[PATCH 2/2] i3c: master: cdns: add support for mastership request to Cadence I3C master driver.

[Przemyslaw Gaj <pgaj@cadence.com>]

This patch adds support for mastership request to Cadence I3C master driver.

Signed-off-by: Przemyslaw Gaj <pgaj@cadence.com>
---
 drivers/i3c/master/i3c-master-cdns.c | 316 ++++++++++++++++++++++++++++++-----
 1 file changed, 271 insertions(+), 45 deletions(-)

diff --git a/drivers/i3c/master/i3c-master-cdns.c b/drivers/i3c/master/i3c-master-cdns.c
index 02a8297..a33f3a6 100644
--- a/drivers/i3c/master/i3c-master-cdns.c
+++ b/drivers/i3c/master/i3c-master-cdns.c
@@ -157,6 +157,7 @@
 #define SLV_IMR				0x48
 #define SLV_ICR				0x4c
 #define SLV_ISR				0x50
+#define SLV_INT_DEFSLVS			BIT(21)
 #define SLV_INT_TM			BIT(20)
 #define SLV_INT_ERROR			BIT(19)
 #define SLV_INT_EVENT_UP		BIT(18)
@@ -390,6 +391,10 @@ struct cdns_i3c_xfer {
 
 struct cdns_i3c_master {
 	struct work_struct hj_work;
+	struct {
+		struct work_struct handover_work;
+		u32 ibir;
+	} mastership;
 	struct i3c_master_controller base;
 	u32 free_rr_slots;
 	unsigned int maxdevs;
@@ -664,6 +669,89 @@ static void cdns_i3c_master_unqueue_xfer(struct cdns_i3c_master *master,
 	spin_unlock_irqrestore(&master->xferqueue.lock, flags);
 }
 
+static void
+cdns_i3c_master_i3c_dev_rr_to_info(struct cdns_i3c_master *master,
+				   unsigned int slot,
+				   struct i3c_device_info *info)
+{
+	u32 rr;
+
+	memset(info, 0, sizeof(*info));
+	rr = readl(master->regs + DEV_ID_RR0(slot));
+	info->dyn_addr = DEV_ID_RR0_GET_DEV_ADDR(rr);
+	rr = readl(master->regs + DEV_ID_RR2(slot));
+	info->dcr = rr;
+	info->bcr = rr >> 8;
+	info->pid = rr >> 16;
+	info->pid |= (u64)readl(master->regs + DEV_ID_RR1(slot)) << 16;
+}
+
+static void
+cdns_i3c_master_i2c_dev_rr_to_boardinfo(struct cdns_i3c_master *master,
+					unsigned int slot,
+					struct i2c_dev_boardinfo *info)
+{
+	u32 rr;
+
+	memset(info, 0, sizeof(*info));
+	rr = readl(master->regs + DEV_ID_RR0(slot));
+	info->base.addr = DEV_ID_RR0_GET_DEV_ADDR(rr);
+	rr = readl(master->regs + DEV_ID_RR2(slot));
+	info->lvr = rr;
+}
+
+static
+int cdns_i3c_sec_master_request_mastership(struct i3c_master_controller *m)
+{
+	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
+	u32 status;
+	int ret;
+
+	status = readl(master->regs + MST_STATUS0);
+	if (status & MST_STATUS0_MASTER_MODE)
+		return -EEXIST;
+
+	status = readl(master->regs + SLV_STATUS1);
+	if (status & SLV_STATUS1_MR_DIS)
+		return -EBUSY;
+
+	writel(readl(master->regs + CTRL) | CTRL_MST_INIT | CTRL_MST_ACK,
+	       master->regs + CTRL);
+
+	writel(SLV_INT_MR_DONE, master->regs + SLV_IER);
+
+	ret = readl_poll_timeout(master->regs + MST_STATUS0, status,
+				 status & MST_STATUS0_MASTER_MODE, 100,
+				 1000000);
+
+	return ret;
+}
+
+static void cdns_i3c_master_update_devs(struct i3c_master_controller *m)
+{
+	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
+	u32 val, newdevs;
+	int slot;
+	struct i3c_device_info i3c_info;
+	struct i2c_dev_boardinfo i2c_info;
+
+	newdevs = readl(master->regs + DEVS_CTRL) & DEVS_CTRL_DEVS_ACTIVE_MASK;
+	for (slot = 1; slot <= master->maxdevs; slot++) {
+		val = readl(master->regs + DEV_ID_RR0(slot));
+
+		if ((newdevs & BIT(slot)) && (val & DEV_ID_RR0_IS_I3C)) {
+			cdns_i3c_master_i3c_dev_rr_to_info(master, slot,
+							   &i3c_info);
+			i3c_master_add_i3c_dev_locked(m, i3c_info.dyn_addr);
+		} else if ((newdevs & BIT(slot)) &&
+			   !(val & DEV_ID_RR0_IS_I3C)) {
+			cdns_i3c_master_i2c_dev_rr_to_boardinfo(master, slot,
+								&i2c_info);
+			i3c_master_add_i2c_dev(m, &i2c_info);
+		}
+	}
+}
+
 static enum i3c_error_code cdns_i3c_cmd_get_err(struct cdns_i3c_cmd *cmd)
 {
 	switch (cmd->error) {
@@ -945,6 +1033,8 @@ static int cdns_i3c_master_reattach_i3c_dev(struct i3c_dev_desc *dev,
 	return 0;
 }
 
