Downstream version of RK3588 U-Boot uses customized TF-A that remaps
HDMIRX hardware interrupt, routing it via firmware that isn't supported
by upstream driver.

Detect broken interrupt and print a clarifying error message about a need
to use open-source TF-A with this driver.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 .../platform/synopsys/hdmirx/snps_hdmirx.c    | 85 ++++++++++++++++++-
 .../platform/synopsys/hdmirx/snps_hdmirx.h    |  2 +
 2 files changed, 85 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
index b7d278b3889f..faca601d72a4 100644
--- a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
+++ b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.c
@@ -138,6 +138,7 @@ struct snps_hdmirx_dev {
 	struct clk_bulk_data *clks;
 	struct regmap *grf;
 	struct regmap *vo1_grf;
+	struct completion cr_read_done;
 	struct completion cr_write_done;
 	struct completion timer_base_lock;
 	struct completion avi_pkt_rcv;
@@ -796,6 +797,41 @@ static int wait_reg_bit_status(struct snps_hdmirx_dev *hdmirx_dev, u32 reg,
 	return 0;
 }
 
+static int hdmirx_phy_register_read(struct snps_hdmirx_dev *hdmirx_dev,
+				    u32 phy_reg, u32 *val)
+{
+	struct device *dev = hdmirx_dev->dev;
+	u32 status;
+
+	reinit_completion(&hdmirx_dev->cr_read_done);
+	/* clear irq status */
+	hdmirx_clear_interrupt(hdmirx_dev, MAINUNIT_2_INT_CLEAR, 0xffffffff);
+	/* en irq */
+	hdmirx_update_bits(hdmirx_dev, MAINUNIT_2_INT_MASK_N,
+			   PHYCREG_CR_READ_DONE, PHYCREG_CR_READ_DONE);
+	/* write phy reg addr */
+	hdmirx_writel(hdmirx_dev, PHYCREG_CONFIG1, phy_reg);
+	/* config read enable */
+	hdmirx_writel(hdmirx_dev, PHYCREG_CONTROL, PHYCREG_CR_PARA_READ_P);
+
+	if (!wait_for_completion_timeout(&hdmirx_dev->cr_read_done,
+					 msecs_to_jiffies(20))) {
+		dev_err(dev, "%s wait cr read done failed\n", __func__);
+		return -ETIMEDOUT;
+	}
+
+	/* read phy reg value */
+	status = hdmirx_readl(hdmirx_dev, PHYCREG_STATUS);
+	if (!(status & PHYCREG_CR_PARA_DATAVALID)) {
+		dev_err(dev, "%s cr read failed\n", __func__);
+		return -EINVAL;
+	}
+
+	*val = status & PHYCREG_CR_PARA_RD_DATA_MASK;
+
+	return 0;
+}
+
 static int hdmirx_phy_register_write(struct snps_hdmirx_dev *hdmirx_dev,
 				     u32 phy_reg, u32 val)
 {
@@ -1814,6 +1850,13 @@ static void mainunit_2_int_handler(struct snps_hdmirx_dev *hdmirx_dev,
 		*handled = true;
 	}
 
+	if (status & PHYCREG_CR_READ_DONE) {
+		hdmirx_update_bits(hdmirx_dev, MAINUNIT_2_INT_MASK_N,
+				   PHYCREG_CR_READ_DONE, 0);
+		complete(&hdmirx_dev->cr_read_done);
+		*handled = true;
+	}
+
 	if (status & TMDSVALID_STABLE_CHG) {
 		process_signal_change(hdmirx_dev);
 		v4l2_dbg(2, debug, v4l2_dev, "%s: TMDSVALID_STABLE_CHG\n", __func__);
@@ -2313,18 +2356,52 @@ static void hdmirx_disable_all_interrupts(struct snps_hdmirx_dev *hdmirx_dev)
 	hdmirx_clear_interrupt(hdmirx_dev, CEC_INT_CLEAR, 0xffffffff);
 }
 
