[PATCH v7 3/4] drm/loongson: Add interrupt driver for LS7A.

From: Chenyang Li
Date: Sat Jun 25 2022 - 05:07:43 EST


Add LS7A DC vsync interrupt enable and close function, and
register irq_handler function interface.
Add vbrank event processing flow.

v4:
- Replace drm_irq_install with devm_request_irq.
- Delete the irq_ hooks in drm_driver.

v3:
- Improve code readability.
- Use the to_pci_dev function to get pci_dev.

v2:
- Added error handling in the loongson_drm_load function.

Signed-off-by: Chenyang Li <lichenyang@xxxxxxxxxxx>
---
drivers/gpu/drm/loongson/Makefile | 1 +
drivers/gpu/drm/loongson/loongson_crtc.c | 37 +++++++++++
drivers/gpu/drm/loongson/loongson_drv.c | 9 ++-
drivers/gpu/drm/loongson/loongson_drv.h | 10 +++
drivers/gpu/drm/loongson/loongson_irq.c | 84 ++++++++++++++++++++++++
5 files changed, 140 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/loongson/loongson_irq.c

diff --git a/drivers/gpu/drm/loongson/Makefile b/drivers/gpu/drm/loongson/Makefile
index 4a5fab7d000b..b083854d789b 100644
--- a/drivers/gpu/drm/loongson/Makefile
+++ b/drivers/gpu/drm/loongson/Makefile
@@ -10,5 +10,6 @@ loongson-y := loongson_connector.o \
loongson_drv.o \
loongson_encoder.o \
loongson_i2c.o \
+ loongson_irq.o \
loongson_plane.o
obj-$(CONFIG_DRM_LOONGSON) += loongson.o
diff --git a/drivers/gpu/drm/loongson/loongson_crtc.c b/drivers/gpu/drm/loongson/loongson_crtc.c
index 611378cef8e8..6a31ff911ce1 100644
--- a/drivers/gpu/drm/loongson/loongson_crtc.c
+++ b/drivers/gpu/drm/loongson/loongson_crtc.c
@@ -4,6 +4,7 @@
*/

#include <drm/drm_fourcc.h>
+#include <drm/drm_vblank.h>

#include "loongson_drv.h"

@@ -167,8 +168,14 @@ static void loongson_crtc_atomic_enable(struct drm_crtc *crtc,
struct loongson_crtc *lcrtc = to_loongson_crtc(crtc);
u32 reg_offset = lcrtc->reg_offset;

+ if (lcrtc->cfg_reg & CFG_ENABLE)
+ goto vblank_on;
+
lcrtc->cfg_reg |= CFG_ENABLE;
ls7a_mm_wreg(ldev, FB_CFG_REG + reg_offset, lcrtc->cfg_reg);
+
+vblank_on:
+ drm_crtc_vblank_on(crtc);
}

static void loongson_crtc_atomic_disable(struct drm_crtc *crtc,
@@ -181,6 +188,33 @@ static void loongson_crtc_atomic_disable(struct drm_crtc *crtc,

lcrtc->cfg_reg &= ~CFG_ENABLE;
ls7a_mm_wreg(ldev, FB_CFG_REG + reg_offset, lcrtc->cfg_reg);
+
+ spin_lock_irq(&crtc->dev->event_lock);
+ if (crtc->state->event) {
+ drm_crtc_send_vblank_event(crtc, crtc->state->event);
+ crtc->state->event = NULL;
+ }
+ spin_unlock_irq(&crtc->dev->event_lock);
+
+ drm_crtc_vblank_off(crtc);
+}
+
+static void loongson_crtc_atomic_flush(struct drm_crtc *crtc,
+ struct drm_atomic_state *state)
+{
+ struct drm_pending_vblank_event *event = crtc->state->event;
+
+ if (!event)
+ return;
+
+ crtc->state->event = NULL;
+
+ spin_lock_irq(&crtc->dev->event_lock);
+ if (drm_crtc_vblank_get(crtc) == 0)
+ drm_crtc_arm_vblank_event(crtc, event);
+ else
+ drm_crtc_send_vblank_event(crtc, event);
+ spin_unlock_irq(&crtc->dev->event_lock);
}

static enum drm_mode_status loongson_mode_valid(struct drm_crtc *crtc,
@@ -200,6 +234,7 @@ static enum drm_mode_status loongson_mode_valid(struct drm_crtc *crtc,

static const struct drm_crtc_helper_funcs loongson_crtc_helper_funcs = {
.mode_valid = loongson_mode_valid,
+ .atomic_flush = loongson_crtc_atomic_flush,
.atomic_enable = loongson_crtc_atomic_enable,
.atomic_disable = loongson_crtc_atomic_disable,
.mode_set_nofb = loongson_crtc_mode_set_nofb,
@@ -211,6 +246,8 @@ static const struct drm_crtc_funcs loongson_crtc_funcs = {
.reset = drm_atomic_helper_crtc_reset,
.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+ .enable_vblank = loongson_crtc_enable_vblank,
+ .disable_vblank = loongson_crtc_disable_vblank,
};

int loongson_crtc_init(struct loongson_device *ldev, int index)
diff --git a/drivers/gpu/drm/loongson/loongson_drv.c b/drivers/gpu/drm/loongson/loongson_drv.c
index 2e3ef6193767..1d6f35e78813 100644
--- a/drivers/gpu/drm/loongson/loongson_drv.c
+++ b/drivers/gpu/drm/loongson/loongson_drv.c
@@ -23,9 +23,10 @@
/* Interface history:
* 0.1 - original.
* 0.2 - add i2c and connector detect.
+ * 0.3 - Vblank and vsync interrupt support.
*/
#define DRIVER_MAJOR 0
-#define DRIVER_MINOR 2
+#define DRIVER_MINOR 3

static const struct drm_mode_config_funcs loongson_mode_funcs = {
.fb_create = drm_gem_fb_create,
@@ -167,6 +168,12 @@ static int loongson_driver_init(struct drm_device *dev)
goto err;
}

