[PATCH 7/8] omapdrm: hdmi4_cec: add OMAP4 HDMI CEC support

Hans Verkuil hverkuil at xs4all.nl
Fri Apr 14 10:25:11 UTC 2017


From: Hans Verkuil <hans.verkuil at cisco.com>

Add the source and header for the OMAP4 HDMI CEC support.

This code is not yet hooked up, that will happen in the next patch.

Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
---
 drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c | 381 ++++++++++++++++++++++++++++++++
 drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h |  55 +++++
 2 files changed, 436 insertions(+)
 create mode 100644 drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c
 create mode 100644 drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h

diff --git a/drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c b/drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c
new file mode 100644
index 000000000000..d86873f2abe6
--- /dev/null
+++ b/drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c
@@ -0,0 +1,381 @@
+/*
+ * HDMI CEC
+ *
+ * Based on the CEC code from hdmi_ti_4xxx_ip.c from Android.
+ *
+ * Copyright (C) 2010-2011 Texas Instruments Incorporated - http://www.ti.com/
+ * Authors: Yong Zhi
+ *	Mythri pk <mythripk at ti.com>
+ *
+ * Heavily modified to use the linux CEC framework:
+ *
+ * Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "dss.h"
+#include "hdmi.h"
+#include "hdmi4_core.h"
+#include "hdmi4_cec.h"
+
+/* HDMI CEC */
+#define HDMI_CEC_DEV_ID                         0x900
+#define HDMI_CEC_SPEC                           0x904
+
+/* Not really a debug register, more a low-level control register */
+#define HDMI_CEC_DBG_3                          0x91C
+#define HDMI_CEC_TX_INIT                        0x920
+#define HDMI_CEC_TX_DEST                        0x924
+#define HDMI_CEC_SETUP                          0x938
+#define HDMI_CEC_TX_COMMAND                     0x93C
+#define HDMI_CEC_TX_OPERAND                     0x940
+#define HDMI_CEC_TRANSMIT_DATA                  0x97C
+#define HDMI_CEC_CA_7_0                         0x988
+#define HDMI_CEC_CA_15_8                        0x98C
+#define HDMI_CEC_INT_STATUS_0                   0x998
+#define HDMI_CEC_INT_STATUS_1                   0x99C
+#define HDMI_CEC_INT_ENABLE_0                   0x990
+#define HDMI_CEC_INT_ENABLE_1                   0x994
+#define HDMI_CEC_RX_CONTROL                     0x9B0
+#define HDMI_CEC_RX_COUNT                       0x9B4
+#define HDMI_CEC_RX_CMD_HEADER                  0x9B8
+#define HDMI_CEC_RX_COMMAND                     0x9BC
+#define HDMI_CEC_RX_OPERAND                     0x9C0
+
+#define HDMI_CEC_TX_FIFO_INT_MASK		0x64
+#define HDMI_CEC_RETRANSMIT_CNT_INT_MASK	0x2
+
+#define HDMI_CORE_CEC_RETRY    200
+
+static void hdmi_cec_received_msg(struct hdmi_core_data *core)
+{
+	u32 cnt = hdmi_read_reg(core->base, HDMI_CEC_RX_COUNT) & 0xff;
+
+	/* While there are CEC frames in the FIFO */
+	while (cnt & 0x70) {
+		/* and the frame doesn't have an error */
+		if (!(cnt & 0x80)) {
+			struct cec_msg msg = {};
+			unsigned int i;
+
+			/* then read the message */
+			msg.len = cnt & 0xf;
+			msg.msg[0] = hdmi_read_reg(core->base,
+						   HDMI_CEC_RX_CMD_HEADER);
+			msg.msg[1] = hdmi_read_reg(core->base,
+						   HDMI_CEC_RX_COMMAND);
+			for (i = 0; i < msg.len; i++) {
