From: Adrian Hunter Date: Mon, 8 Jun 2026 05:43:12 +0000 (+0300) Subject: i3c: mipi-i3c-hci: Add Hot-Join support X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=32fcf0039814d886f51fc37522c94da91759a4cc;p=thirdparty%2Flinux.git i3c: mipi-i3c-hci: Add Hot-Join support Wire the MIPI I3C HCI driver into the I3C core Hot-Join framework to allow targets to dynamically join the bus after initial DAA. HCI hardware ACKs or NACKs Hot-Join requests based on HC_CONTROL.HOT_JOIN_CTRL. This was previously left in the NACK-and-DISEC state, effectively preventing Hot-Join. Implement the ->enable_hotjoin() and ->disable_hotjoin() master operations so the core and user space can control this policy at runtime. Also issue broadcast ENEC HJ when enabling Hot-Join. This is required because the controller may have previously DISEC'ed the Hot-Join event, causing targets that were NACKed once to never retry. Acknowledged Hot-Join requests are delivered as IBIs on the reserved address 0x02. Update both the DMA and PIO IBI paths to recognise this address and forward the event to i3c_master_queue_hotjoin(). To make Hot-Join usable by default, enable it once after the initial DAA. This is gated by rpm_ibi_allowed, since otherwise keeping Hot-Join enabled prevents runtime suspend. A new hj_init_done flag ensures this one-time enablement is not repeated on subsequent DAAs. Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260608054312.10604-9-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni --- diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c index c6edbbedfdd7f..53797841b63f9 100644 --- a/drivers/i3c/master/mipi-i3c-hci/core.c +++ b/drivers/i3c/master/mipi-i3c-hci/core.c @@ -392,11 +392,52 @@ out: return ret; } +static int i3c_hci_enable_hotjoin(struct i3c_master_controller *m) +{ + struct i3c_hci *hci = to_i3c_hci(m); + int ret; + + reg_clear(HC_CONTROL, HC_CONTROL_HOT_JOIN_CTRL); + + /* + * Broadcast Hot_join enable, so that an I3C device that has previously + * had its Hot-Join request NACK'ed knows to try again. + */ + ret = i3c_master_enec_disec_locked(m, I3C_BROADCAST_ADDR, true, I3C_CCC_EVENT_HJ, true); + if (ret) { + reg_set(HC_CONTROL, HC_CONTROL_HOT_JOIN_CTRL); + dev_err(&hci->master.dev, "Hot-Join ENEC CCC failed\n"); + } + + return ret; +} + +static int i3c_hci_disable_hotjoin(struct i3c_master_controller *m) +{ + struct i3c_hci *hci = to_i3c_hci(m); + + reg_set(HC_CONTROL, HC_CONTROL_HOT_JOIN_CTRL); + return 0; +} + static int i3c_hci_daa(struct i3c_master_controller *m) { struct i3c_hci *hci = to_i3c_hci(m); + int ret; - return hci->cmd->perform_daa(hci); + ret = hci->cmd->perform_daa(hci); + + if (!hci->hj_init_done) { + hci->hj_init_done = true; + /* + * Enable Hot-Join by default after initial DAA if it does not + * prevent runtime suspend. + */ + if (m->rpm_ibi_allowed && !ret) + m->hotjoin = !i3c_hci_enable_hotjoin(m); + } + + return ret; } static int i3c_hci_i3c_xfers(struct i3c_dev_desc *dev, @@ -652,6 +693,8 @@ static const struct i3c_master_controller_ops i3c_hci_ops = { .enable_ibi = i3c_hci_enable_ibi, .disable_ibi = i3c_hci_disable_ibi, .recycle_ibi_slot = i3c_hci_recycle_ibi_slot, + .enable_hotjoin = i3c_hci_enable_hotjoin, + .disable_hotjoin = i3c_hci_disable_hotjoin, }; static irqreturn_t i3c_hci_irq_handler(int irq, void *dev_id) @@ -833,8 +876,9 @@ static int i3c_hci_do_reset_and_restore(struct i3c_hci *hci) scoped_guard(spinlock_irqsave, &hci->lock) hci->irq_inactive = false; - /* Enable bus with Hot-Join disabled */ - reg_set(HC_CONTROL, HC_CONTROL_BUS_ENABLE | HC_CONTROL_HOT_JOIN_CTRL); + /* Enable bus, restoring hot-join state */ + reg_set(HC_CONTROL, + HC_CONTROL_BUS_ENABLE | (hci->master.hotjoin ? 0 : HC_CONTROL_HOT_JOIN_CTRL)); return 0; } diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c index 5c6ae20556184..87622d6f817e8 100644 --- a/drivers/i3c/master/mipi-i3c-hci/dma.c +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c @@ -960,6 +960,11 @@ static void hci_dma_process_ibi(struct i3c_hci *hci, struct hci_rh_data *rh) } /* determine who this is for */ + if (ibi_addr == I3C_HOT_JOIN_ADDR) { + i3c_master_queue_hotjoin(&hci->master); + goto done; + } + dev = i3c_hci_addr_to_dev(hci, ibi_addr); if (!dev) { dev_err(&hci->master.dev, diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h index 30297823ca855..41d31a53abd37 100644 --- a/drivers/i3c/master/mipi-i3c-hci/hci.h +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h @@ -57,6 +57,7 @@ struct i3c_hci { bool irq_inactive; bool enqueue_blocked; bool recovery_needed; + bool hj_init_done; wait_queue_head_t enqueue_wait_queue; u32 caps; unsigned int quirks; diff --git a/drivers/i3c/master/mipi-i3c-hci/pio.c b/drivers/i3c/master/mipi-i3c-hci/pio.c index 6b8cc5f2b4d2e..b5ae1cfaa9e03 100644 --- a/drivers/i3c/master/mipi-i3c-hci/pio.c +++ b/drivers/i3c/master/mipi-i3c-hci/pio.c @@ -862,6 +862,11 @@ static bool hci_pio_prep_new_ibi(struct i3c_hci *hci, struct hci_pio_data *pio) ibi->seg_len = FIELD_GET(IBI_DATA_LENGTH, ibi_status); ibi->seg_cnt = ibi->seg_len; + if (ibi->addr == I3C_HOT_JOIN_ADDR) { + i3c_master_queue_hotjoin(&hci->master); + return true; + } + dev = i3c_hci_addr_to_dev(hci, ibi->addr); if (!dev) { dev_err(&hci->master.dev,