linux/drivers/gpu/drm/mxsfb/mxsfb_drv.c
Marek Vasut 05ecc67835 drm: mxsfb: Implement LCDIF scanout CRC32 support
The LCDIF controller as present in i.MX28/i.MX6SX/i.MX8M Mini/Nano has
CRC_STAT register, which contains CRC32 of the frame as it was clocked
out of the DPI interface of the LCDIF. This is most likely meant as a
functional safety feature.

Unfortunately, there is zero documentation on how the CRC32 is calculated,
there is no documentation of the polynomial, the init value, nor on which
data is the checksum applied.

By applying brute-force on 8 pixel / 2 line frame, which is the minimum
size LCDIF would work with, it turns out the polynomial is CRC32_POLY_LE
0xedb88320 , init value is 0xffffffff , the input data are bitrev32()
of the entire frame and the resulting CRC has to be also bitrev32()ed.

Doing this calculation in kernel for each frame is unrealistic due to the
CPU demand, so attach the CRC collected from hardware to a frame instead.
The DRM subsystem already has an interface for this purpose and the CRC
can be accessed e.g. via debugfs:
"
$ echo auto > /sys/kernel/debug/dri/1/crtc-0/crc/control
$ cat /sys/kernel/debug/dri/1/crtc-0/crc/data
0x0000408c 0xa4e5cdd8
0x0000408d 0x72f537b4
"
The per-frame CRC can be used by userspace e.g. during automated testing,
to verify that whatever buffer was sent to be scanned out was actually
scanned out of the LCDIF correctly.

Acked-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexander Stein <alexander.stein@ew.tq-group.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Robby Cai <robby.cai@nxp.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stefan Agner <stefan@agner.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429212313.305556-1-marex@denx.de
2022-05-05 01:03:49 +02:00