+				unsigned int reg = HDMI_CEC_RX_OPERAND + i * 4;
+
+				msg.msg[2 + i] =
+					hdmi_read_reg(core->base, reg);
+			}
+			msg.len += 2;
+			cec_received_msg(core->adap, &msg);
+		}
+		/* Clear the current frame from the FIFO */
+		hdmi_write_reg(core->base, HDMI_CEC_RX_CONTROL, 1);
+		/* Wait until the current frame is cleared */
+		while (hdmi_read_reg(core->base, HDMI_CEC_RX_CONTROL) & 1)
+			udelay(1);
+		/*
+		 * Re-read the count register and loop to see if there are
+		 * more messages in the FIFO.
+		 */
+		cnt = hdmi_read_reg(core->base, HDMI_CEC_RX_COUNT) & 0xff;
+	}
+}
+
+static void hdmi_cec_transmit_fifo_empty(struct hdmi_core_data *core, u32 stat1)
+{
+	if (stat1 & 2) {
+		u32 dbg3 = hdmi_read_reg(core->base, HDMI_CEC_DBG_3);
+
+		cec_transmit_done(core->adap,
+				  CEC_TX_STATUS_NACK |
+				  CEC_TX_STATUS_MAX_RETRIES,
+				  0, (dbg3 >> 4) & 7, 0, 0);
+	} else if (stat1 & 1) {
+		cec_transmit_done(core->adap,
+				  CEC_TX_STATUS_ARB_LOST |
+				  CEC_TX_STATUS_MAX_RETRIES,
+				  0, 0, 0, 0);
+	} else if (stat1 == 0) {
+		cec_transmit_done(core->adap, CEC_TX_STATUS_OK,
+				  0, 0, 0, 0);
+	}
+}
+
+void hdmi4_cec_irq(struct hdmi_core_data *core)
+{
+	u32 stat0 = hdmi_read_reg(core->base, HDMI_CEC_INT_STATUS_0);
+	u32 stat1 = hdmi_read_reg(core->base, HDMI_CEC_INT_STATUS_1);
+
+	hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_0, stat0);
+	hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_1, stat1);
+
+	if (stat0 & 0x40)
+		REG_FLD_MOD(core->base, HDMI_CEC_DBG_3, 0x1, 7, 7);
+	else if (stat0 & 0x24)
+		hdmi_cec_transmit_fifo_empty(core, stat1);
+	if (stat1 & 2) {
+		u32 dbg3 = hdmi_read_reg(core->base, HDMI_CEC_DBG_3);
+
+		cec_transmit_done(core->adap,
+				  CEC_TX_STATUS_NACK |
+				  CEC_TX_STATUS_MAX_RETRIES,
+				  0, (dbg3 >> 4) & 7, 0, 0);
+	} else if (stat1 & 1) {
+		cec_transmit_done(core->adap,
+				  CEC_TX_STATUS_ARB_LOST |
+				  CEC_TX_STATUS_MAX_RETRIES,
+				  0, 0, 0, 0);
+	}
+	if (stat0 & 0x02)
+		hdmi_cec_received_msg(core);
+	if (stat1 & 0x3)
+		REG_FLD_MOD(core->base, HDMI_CEC_DBG_3, 0x1, 7, 7);
+}
+
+static bool hdmi_cec_clear_tx_fifo(struct cec_adapter *adap)
+{
+	struct hdmi_core_data *core = cec_get_drvdata(adap);
+	int retry = HDMI_CORE_CEC_RETRY;
+	int temp;
+
+	REG_FLD_MOD(core->base, HDMI_CEC_DBG_3, 0x1, 7, 7);
+	while (retry) {
+		temp = hdmi_read_reg(core->base, HDMI_CEC_DBG_3);
+		if (FLD_GET(temp, 7, 7) == 0)
+			break;
+		retry--;
+	}
+	return retry != 0;
+}
+
+static bool hdmi_cec_clear_rx_fifo(struct cec_adapter *adap)
+{
+	struct hdmi_core_data *core = cec_get_drvdata(adap);
+	int retry = HDMI_CORE_CEC_RETRY;
+	int temp;
+
+	hdmi_write_reg(core->base, HDMI_CEC_RX_CONTROL, 0x3);
+	retry = HDMI_CORE_CEC_RETRY;
+	while (retry) {
+		temp = hdmi_read_reg(core->base, HDMI_CEC_RX_CONTROL);
+		if (FLD_GET(temp, 1, 0) == 0)
+			break;
+		retry--;
+	}
+	return retry != 0;
+}
+
+static int hdmi_cec_adap_enable(struct cec_adapter *adap, bool enable)
+{
+	struct hdmi_core_data *core = cec_get_drvdata(adap);
+	int temp, err;
+
+	if (!enable) {
+		hdmi_write_reg(core->base, HDMI_CEC_INT_ENABLE_0, 0);
+		hdmi_write_reg(core->base, HDMI_CEC_INT_ENABLE_1, 0);
+		REG_FLD_MOD(core->base, HDMI_CORE_SYS_INTR_UNMASK4, 0, 3, 3);
+		hdmi_wp_clear_irqenable(core->wp, HDMI_IRQ_CORE);