+static int cdns_i3c_master_enable_mastership(struct i3c_dev_desc *dev);
+
 static int cdns_i3c_master_attach_i3c_dev(struct i3c_dev_desc *dev)
 {
 	struct i3c_master_controller *m = i3c_dev_get_master(dev);
@@ -1045,22 +1135,6 @@ static void cdns_i3c_master_bus_cleanup(struct i3c_master_controller *m)
 	cdns_i3c_master_disable(master);
 }
 
-static void cdns_i3c_master_dev_rr_to_info(struct cdns_i3c_master *master,
-					   unsigned int slot,
-					   struct i3c_device_info *info)
-{
-	u32 rr;
-
-	memset(info, 0, sizeof(*info));
-	rr = readl(master->regs + DEV_ID_RR0(slot));
-	info->dyn_addr = DEV_ID_RR0_GET_DEV_ADDR(rr);
-	rr = readl(master->regs + DEV_ID_RR2(slot));
-	info->dcr = rr;
-	info->bcr = rr >> 8;
-	info->pid = rr >> 16;
-	info->pid |= (u64)readl(master->regs + DEV_ID_RR1(slot)) << 16;
-}
-
 static void cdns_i3c_master_upd_i3c_scl_lim(struct cdns_i3c_master *master)
 {
 	struct i3c_master_controller *m = &master->base;
@@ -1259,15 +1333,17 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
 	prescl1 = PRESCL_CTRL1_OD_LOW(ncycles);
 	writel(prescl1, master->regs + PRESCL_CTRL1);
 
-	/* Get an address for the master. */
-	ret = i3c_master_get_free_addr(m, 0);
-	if (ret < 0)
-		return ret;
+	if (!m->secondary) {
+		/* Get an address for the master. */
+		ret = i3c_master_get_free_addr(m, 0);
+		if (ret < 0)
+			return ret;
 
-	writel(prepare_rr0_dev_address(ret) | DEV_ID_RR0_IS_I3C,
-	       master->regs + DEV_ID_RR0(0));
+		writel(prepare_rr0_dev_address(ret) | DEV_ID_RR0_IS_I3C,
+		       master->regs + DEV_ID_RR0(0));
+	}
 
-	cdns_i3c_master_dev_rr_to_info(master, 0, &info);
+	cdns_i3c_master_i3c_dev_rr_to_info(master, 0, &info);
 	if (info.bcr & I3C_BCR_HDR_CAP)
 		info.hdr_cap = I3C_CCC_HDR_MODE(I3C_HDR_DDR);
 
@@ -1289,6 +1365,23 @@ static int cdns_i3c_master_bus_init(struct i3c_master_controller *m)
 	return 0;
 }
 