437 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 Marek Vasut <marex@denx.de>
*
* This code is based on drivers/video/fbdev/mxsfb.c :
* Copyright (C) 2010 Juergen Beisert, Pengutronix
* Copyright (C) 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright (C) 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*/
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_bridge.h>
#include <drm/drm_connector.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_mode_config.h>
#include <drm/drm_module.h>
#include <drm/drm_of.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>
#include "mxsfb_drv.h"
#include "mxsfb_regs.h"
enum mxsfb_devtype {
MXSFB_V3,
MXSFB_V4,
/*
* Starting at i.MX6 the hardware version register is gone, use the
* i.MX family number as the version.
*/
MXSFB_V6,
};
static const struct mxsfb_devdata mxsfb_devdata[] = {
[MXSFB_V3] = {
.transfer_count = LCDC_V3_TRANSFER_COUNT,
.cur_buf = LCDC_V3_CUR_BUF,
.next_buf = LCDC_V3_NEXT_BUF,
.hs_wdth_mask = 0xff,
.hs_wdth_shift = 24,
.has_overlay = false,
.has_ctrl2 = false,
.has_crc32 = false,
},
[MXSFB_V4] = {
.transfer_count = LCDC_V4_TRANSFER_COUNT,
.cur_buf = LCDC_V4_CUR_BUF,
.next_buf = LCDC_V4_NEXT_BUF,
.hs_wdth_mask = 0x3fff,
.hs_wdth_shift = 18,
.has_overlay = false,
.has_ctrl2 = true,
.has_crc32 = true,
},
[MXSFB_V6] = {
.transfer_count = LCDC_V4_TRANSFER_COUNT,
.cur_buf = LCDC_V4_CUR_BUF,
.next_buf = LCDC_V4_NEXT_BUF,
.hs_wdth_mask = 0x3fff,
.hs_wdth_shift = 18,
.has_overlay = true,
.has_ctrl2 = true,
.has_crc32 = true,
},
};
void mxsfb_enable_axi_clk(struct mxsfb_drm_private *mxsfb)
{
if (mxsfb->clk_axi)
clk_prepare_enable(mxsfb->clk_axi);
}
void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb)
{
if (mxsfb->clk_axi)
clk_disable_unprepare(mxsfb->clk_axi);
}
static struct drm_framebuffer *
mxsfb_fb_create(struct drm_device *dev, struct drm_file *file_priv,
const struct drm_mode_fb_cmd2 *mode_cmd)
{
const struct drm_format_info *info;
info = drm_get_format_info(dev, mode_cmd);
if (!info)
return ERR_PTR(-EINVAL);
if (mode_cmd->width * info->cpp[0] != mode_cmd->pitches[0]) {
dev_dbg(dev->dev, "Invalid pitch: fb width must match pitch\n");
return ERR_PTR(-EINVAL);
}
return drm_gem_fb_create(dev, file_priv, mode_cmd);
}
static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = {
.fb_create = mxsfb_fb_create,
.atomic_check = drm_atomic_helper_check,
.atomic_commit = drm_atomic_helper_commit,
};
static const struct drm_mode_config_helper_funcs mxsfb_mode_config_helpers = {
.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
};
static int mxsfb_attach_bridge(struct mxsfb_drm_private *mxsfb)
{
struct drm_device *drm = mxsfb->drm;
struct drm_connector_list_iter iter;
struct drm_panel *panel;
struct drm_bridge *bridge;
int ret;
ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel,
&bridge);
if (ret)
return ret;
if (panel) {
bridge = devm_drm_panel_bridge_add_typed(drm->dev, panel,
DRM_MODE_CONNECTOR_DPI);
if (IS_ERR(bridge))
return PTR_ERR(bridge);
}
if (!bridge)
return -ENODEV;
ret = drm_bridge_attach(&mxsfb->encoder, bridge, NULL, 0);
if (ret)
return dev_err_probe(drm->dev, ret, "Failed to attach bridge\n");
mxsfb->bridge = bridge;
/*
* Get hold of the connector. This is a bit of a hack, until the bridge
* API gives us bus flags and formats.
*/
drm_connector_list_iter_begin(drm, &iter);
mxsfb->connector = drm_connector_list_iter_next(&iter);
drm_connector_list_iter_end(&iter);
return 0;
}
static irqreturn_t mxsfb_irq_handler(int irq, void *data)
{
struct drm_device *drm = data;
struct mxsfb_drm_private *mxsfb = drm->dev_private;
u32 reg, crc;
u64 vbc;
reg = readl(mxsfb->base + LCDC_CTRL1);
if (reg & CTRL1_CUR_FRAME_DONE_IRQ) {
drm_crtc_handle_vblank(&mxsfb->crtc);
if (mxsfb->crc_active) {
crc = readl(mxsfb->base + LCDC_V4_CRC_STAT);
vbc = drm_crtc_accurate_vblank_count(&mxsfb->crtc);
drm_crtc_add_crc_entry(&mxsfb->crtc, true, vbc, &crc);
}
}
writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
return IRQ_HANDLED;
}
static void mxsfb_irq_disable(struct drm_device *drm)
{
struct mxsfb_drm_private *mxsfb = drm->dev_private;
mxsfb_enable_axi_clk(mxsfb);
/* Disable and clear VBLANK IRQ */
writel(CTRL1_CUR_FRAME_DONE_IRQ_EN, mxsfb->base + LCDC_CTRL1 + REG_CLR);
writel(CTRL1_CUR_FRAME_DONE_IRQ, mxsfb->base + LCDC_CTRL1 + REG_CLR);
mxsfb_disable_axi_clk(mxsfb);
}
static int mxsfb_irq_install(struct drm_device *dev, int irq)
{
if (irq == IRQ_NOTCONNECTED)
return -ENOTCONN;
mxsfb_irq_disable(dev);
return request_irq(irq, mxsfb_irq_handler, 0, dev->driver->name, dev);
}
static void mxsfb_irq_uninstall(struct drm_device *dev)
{
struct mxsfb_drm_private *mxsfb = dev->dev_private;
mxsfb_irq_disable(dev);
free_irq(mxsfb->irq, dev);
}
static int mxsfb_load(struct drm_device *drm,
