[PATCH v11 4/6] i3c: master: svc: Add basic HDR mode support

[Frank Li <Frank.Li@nxp.com>]

Add basic HDR mode support for the svs I3C master driver.

Only support for private transfers and does not support sending CCC
commands in HDR mode.

Key differences:
- HDR uses commands (0x00-0x7F for write, 0x80-0xFF for read) to
distinguish transfer direction.
- HDR read/write commands must be written to FIFO before issuing the I3C
address command. The hardware automatically sends the standard CCC command
to enter HDR mode.
- HDR exit pattern must be sent instead of send a stop after transfer
completion.
- Read/write data size must be an even number.

Co-developed-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
change in v10
- remove !! at svc_cmd_is_read()
- move comments "IP" to next line

change in v7:
- add comment about why need check return value readl_poll_timeout()
in svc_i3c_master_emit_force_exit()
- add comment about why need udelay(1)
- remove reg = 0;
- chagne to use readl_poll_timeout_atomic();
- replace all i3c_priv_xfer with new i3c_xfer.

change in v4
- use hdr_cap.

change in v3
- rename to svc_cmd_is_read()
- rename to i3c_mode_to_svc_type()
- use local varible bool rnw to reduce change

change in v2
- support HDR DDR write
- rdterm unit is byte, not words (RM is wrong).
---
 drivers/i3c/master/svc-i3c-master.c | 96 ++++++++++++++++++++++++++++++++-----
 1 file changed, 83 insertions(+), 13 deletions(-)

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 7c516e05d0a1a118479ee3d8ea8ae37ae19fea57..42f678eac5b788abf7688845894df7b56ac08bec 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -40,11 +40,13 @@
 #define   SVC_I3C_MCTRL_REQUEST_NONE 0
 #define   SVC_I3C_MCTRL_REQUEST_START_ADDR 1
 #define   SVC_I3C_MCTRL_REQUEST_STOP 2
+#define   SVC_I3C_MCTRL_REQUEST_FORCE_EXIT 6
 #define   SVC_I3C_MCTRL_REQUEST_IBI_ACKNACK 3
 #define   SVC_I3C_MCTRL_REQUEST_PROC_DAA 4
 #define   SVC_I3C_MCTRL_REQUEST_AUTO_IBI 7
 #define   SVC_I3C_MCTRL_TYPE_I3C 0
 #define   SVC_I3C_MCTRL_TYPE_I2C BIT(4)
+#define   SVC_I3C_MCTRL_TYPE_DDR BIT(5)
 #define   SVC_I3C_MCTRL_IBIRESP_AUTO 0
 #define   SVC_I3C_MCTRL_IBIRESP_ACK_WITHOUT_BYTE 0
 #define   SVC_I3C_MCTRL_IBIRESP_ACK_WITH_BYTE BIT(7)
@@ -95,6 +97,7 @@
 #define SVC_I3C_MINTMASKED   0x098
 #define SVC_I3C_MERRWARN     0x09C
 #define   SVC_I3C_MERRWARN_NACK BIT(2)
+#define   SVC_I3C_MERRWARN_CRC	BIT(10)
 #define   SVC_I3C_MERRWARN_TIMEOUT BIT(20)
 #define SVC_I3C_MDMACTRL     0x0A0
 #define SVC_I3C_MDATACTRL    0x0AC
@@ -174,7 +177,7 @@ struct svc_i3c_cmd {
 	const void *out;
 	unsigned int len;
 	unsigned int actual_len;
-	struct i3c_priv_xfer *xfer;
+	struct i3c_xfer *xfer;
 	bool continued;
 };
 