+static
+struct i3c_dev_desc *cdns_i3c_get_ibi_device(struct cdns_i3c_master *master,
+					     u32 ibir)
+{
+	struct i3c_dev_desc *dev;
+	u32 id = IBIR_SLVID(ibir);
+
+	if (id >= master->ibi.num_slots || (ibir & IBIR_ERROR))
+		return NULL;
+
+	dev = master->ibi.slots[id];
+	if (!dev)
+		return NULL;
+
+	return dev;
+}
+
 static void cdns_i3c_master_handle_ibi(struct cdns_i3c_master *master,
 				       u32 ibir)
 {
@@ -1366,27 +1459,79 @@ static void cnds_i3c_master_demux_ibis(struct cdns_i3c_master *master)
 
 		case IBIR_TYPE_MR:
 			WARN_ON(IBIR_XFER_BYTES(ibir) || (ibir & IBIR_ERROR));
+			master->mastership.ibir = ibir;
+			queue_work(master->base.wq,
+				   &master->mastership.handover_work);
+			break;
 		default:
 			break;
 		}
 	}
 }
 
+static void cdns_i3c_master_bus_handoff(struct cdns_i3c_master *master)
+{
+	struct i3c_dev_desc *dev;
+
+	dev = cdns_i3c_get_ibi_device(master, master->mastership.ibir);
+
+	writel(MST_INT_MR_DONE, master->regs + MST_ICR);
+	i3c_master_switch_operation_mode(&master->base, dev, I3C_SLAVE_MODE);
+}
+
+static void cdns_i3c_sec_master_takeover(struct cdns_i3c_master *master)
+{
+	writel(SLV_INT_MR_DONE, master->regs + SLV_ICR);
+	i3c_master_switch_operation_mode(&master->base,
+					 master->base.this, I3C_MASTER_MODE);
+}
+
+static void cdns_i3c_sec_master_event_up(struct cdns_i3c_master *master)
+{
+	u32 status;
+	u8 evts = 0;
+
+	writel(SLV_INT_EVENT_UP, master->regs + SLV_ICR);
+	status = readl(master->regs + SLV_STATUS1);
+	if (!(status & SLV_STATUS1_MR_DIS))
+		evts |= I3C_CCC_EVENT_MR;
+	if (!(status & SLV_STATUS1_HJ_DIS))
+		evts |= I3C_CCC_EVENT_HJ;
+
+	i3c_secondary_master_events_enabled(&master->base, evts);
+}
+
 static irqreturn_t cdns_i3c_master_interrupt(int irq, void *data)
 {
 	struct cdns_i3c_master *master = data;
 	u32 status;
 
-	status = readl(master->regs + MST_ISR);
-	if (!(status & readl(master->regs + MST_IMR)))
-		return IRQ_NONE;
+	if (master->base.op_mode == I3C_SLAVE_MODE) {
+		status = readl(master->regs + SLV_ISR);
 
-	spin_lock(&master->xferqueue.lock);
-	cdns_i3c_master_end_xfer_locked(master, status);
-	spin_unlock(&master->xferqueue.lock);
+		if (!(status & readl(master->regs + SLV_IMR)))
+			return IRQ_NONE;
 
-	if (status & MST_INT_IBIR_THR)
-		cnds_i3c_master_demux_ibis(master);
+		if (status & SLV_INT_MR_DONE)
+			cdns_i3c_sec_master_takeover(master);
+
+		if (status & SLV_INT_EVENT_UP)
+			cdns_i3c_sec_master_event_up(master);
+	} else {
+		status = readl(master->regs + MST_ISR);
+		if (!(status & readl(master->regs + MST_IMR)))
+			return IRQ_NONE;
+
+		spin_lock(&master->xferqueue.lock);
+		cdns_i3c_master_end_xfer_locked(master, status);
+		spin_unlock(&master->xferqueue.lock);
+
+		if (status & MST_INT_IBIR_THR)
+			cnds_i3c_master_demux_ibis(master);
+
+		if (status & MST_INT_MR_DONE)
+			cdns_i3c_master_bus_handoff(master);
+	}
 
 	return IRQ_HANDLED;
 }
@@ -1455,30 +1600,46 @@ static int cdns_i3c_master_enable_ibi(struct i3c_dev_desc *dev)
 	return ret;
 }
 