const struct mxsfb_devdata *devdata)
{
struct platform_device *pdev = to_platform_device(drm->dev);
struct mxsfb_drm_private *mxsfb;
struct resource *res;
int ret;
mxsfb = devm_kzalloc(&pdev->dev, sizeof(*mxsfb), GFP_KERNEL);
if (!mxsfb)
return -ENOMEM;
mxsfb->drm = drm;
drm->dev_private = mxsfb;
mxsfb->devdata = devdata;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mxsfb->base = devm_ioremap_resource(drm->dev, res);
if (IS_ERR(mxsfb->base))
return PTR_ERR(mxsfb->base);
mxsfb->clk = devm_clk_get(drm->dev, NULL);
if (IS_ERR(mxsfb->clk))
return PTR_ERR(mxsfb->clk);
mxsfb->clk_axi = devm_clk_get(drm->dev, "axi");
if (IS_ERR(mxsfb->clk_axi))
mxsfb->clk_axi = NULL;
mxsfb->clk_disp_axi = devm_clk_get(drm->dev, "disp_axi");
if (IS_ERR(mxsfb->clk_disp_axi))
mxsfb->clk_disp_axi = NULL;
ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
if (ret)
return ret;
pm_runtime_enable(drm->dev);
/* Modeset init */
drm_mode_config_init(drm);
ret = mxsfb_kms_init(mxsfb);
if (ret < 0) {
dev_err(drm->dev, "Failed to initialize KMS pipeline\n");
goto err_vblank;
}
ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
if (ret < 0) {
dev_err(drm->dev, "Failed to initialise vblank\n");
goto err_vblank;
}
/* Start with vertical blanking interrupt reporting disabled. */
drm_crtc_vblank_off(&mxsfb->crtc);
ret = mxsfb_attach_bridge(mxsfb);
if (ret) {
dev_err_probe(drm->dev, ret, "Cannot connect bridge\n");
goto err_vblank;
}
drm->mode_config.min_width = MXSFB_MIN_XRES;
drm->mode_config.min_height = MXSFB_MIN_YRES;
drm->mode_config.max_width = MXSFB_MAX_XRES;
drm->mode_config.max_height = MXSFB_MAX_YRES;
drm->mode_config.funcs = &mxsfb_mode_config_funcs;
drm->mode_config.helper_private = &mxsfb_mode_config_helpers;
drm_mode_config_reset(drm);
ret = platform_get_irq(pdev, 0);
if (ret < 0)
goto err_vblank;
mxsfb->irq = ret;
pm_runtime_get_sync(drm->dev);
ret = mxsfb_irq_install(drm, mxsfb->irq);
pm_runtime_put_sync(drm->dev);
if (ret < 0) {
dev_err(drm->dev, "Failed to install IRQ handler\n");
goto err_vblank;
}
drm_kms_helper_poll_init(drm);
platform_set_drvdata(pdev, drm);
drm_helper_hpd_irq_event(drm);
return 0;
err_vblank:
pm_runtime_disable(drm->dev);
return ret;
}
static void mxsfb_unload(struct drm_device *drm)
{
drm_kms_helper_poll_fini(drm);
drm_mode_config_cleanup(drm);
pm_runtime_get_sync(drm->dev);
mxsfb_irq_uninstall(drm);
pm_runtime_put_sync(drm->dev);
drm->dev_private = NULL;
pm_runtime_disable(drm->dev);
}
DEFINE_DRM_GEM_CMA_FOPS(fops);
static const struct drm_driver mxsfb_driver = {
.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
DRM_GEM_CMA_DRIVER_OPS,
.fops = &fops,
.name = "mxsfb-drm",
.desc = "MXSFB Controller DRM",
.date = "20160824",
.major = 1,
.minor = 0,
};
static const struct of_device_id mxsfb_dt_ids[] = {
{ .compatible = "fsl,imx23-lcdif", .data = &mxsfb_devdata[MXSFB_V3], },
{ .compatible = "fsl,imx28-lcdif", .data = &mxsfb_devdata[MXSFB_V4], },
{ .compatible = "fsl,imx6sx-lcdif", .data = &mxsfb_devdata[MXSFB_V6], },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxsfb_dt_ids);
static int mxsfb_probe(struct platform_device *pdev)
{
struct drm_device *drm;
const struct of_device_id *of_id =
of_match_device(mxsfb_dt_ids, &pdev->dev);
int ret;
if (!pdev->dev.of_node)
return -ENODEV;
drm = drm_dev_alloc(&mxsfb_driver, &pdev->dev);
if (IS_ERR(drm))
return PTR_ERR(drm);
ret = mxsfb_load(drm, of_id->data);
if (ret)
goto err_free;
ret = drm_dev_register(drm, 0);
if (ret)
goto err_unload;
drm_fbdev_generic_setup(drm, 32);
return 0;
err_unload:
mxsfb_unload(drm);
err_free:
drm_dev_put(drm);
return ret;
}
static int mxsfb_remove(struct platform_device *pdev)
{
struct drm_device *drm = platform_get_drvdata(pdev);
drm_dev_unregister(drm);
drm_atomic_helper_shutdown(drm);
mxsfb_unload(drm);
drm_dev_put(drm);
return 0;
}
static void mxsfb_shutdown(struct platform_device *pdev)
{
struct drm_device *drm = platform_get_drvdata(pdev);
drm_atomic_helper_shutdown(drm);
}
#ifdef CONFIG_PM_SLEEP
static int mxsfb_suspend(struct device *dev)
{
struct drm_device *drm = dev_get_drvdata(dev);
return drm_mode_config_helper_suspend(drm);
}
static int mxsfb_resume(struct device *dev)
{
struct drm_device *drm = dev_get_drvdata(dev);
return drm_mode_config_helper_resume(drm);
}
#endif
static const struct dev_pm_ops mxsfb_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mxsfb_suspend, mxsfb_resume)
};
static struct platform_driver mxsfb_platform_driver = {
.probe = mxsfb_probe,
.remove = mxsfb_remove,
.shutdown = mxsfb_shutdown,
.driver = {
.name = "mxsfb",
.of_match_table = mxsfb_dt_ids,
.pm = &mxsfb_pm_ops,
},
};
drm_module_platform_driver(mxsfb_platform_driver);
MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
MODULE_DESCRIPTION("Freescale MXS DRM/KMS driver");
MODULE_LICENSE("GPL");