@@ -389,7 +392,32 @@ svc_i3c_master_dev_from_addr(struct svc_i3c_master *master,
 
 static bool svc_cmd_is_read(u32 rnw_cmd, u32 type)
 {
-	return rnw_cmd;
+	return (type == SVC_I3C_MCTRL_TYPE_DDR) ? (rnw_cmd & 0x80) : rnw_cmd;
+}
+
+static void svc_i3c_master_emit_force_exit(struct svc_i3c_master *master)
+{
+	u32 reg;
+
+	writel(SVC_I3C_MCTRL_REQUEST_FORCE_EXIT, master->regs + SVC_I3C_MCTRL);
+
+	/*
+	 * Not need check error here because it is never happen at hardware.
+	 * IP just wait for few fclk cycle to complete DDR exit pattern. Even
+	 * though fclk stop, timeout happen here, the whole data actually
+	 * already finish transfer. The next command will be timeout because
+	 * wrong hardware state.
+	 */
+	readl_poll_timeout_atomic(master->regs + SVC_I3C_MSTATUS, reg,
+				  SVC_I3C_MSTATUS_MCTRLDONE(reg), 0, 1000);
+
+	/*
+	 * This delay is necessary after the emission of a stop, otherwise eg.
+	 * repeating IBIs do not get detected. There is a note in the manual
+	 * about it, stating that the stop condition might not be settled
+	 * correctly if a start condition follows too rapidly.
+	 */
+	udelay(1);
 }
 
 static void svc_i3c_master_emit_stop(struct svc_i3c_master *master)
@@ -521,7 +549,7 @@ static void svc_i3c_master_ibi_isr(struct svc_i3c_master *master)
 	 * cycle, leading to missed client IBI handlers.
 	 *
 	 * A typical scenario is when IBIWON occurs and bus arbitration is lost
-	 * at svc_i3c_master_priv_xfers().
+	 * at svc_i3c_master_i3c_xfers().
 	 *
 	 * Clear SVC_I3C_MINT_IBIWON before sending SVC_I3C_MCTRL_REQUEST_AUTO_IBI.
 	 */
@@ -801,6 +829,8 @@ static int svc_i3c_master_bus_init(struct i3c_master_controller *m)
 
 	info.dyn_addr = ret;
 
+	info.hdr_cap = I3C_CCC_HDR_MODE(I3C_HDR_DDR);
+
 	writel(SVC_MDYNADDR_VALID | SVC_MDYNADDR_ADDR(info.dyn_addr),
 	       master->regs + SVC_I3C_MDYNADDR);
 
@@ -1314,6 +1344,16 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 	/* clean SVC_I3C_MINT_IBIWON w1c bits */
 	writel(SVC_I3C_MINT_IBIWON, master->regs + SVC_I3C_MSTATUS);
 
+	if (xfer_type == SVC_I3C_MCTRL_TYPE_DDR) {
+		/* DDR command need prefill into FIFO */
+		writel(rnw_cmd, master->regs + SVC_I3C_MWDATAB);
+		if (!rnw) {
+			/* write data also need prefill into FIFO */
+			ret = svc_i3c_master_write(master, out, xfer_len);
+			if (ret)
+				goto emit_stop;
+		}
+	}
 
 	while (retry--) {
 		writel(SVC_I3C_MCTRL_REQUEST_START_ADDR |
@@ -1407,7 +1447,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 
 	if (rnw)
 		ret = svc_i3c_master_read(master, in, xfer_len);
-	else
+	else if (xfer_type != SVC_I3C_MCTRL_TYPE_DDR)
 		ret = svc_i3c_master_write(master, out, xfer_len);
 	if (ret < 0)
 		goto emit_stop;
@@ -1420,10 +1460,19 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 	if (ret)
 		goto emit_stop;
 
+	if (xfer_type == SVC_I3C_MCTRL_TYPE_DDR &&
+	    (readl(master->regs + SVC_I3C_MERRWARN) & SVC_I3C_MERRWARN_CRC)) {
+		ret = -ENXIO;
+		goto emit_stop;
+	}
+
 	writel(SVC_I3C_MINT_COMPLETE, master->regs + SVC_I3C_MSTATUS);
 
 	if (!continued) {
-		svc_i3c_master_emit_stop(master);
+		if (xfer_type != SVC_I3C_MCTRL_TYPE_DDR)
+			svc_i3c_master_emit_stop(master);
+		else
+			svc_i3c_master_emit_force_exit(master);
 