-static int cdns_i3c_master_request_ibi(struct i3c_dev_desc *dev,
-				       const struct i3c_ibi_setup *req)
+static int cdns_i3c_master_find_ibi_slot(struct cdns_i3c_master *master,
+					 struct i3c_dev_desc *dev,
+					 s16 *slot)
 {
-	struct i3c_master_controller *m = i3c_dev_get_master(dev);
-	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
-	struct cdns_i3c_i2c_dev_data *data = i3c_dev_get_master_data(dev);
 	unsigned long flags;
 	unsigned int i;
-
-	data->ibi_pool = i3c_generic_ibi_alloc_pool(dev, req);
-	if (IS_ERR(data->ibi_pool))
-		return PTR_ERR(data->ibi_pool);
+	int ret = -ENOENT;
 
 	spin_lock_irqsave(&master->ibi.lock, flags);
 	for (i = 0; i < master->ibi.num_slots; i++) {
-		if (!master->ibi.slots[i]) {
-			data->ibi = i;
+		/*
+		 * We only need 'SIR' slots to describe IBI-capable devices.
+		 * This slot may be used by mastership request interrupt,
+		 * We can ruse the same 'SIR' map entry.
+		 */
+		if (!master->ibi.slots[i] ||
+		    master->ibi.slots[i] == dev) {
 			master->ibi.slots[i] = dev;
+			*slot = i;
+			ret = 0;
 			break;
 		}
 	}
 	spin_unlock_irqrestore(&master->ibi.lock, flags);
 
-	if (i < master->ibi.num_slots)
+	return ret;
+}
+
+static int cdns_i3c_master_request_ibi(struct i3c_dev_desc *dev,
+				       const struct i3c_ibi_setup *req)
+{
+	struct i3c_master_controller *m = i3c_dev_get_master(dev);
+	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
+	struct cdns_i3c_i2c_dev_data *data = i3c_dev_get_master_data(dev);
+
+	data->ibi_pool = i3c_generic_ibi_alloc_pool(dev, req);
+	if (IS_ERR(data->ibi_pool))
+		return PTR_ERR(data->ibi_pool);
+
+	if (cdns_i3c_master_find_ibi_slot(master, dev, &data->ibi) == 0)
 		return 0;
 
 	i3c_generic_ibi_free_pool(data->ibi_pool);
@@ -1487,6 +1648,37 @@ static int cdns_i3c_master_request_ibi(struct i3c_dev_desc *dev,
 	return -ENOSPC;
 }
 
+static int cdns_i3c_master_enable_mastership(struct i3c_dev_desc *dev)
+{
+	struct i3c_master_controller *m = i3c_dev_get_master(dev);
+	struct cdns_i3c_master *master = to_cdns_i3c_master(m);
+	struct cdns_i3c_i2c_dev_data *data = i3c_dev_get_master_data(dev);
+	unsigned long flags;
+	u32 sircfg, sirmap;
+	int ret;
+
+	ret = cdns_i3c_master_find_ibi_slot(master, dev, &data->ibi);
+	if (ret)
+		return -ENOSPC;
+
+	spin_lock_irqsave(&master->ibi.lock, flags);
+	sirmap = readl(master->regs + SIR_MAP_DEV_REG(data->ibi));
+	sirmap &= ~SIR_MAP_DEV_CONF_MASK(data->ibi);
+	sircfg = SIR_MAP_DEV_ROLE(dev->info.bcr >> 6) |
+		 SIR_MAP_DEV_DA(dev->info.dyn_addr) |
+		 SIR_MAP_DEV_PL(dev->info.max_ibi_len) |
+		 SIR_MAP_DEV_ACK;
+
+	if (dev->info.bcr & I3C_BCR_MAX_DATA_SPEED_LIM)
+		sircfg |= SIR_MAP_DEV_SLOW;
+
+	sirmap |= SIR_MAP_DEV_CONF(data->ibi, sircfg);
+	writel(sirmap, master->regs + SIR_MAP_DEV_REG(data->ibi));
+	spin_unlock_irqrestore(&master->ibi.lock, flags);
+
+	return 0;
+}
+
 static void cdns_i3c_master_free_ibi(struct i3c_dev_desc *dev)
 {
 	struct i3c_master_controller *m = i3c_dev_get_master(dev);
@@ -1529,6 +1721,9 @@ static const struct i3c_master_controller_ops cdns_i3c_master_ops = {
 	.request_ibi = cdns_i3c_master_request_ibi,
 	.free_ibi = cdns_i3c_master_free_ibi,
 	.recycle_ibi_slot = cdns_i3c_master_recycle_ibi_slot,
+	.request_mastership = cdns_i3c_sec_master_request_mastership,
+	.update_devs = cdns_i3c_master_update_devs,
+	.enable_mastership = cdns_i3c_master_enable_mastership
 };
 
