects, list) {
+		struct ttm_buffer_object *tbo = &lbo->tbo;
+		struct ttm_resource *resource = tbo->resource;
+		unsigned int pin_count = tbo->pin_count;
+
+		drm_dbg(ddev, "bo[%p], size: %zuKiB, type: %s, pin count: %u\n",
+			lbo, lsdc_bo_size(lbo) >> 10,
+			lsdc_mem_type_to_str(resource->mem_type), pin_count);
+
+		if (!pin_count)
+			continue;
+
+		if (resource->mem_type == TTM_PL_VRAM) {
+			ret = lsdc_bo_reserve(lbo);
+			if (unlikely(ret)) {
+				drm_err(ddev, "bo reserve failed: %d\n", ret);
+				continue;
+			}
+
+			do {
+				lsdc_bo_unpin(lbo);
+				--pin_count;
+			} while (pin_count);
+
+			lsdc_bo_unreserve(lbo);
+		}
+	}
+	mutex_unlock(&ldev->gem.mutex);
+
+	lsdc_bo_evict_vram(ddev);
+
+	ret = drm_mode_config_helper_suspend(ddev);
+	if (unlikely(ret)) {
+		drm_err(ddev, "Freeze error: %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lsdc_drm_resume(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct drm_device *ddev = pci_get_drvdata(pdev);
+
+	return drm_mode_config_helper_resume(ddev);
+}
+
+static int lsdc_pm_freeze(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct drm_device *ddev = pci_get_drvdata(pdev);
+
+	return lsdc_drm_freeze(ddev);
+}
+
+static int lsdc_pm_thaw(struct device *dev)
+{
+	return lsdc_drm_resume(dev);
+}
+
+static int lsdc_pm_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	int error;
+
+	error = lsdc_pm_freeze(dev);
+	if (error)
+		return error;
+
+	pci_save_state(pdev);
+	/* Shut down the device */
+	pci_disable_device(pdev);
+	pci_set_power_state(pdev, PCI_D3hot);
+
+	return 0;
+}
+
+static int lsdc_pm_resume(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	pci_set_power_state(pdev, PCI_D0);
+
+	pci_restore_state(pdev);
+
+	if (pcim_enable_device(pdev))
+		return -EIO;
+
+	return lsdc_pm_thaw(dev);
+}
+
+static const struct dev_pm_ops lsdc_pm_ops = {
+	.suspend = lsdc_pm_suspend,
+	.resume = lsdc_pm_resume,
+	.freeze = lsdc_pm_freeze,
+	.thaw = lsdc_pm_thaw,
+	.poweroff = lsdc_pm_freeze,
+	.restore = lsdc_pm_resume,
+};
+
+static const struct pci_device_id lsdc_pciid_list[] = {
+	{PCI_VDEVICE(LOONGSON, 0x7a06), CHIP_LS7A1000},
+	{PCI_VDEVICE(LOONGSON, 0x7a36), CHIP_LS7A2000},
+	{ }
+};
+
+struct pci_driver lsdc_pci_driver = {
+	.name = DRIVER_NAME,
+	.id_table = lsdc_pciid_list,
+	.probe = lsdc_pci_probe,
+	.remove = lsdc_pci_remove,
+	.driver.pm = &lsdc_pm_ops,
+};
+
+MODULE_DEVICE_TABLE(pci, lsdc_pciid_list);
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");