+		hdmi_wp_set_irqstatus(core->wp, HDMI_IRQ_CORE);
+		hdmi4_core_disable(NULL);
+		return 0;
+	}
+	err = hdmi4_core_enable(NULL);
+	if (err)
+		return err;
+
+	/* Clear TX FIFO */
+	if (!hdmi_cec_clear_tx_fifo(adap)) {
+		pr_err("cec-%s: could not clear TX FIFO\n", adap->name);
+		return -EIO;
+	}
+
+	/* Clear RX FIFO */
+	if (!hdmi_cec_clear_rx_fifo(adap)) {
+		pr_err("cec-%s: could not clear RX FIFO\n", adap->name);
+		return -EIO;
+	}
+
+	/* Clear CEC interrupts */
+	hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_1,
+		hdmi_read_reg(core->base, HDMI_CEC_INT_STATUS_1));
+	hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_0,
+		hdmi_read_reg(core->base, HDMI_CEC_INT_STATUS_0));
+
+	/* Enable HDMI core interrupts */
+	hdmi_wp_set_irqenable(core->wp, HDMI_IRQ_CORE);
+	/* Unmask CEC interrupt */
+	REG_FLD_MOD(core->base, HDMI_CORE_SYS_INTR_UNMASK4, 0x1, 3, 3);
+	/*
+	 * Enable CEC interrupts:
+	 * Transmit Buffer Full/Empty Change event
+	 * Transmitter FIFO Empty event
+	 * Receiver FIFO Not Empty event
+	 */
+	hdmi_write_reg(core->base, HDMI_CEC_INT_ENABLE_0, 0x26);
+	/*
+	 * Enable CEC interrupts:
+	 * RX FIFO Overrun Error event
+	 * Short Pulse Detected event
+	 * Frame Retransmit Count Exceeded event
+	 * Start Bit Irregularity event
+	 */
+	hdmi_write_reg(core->base, HDMI_CEC_INT_ENABLE_1, 0x0f);
+
+	/* cec calibration enable (self clearing) */
+	hdmi_write_reg(core->base, HDMI_CEC_SETUP, 0x03);
+	msleep(20);
+	hdmi_write_reg(core->base, HDMI_CEC_SETUP, 0x04);
+
+	temp = hdmi_read_reg(core->base, HDMI_CEC_SETUP);
+	if (FLD_GET(temp, 4, 4) != 0) {
+		temp = FLD_MOD(temp, 0, 4, 4);
+		hdmi_write_reg(core->base, HDMI_CEC_SETUP, temp);
+
+		/*
+		 * If we enabled CEC in middle of a CEC message on the bus,
+		 * we could have start bit irregularity and/or short
+		 * pulse event. Clear them now.
+		 */
+		temp = hdmi_read_reg(core->base, HDMI_CEC_INT_STATUS_1);
+		temp = FLD_MOD(0x0, 0x5, 2, 0);
+		hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_1, temp);
+	}
+	return 0;
+}
+
+static int hdmi_cec_adap_log_addr(struct cec_adapter *adap, u8 log_addr)
+{
+	struct hdmi_core_data *core = cec_get_drvdata(adap);
+	u32 v;
+
+	if (log_addr == CEC_LOG_ADDR_INVALID) {
+		hdmi_write_reg(core->base, HDMI_CEC_CA_7_0, 0);
+		hdmi_write_reg(core->base, HDMI_CEC_CA_15_8, 0);
+		return 0;
+	}
+	if (log_addr <= 7) {
+		v = hdmi_read_reg(core->base, HDMI_CEC_CA_7_0);
+		v |= 1 << log_addr;
+		hdmi_write_reg(core->base, HDMI_CEC_CA_7_0, v);
+	} else {
+		v = hdmi_read_reg(core->base, HDMI_CEC_CA_15_8);
+		v |= 1 << (log_addr - 8);
+		hdmi_write_reg(core->base, HDMI_CEC_CA_15_8, v);
+	}
+	return 0;
+}
+
+static int hdmi_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
+				   u32 signal_free_time, struct cec_msg *msg)
+{
+	struct hdmi_core_data *core = cec_get_drvdata(adap);
+	int temp;
+	u32 i;
+
+	/* Clear TX FIFO */
+	if (!hdmi_cec_clear_tx_fifo(adap)) {
+		pr_err("cec-%s: could not clear TX FIFO for transmit\n",
+		       adap->name);
+		return -EIO;
+	}
+
+	/* Clear TX interrupts */
+	hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_0,
+		       HDMI_CEC_TX_FIFO_INT_MASK);
+
+	hdmi_write_reg(core->base, HDMI_CEC_INT_STATUS_1,
+		       HDMI_CEC_RETRANSMIT_CNT_INT_MASK);
+
+	/* Set the retry count */