 static void cdns_i3c_master_hj(struct work_struct *work)
@@ -1537,13 +1732,31 @@ static void cdns_i3c_master_hj(struct work_struct *work)
 						      struct cdns_i3c_master,
 						      hj_work);
 
-	i3c_master_do_daa(&master->base);
+	if (!master->base.secondary)
+		i3c_master_do_daa(&master->base);
+}
+
+static void cdns_i3c_master_mastership_handover(struct work_struct *work)
+{
+	struct cdns_i3c_master *master = container_of(work,
+						      struct cdns_i3c_master,
+						      mastership.handover_work);
+	struct i3c_dev_desc *dev;
+	u32 ibir = master->mastership.ibir;
+
+	dev = cdns_i3c_get_ibi_device(master, ibir);
+	if (!dev)
+		return;
+
+	if (i3c_master_mastership_ack(&master->base, &dev->info))
+		dev_err(&master->base.dev, "Mastership handover failed\n");
 }
 
 static int cdns_i3c_master_probe(struct platform_device *pdev)
 {
 	struct cdns_i3c_master *master;
 	struct resource *res;
+	bool secondary = false;
 	int ret, irq;
 	u32 val;
 
@@ -1585,15 +1798,22 @@ static int cdns_i3c_master_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&master->xferqueue.list);
 
 	INIT_WORK(&master->hj_work, cdns_i3c_master_hj);
+	INIT_WORK(&master->mastership.handover_work,
+		  cdns_i3c_master_mastership_handover);
 	writel(0xffffffff, master->regs + MST_IDR);
 	writel(0xffffffff, master->regs + SLV_IDR);
 	ret = devm_request_irq(&pdev->dev, irq, cdns_i3c_master_interrupt, 0,
 			       dev_name(&pdev->dev), master);
+
 	if (ret)
 		goto err_disable_sysclk;
 
 	platform_set_drvdata(pdev, master);
 
+	val = readl(master->regs + MST_STATUS0);
+	if (!(val & MST_STATUS0_MASTER_MODE))
+		secondary = true;
+
 	val = readl(master->regs + CONF_STATUS0);
 
 	/* Device ID0 is reserved to describe this master. */
@@ -1609,6 +1829,7 @@ static int cdns_i3c_master_probe(struct platform_device *pdev)
 
 	spin_lock_init(&master->ibi.lock);
 	master->ibi.num_slots = CONF_STATUS1_IBI_HW_RES(val);
+
 	master->ibi.slots = devm_kcalloc(&pdev->dev, master->ibi.num_slots,
 					 sizeof(*master->ibi.slots),
 					 GFP_KERNEL);
@@ -1620,10 +1841,14 @@ static int cdns_i3c_master_probe(struct platform_device *pdev)
 	writel(DEVS_CTRL_DEV_CLR_ALL, master->regs + DEVS_CTRL);
 
 	ret = i3c_master_register(&master->base, &pdev->dev,
-				  &cdns_i3c_master_ops, false);
+				  &cdns_i3c_master_ops, secondary);
 	if (ret)
 		goto err_disable_sysclk;
 
+	if (secondary)
+		writel(SLV_INT_EVENT_UP,
+		       master->regs + SLV_IER);
+
 	return 0;
 
 err_disable_sysclk:
@@ -1666,6 +1891,7 @@ static struct platform_driver cdns_i3c_master = {
 module_platform_driver(cdns_i3c_master);
 
 MODULE_AUTHOR("Boris Brezillon <boris.brezillon@bootlin.com>");
+MODULE_AUTHOR("Przemyslaw Gaj <pgaj@cadence.com>");
 MODULE_DESCRIPTION("Cadence I3C master driver");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:cdns-i3c-master");
-- 
2.4.5


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