omapdrm: hdmi4_cec: add OMAP4 HDMI CEC support

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 <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c

···
+/*
+ * 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 <[e-mail]>
+ *
+ * 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);
+}

drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h

···
+/*
+ * 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