+ ret = loongson_irq_init(ldev);
+ if (ret) {
+ dev_err(dev->dev, "Fatal error during irq init: %d\n", ret);
+ goto err;
+ }
+
drm_kms_helper_poll_init(dev);
drm_mode_config_reset(dev);

diff --git a/drivers/gpu/drm/loongson/loongson_drv.h b/drivers/gpu/drm/loongson/loongson_drv.h
index 5be29d2d1a49..af47e68487fd 100644
--- a/drivers/gpu/drm/loongson/loongson_drv.h
+++ b/drivers/gpu/drm/loongson/loongson_drv.h
@@ -40,6 +40,7 @@
#define FB_HSYNC_REG (0x1420)
#define FB_VDISPLAY_REG (0x1480)
#define FB_VSYNC_REG (0x14a0)
+#define FB_INT_REG (0x1570)

#define CFG_FMT GENMASK(2, 0)
#define CFG_FBSWITCH BIT(7)
@@ -51,6 +52,10 @@
#define FB_PANCFG_DEF 0x80001311
#define FB_HSYNC_PULSE (1 << 30)
#define FB_VSYNC_PULSE (1 << 30)
+#define FB_VSYNC1_ENABLE (1 << 16)
+#define FB_VSYNC0_ENABLE (1 << 18)
+#define FB_VSYNC1_INT (1 << 0)
+#define FB_VSYNC0_INT (1 << 2)

/* PIX PLL */
#define LOOPC_MIN 24
@@ -128,6 +133,11 @@ struct loongson_plane *loongson_plane_init(struct drm_device *dev, int index);
/* i2c */
int loongson_dc_gpio_init(struct loongson_device *ldev);

+/* irq */
+int loongson_irq_init(struct loongson_device *ldev);
+int loongson_crtc_enable_vblank(struct drm_crtc *crtc);
+void loongson_crtc_disable_vblank(struct drm_crtc *crtc);
+
/* device */
u32 loongson_gpu_offset(struct drm_plane_state *state,
struct loongson_device *dev);
diff --git a/drivers/gpu/drm/loongson/loongson_irq.c b/drivers/gpu/drm/loongson/loongson_irq.c
new file mode 100644
index 000000000000..ba215d585dc7
--- /dev/null
+++ b/drivers/gpu/drm/loongson/loongson_irq.c
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+
+#include <linux/pci.h>
+
+#include <drm/drm_vblank.h>
+
+#include "loongson_drv.h"
+
+static irqreturn_t loongson_irq_handler(int irq, void *arg)
+{
+ struct drm_device *dev = (struct drm_device *) arg;
+ struct loongson_device *ldev = to_loongson_device(dev);
+ struct loongson_crtc *lcrtc;
+ u32 val;
+
+ val = ls7a_mm_rreg(ldev, FB_INT_REG);
+ ls7a_mm_wreg(ldev, FB_INT_REG, val & (0xffff << 16));
+
+ if (val & FB_VSYNC0_INT)
+ lcrtc = ldev->mode_info[0].crtc;
+ else if (val & FB_VSYNC1_INT)
+ lcrtc = ldev->mode_info[1].crtc;
+
+ drm_crtc_handle_vblank(&lcrtc->base);
+
+ return IRQ_HANDLED;
+}
+
+int loongson_irq_init(struct loongson_device *ldev)
+{
+ int ret;
+ struct drm_device *dev = &ldev->dev;
+ int irq = to_pci_dev(dev->dev)->irq;
+
+ ret = drm_vblank_init(dev, ldev->num_crtc);
+ if (ret) {
+ dev_err(dev->dev, "Fatal error during vblank init: %d\n", ret);
+ return ret;
+ }
+ DRM_INFO("drm vblank init finished\n");
+
+ ret = devm_request_irq(dev->dev, irq, loongson_irq_handler, 0,
+ "loongson-drm", dev);
+ if (ret) {
+ dev_err(dev->dev, "Fatal error during irq install: %d\n", ret);
+ return ret;
+ }
+ DRM_INFO("loongson irq initialized\n");
+
+ return 0;
+}
+
+int loongson_crtc_enable_vblank(struct drm_crtc *crtc)
+{
+ struct loongson_crtc *lcrtc = to_loongson_crtc(crtc);
+ struct loongson_device *ldev = lcrtc->ldev;
+ u32 reg_val = ls7a_mm_rreg(ldev, FB_INT_REG);
+
+ if (lcrtc->crtc_id)
+ reg_val |= FB_VSYNC1_ENABLE;
+ else
+ reg_val |= FB_VSYNC0_ENABLE;
+
+ ls7a_mm_wreg(ldev, FB_INT_REG, reg_val);
+
+ return 0;
+}
+
+void loongson_crtc_disable_vblank(struct drm_crtc *crtc)
+{
+ struct loongson_crtc *lcrtc = to_loongson_crtc(crtc);
+ struct loongson_device *ldev = lcrtc->ldev;
+ u32 reg_val = ls7a_mm_rreg(ldev, FB_INT_REG);
+
+ if (lcrtc->crtc_id)
+ reg_val &= ~FB_VSYNC1_ENABLE;
+ else
+ reg_val &= ~FB_VSYNC0_ENABLE;
+
+ ls7a_mm_wreg(ldev, FB_INT_REG, reg_val);
+}
--
2.25.1