+	REG_FLD_MOD(core->base, HDMI_CEC_DBG_3, attempts - 1, 6, 4);
+
+	/* Set the initiator addresses */
+	hdmi_write_reg(core->base, HDMI_CEC_TX_INIT, cec_msg_initiator(msg));
+
+	/* Set destination id */
+	temp = cec_msg_destination(msg);
+	if (msg->len == 1)
+		temp |= 0x80;
+	hdmi_write_reg(core->base, HDMI_CEC_TX_DEST, temp);
+	if (msg->len == 1)
+		return 0;
+
+	/* Setup command and arguments for the command */
+	hdmi_write_reg(core->base, HDMI_CEC_TX_COMMAND, msg->msg[1]);
+
+	for (i = 0; i < msg->len - 2; i++)
+		hdmi_write_reg(core->base, HDMI_CEC_TX_OPERAND + i * 4,
+			       msg->msg[2 + i]);
+
+	/* Operand count */
+	hdmi_write_reg(core->base, HDMI_CEC_TRANSMIT_DATA,
+		       (msg->len - 2) | 0x10);
+	return 0;
+}
+
+static const struct cec_adap_ops hdmi_cec_adap_ops = {
+	.adap_enable = hdmi_cec_adap_enable,
+	.adap_log_addr = hdmi_cec_adap_log_addr,
+	.adap_transmit = hdmi_cec_adap_transmit,
+};
+
+void hdmi4_cec_set_phys_addr(struct hdmi_core_data *core, u16 pa)
+{
+	cec_s_phys_addr(core->adap, pa, false);
+}
+
+int hdmi4_cec_init(struct platform_device *pdev, struct hdmi_core_data *core,
+		  struct hdmi_wp_data *wp)
+{
+	const u32 caps = CEC_CAP_TRANSMIT | CEC_CAP_LOG_ADDRS |
+			 CEC_CAP_PASSTHROUGH | CEC_CAP_RC;
+	unsigned int ret;
+
+	core->adap = cec_allocate_adapter(&hdmi_cec_adap_ops, core,
+		"omap4", caps, CEC_MAX_LOG_ADDRS);
+	ret = PTR_ERR_OR_ZERO(core->adap);
+	if (ret < 0)
+		return ret;
+	core->wp = wp;
+
+	/*
+	 * Initialize CEC clock divider: CEC needs 2MHz clock hence
+	 * set the devider to 24 to get 48/24=2MHz clock
+	 */
+	REG_FLD_MOD(core->wp->base, HDMI_WP_CLK, 0x18, 5, 0);
+
+	ret = cec_register_adapter(core->adap, &pdev->dev);
+	if (ret < 0) {
+		cec_delete_adapter(core->adap);
+		return ret;
+	}
+	return 0;
+}
+
+void hdmi4_cec_uninit(struct hdmi_core_data *core)
+{
+	cec_unregister_adapter(core->adap);
+}
diff --git a/drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h b/drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h
new file mode 100644
index 000000000000..0292337c97cc
--- /dev/null
+++ b/drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h
@@ -0,0 +1,55 @@
+/*
+ * HDMI header definition for OMAP4 HDMI CEC IP
+ *
+ * Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ *
+ * This program is free software; you may redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _HDMI4_CEC_H_
+#define _HDMI4_CEC_H_
+
+struct hdmi_core_data;
+struct hdmi_wp_data;
+struct platform_device;
+
+/* HDMI CEC funcs */
+#ifdef CONFIG_OMAP4_DSS_HDMI_CEC
+void hdmi4_cec_set_phys_addr(struct hdmi_core_data *core, u16 pa);
+void hdmi4_cec_irq(struct hdmi_core_data *core);
+int hdmi4_cec_init(struct platform_device *pdev, struct hdmi_core_data *core,
+		  struct hdmi_wp_data *wp);
+void hdmi4_cec_uninit(struct hdmi_core_data *core);
+#else
+static inline void hdmi4_cec_set_phys_addr(struct hdmi_core_data *core, u16 pa)
+{
+}
+
+static inline void hdmi4_cec_irq(struct hdmi_core_data *core)
+{
+}
+
+static inline int hdmi4_cec_init(struct platform_device *pdev,
+				struct hdmi_core_data *core,
+				struct hdmi_wp_data *wp)
+{
+	return 0;
+}
+
+static inline void hdmi4_cec_uninit(struct hdmi_core_data *core)
+{
+}
+#endif
+
+#endif
-- 
2.11.0



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