// SPDX-License-Identifier: GPL-2.0-only
/*
* HDMI CEC
*
* Based on the CEC code from hdmi_ti_4xxx_ip.c from Android.
*
* Copyright (C) 2010-2011 Texas Instruments Incorporated - https://www.ti.com/
* Authors: Yong Zhi
* Mythri pk <[email protected]>
*
* Heavily modified to use the linux CEC framework:
*
* Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*/
#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;
if (msg.len > CEC_MAX_MSG_SIZE - 2)
msg.len = CEC_MAX_MSG_SIZE - 2;
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;
}
}
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 & 0x20) {
cec_transmit_done(core->adap, CEC_TX_STATUS_OK,
0, 0, 0, 0);
REG_FLD_MOD(core->base, HDMI_CEC_DBG_3, 0x1, 7, 7);
} else if (stat1 & 0x02) {
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);
REG_FLD_MOD(core->base, HDMI_CEC_DBG_3, 0x1, 7, 7);
}
if (stat0 & 0x02)
hdmi_cec_received_msg(core);
}
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);
REG_FLD_MOD(core->wp->base, HDMI_WP_CLK, 0, 5, 0);
hdmi4_core_disable(core);
return 0;
}
err = hdmi4_core_enable(core);
if (err)
return err;
/*
* Initialize CEC clock divider: CEC needs 2MHz clock hence
* set the divider to 24 to get 48/24=2MHz clock
*/
REG_FLD_MOD(core->wp->base, HDMI_WP_CLK, 0x18, 5, 0);
/* Clear TX FIFO */
if (!hdmi_cec_clear_tx_fifo(adap)) {
pr_err("cec-%s: could not clear TX FIFO\n", adap->name);
err = -EIO;
goto err_disable_clk;
}
/* Clear RX FIFO */
if (!hdmi_cec_clear_rx_fifo(adap)) {
pr_err("cec-%s: could not clear RX FIFO\n", adap->name);
err = -EIO;
goto err_disable_clk;
}
/* 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
* Receiver FIFO Not Empty event
*/
hdmi_write_reg(core->base, HDMI_CEC_INT_ENABLE_0, 0x22);
/*
* Enable CEC interrupts:
* Frame Retransmit Count Exceeded event
*/
hdmi_write_reg(core->base, HDMI_CEC_INT_ENABLE_1, 0x02);
/* 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;
err_disable_clk:
REG_FLD_MOD(core->wp->base, HDMI_WP_CLK, 0, 5, 0);
hdmi4_core_disable(core);
return err;
}
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;
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;
/* Disable clock initially, hdmi_cec_adap_enable() manages it */
REG_FLD_MOD(core->wp->base, HDMI_WP_CLK, 0, 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);
}
Codebase Browser
linux