 		/* Wait idle if stop is sent. */
 		readl_poll_timeout(master->regs + SVC_I3C_MSTATUS, reg,
@@ -1433,7 +1482,11 @@ static int svc_i3c_master_xfer(struct svc_i3c_master *master,
 	return 0;
 
 emit_stop:
-	svc_i3c_master_emit_stop(master);
+	if (xfer_type != SVC_I3C_MCTRL_TYPE_DDR)
+		svc_i3c_master_emit_stop(master);
+	else
+		svc_i3c_master_emit_force_exit(master);
+
 	svc_i3c_master_clear_merrwarn(master);
 	svc_i3c_master_flush_fifo(master);
 
@@ -1480,6 +1533,11 @@ static void svc_i3c_master_dequeue_xfer(struct svc_i3c_master *master,
 	spin_unlock_irqrestore(&master->xferqueue.lock, flags);
 }
 
+static int i3c_mode_to_svc_type(enum i3c_xfer_mode mode)
+{
+	return (mode == I3C_SDR) ? SVC_I3C_MCTRL_TYPE_I3C : SVC_I3C_MCTRL_TYPE_DDR;
+}
+
 static void svc_i3c_master_start_xfer_locked(struct svc_i3c_master *master)
 {
 	struct svc_i3c_xfer *xfer = master->xferqueue.cur;
@@ -1669,9 +1727,8 @@ static int svc_i3c_master_send_ccc_cmd(struct i3c_master_controller *m,
 	return ret;
 }
 
-static int svc_i3c_master_priv_xfers(struct i3c_dev_desc *dev,
-				     struct i3c_priv_xfer *xfers,
-				     int nxfers)
+static int svc_i3c_master_i3c_xfers(struct i3c_dev_desc *dev, struct i3c_xfer *xfers,
+				    int nxfers, enum i3c_xfer_mode mode)
 {
 	struct i3c_master_controller *m = i3c_dev_get_master(dev);
 	struct svc_i3c_master *master = to_svc_i3c_master(m);
@@ -1679,19 +1736,32 @@ static int svc_i3c_master_priv_xfers(struct i3c_dev_desc *dev,
 	struct svc_i3c_xfer *xfer;
 	int ret, i;
 
+	if (mode != I3C_SDR) {
+		/*
+		 * Only support data size less than FIFO SIZE when using DDR
+		 * mode. First entry is cmd in FIFO, so actual available FIFO
+		 * for data is SVC_I3C_FIFO_SIZE - 2 since DDR only supports
+		 * even length.
+		 */
+		for (i = 0; i < nxfers; i++)
+			if (xfers[i].len > SVC_I3C_FIFO_SIZE - 2)
+				return -EINVAL;
+	}
+
 	xfer = svc_i3c_master_alloc_xfer(master, nxfers);
 	if (!xfer)
 		return -ENOMEM;
 
-	xfer->type = SVC_I3C_MCTRL_TYPE_I3C;
+	xfer->type = i3c_mode_to_svc_type(mode);
 
 	for (i = 0; i < nxfers; i++) {
+		u32 rnw_cmd = (mode == I3C_SDR) ? xfers[i].rnw : xfers[i].cmd;
+		bool rnw = svc_cmd_is_read(rnw_cmd, xfer->type);
 		struct svc_i3c_cmd *cmd = &xfer->cmds[i];
-		bool rnw = xfers[i].rnw;
 
 		cmd->xfer = &xfers[i];
 		cmd->addr = master->addrs[data->index];
-		cmd->rnw = rnw;
+		cmd->rnw_cmd = rnw_cmd;
 		cmd->in = rnw ? xfers[i].data.in : NULL;
 		cmd->out = rnw ? NULL : xfers[i].data.out;
 		cmd->len = xfers[i].len;
@@ -1890,7 +1960,7 @@ static const struct i3c_master_controller_ops svc_i3c_master_ops = {
 	.do_daa = svc_i3c_master_do_daa,
 	.supports_ccc_cmd = svc_i3c_master_supports_ccc_cmd,
 	.send_ccc_cmd = svc_i3c_master_send_ccc_cmd,
-	.priv_xfers = svc_i3c_master_priv_xfers,
+	.i3c_xfers = svc_i3c_master_i3c_xfers,
 	.i2c_xfers = svc_i3c_master_i2c_xfers,
 	.request_ibi = svc_i3c_master_request_ibi,
 	.free_ibi = svc_i3c_master_free_ibi,

-- 
2.34.1