-static void hdmirx_init(struct snps_hdmirx_dev *hdmirx_dev)
+static int hdmirx_detect_broken_interrupt(struct snps_hdmirx_dev *hdmirx_dev)
+{
+	int err;
+	u32 val;
+
+	enable_irq(hdmirx_dev->hdmi_irq);
+
+	hdmirx_writel(hdmirx_dev, PHYCREG_CONFIG0, 0x3);
+
+	err = hdmirx_phy_register_read(hdmirx_dev,
+				       HDMIPCS_DIG_CTRL_PATH_MAIN_FSM_FSM_CONFIG,
+				       &val);
+
+	disable_irq(hdmirx_dev->hdmi_irq);
+
+	if (err)
+		return dev_err_probe(hdmirx_dev->dev, err,
+				     "interrupt not functioning, open-source TF-A is required by this driver\n");
+
+	return 0;
+}
+
+static int hdmirx_init(struct snps_hdmirx_dev *hdmirx_dev)
 {
+	int ret;
+
 	hdmirx_update_bits(hdmirx_dev, PHY_CONFIG, PHY_RESET | PHY_PDDQ, 0);
 
 	regmap_write(hdmirx_dev->vo1_grf, VO1_GRF_VO1_CON2,
 		     (HDMIRX_SDAIN_MSK | HDMIRX_SCLIN_MSK) |
 		     ((HDMIRX_SDAIN_MSK | HDMIRX_SCLIN_MSK) << 16));
+
+	/*
+	 * RK3588 downstream version of TF-A remaps HDMIRX interrupt and
+	 * requires use of a vendor-specific FW API by the driver that we
+	 * don't support in this driver.
+	 */
+	ret = hdmirx_detect_broken_interrupt(hdmirx_dev);
+
 	/*
 	 * Some interrupts are enabled by default, so we disable
 	 * all interrupts and clear interrupts status first.
 	 */
 	hdmirx_disable_all_interrupts(hdmirx_dev);
+
+	return ret;
 }
 
 /* hdmi-4k-300mhz EDID produced by v4l2-ctl tool */
@@ -2610,6 +2687,7 @@ static int hdmirx_probe(struct platform_device *pdev)
 	mutex_init(&hdmirx_dev->work_lock);
 	spin_lock_init(&hdmirx_dev->rst_lock);
 
+	init_completion(&hdmirx_dev->cr_read_done);
 	init_completion(&hdmirx_dev->cr_write_done);
 	init_completion(&hdmirx_dev->timer_base_lock);
 	init_completion(&hdmirx_dev->avi_pkt_rcv);
@@ -2623,7 +2701,10 @@ static int hdmirx_probe(struct platform_device *pdev)
 	hdmirx_dev->timings = cea640x480;
 
 	hdmirx_enable(dev);
-	hdmirx_init(hdmirx_dev);
+
+	ret = hdmirx_init(hdmirx_dev);
+	if (ret)
+		goto err_pm;
 
 	v4l2_dev = &hdmirx_dev->v4l2_dev;
 	strscpy(v4l2_dev->name, dev_name(dev), sizeof(v4l2_dev->name));
diff --git a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.h b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.h
index 220ab99ca611..a719439d3ca0 100644
--- a/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.h
+++ b/drivers/media/platform/synopsys/hdmirx/snps_hdmirx.h
@@ -114,6 +114,8 @@
 #define PHYCREG_CR_PARA_WRITE_P			BIT(1)
 #define PHYCREG_CR_PARA_READ_P			BIT(0)
 #define PHYCREG_STATUS				0x00f4
+#define PHYCREG_CR_PARA_DATAVALID		BIT(24)
+#define PHYCREG_CR_PARA_RD_DATA_MASK		GENMASK(15, 0)
 
 #define MAINUNIT_STATUS				0x0150
 #define TMDSVALID_STABLE_ST			BIT(1)
-- 
2.51.0