1 files changed, 231 insertions, 24 deletions

diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index a44d4b3e5beb..ff292b9e0be9 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -91,6 +91,14 @@ struct pcc_chan_reg {
  * @cmd_update: PCC register bundle for the command complete update register
  * @error: PCC register bundle for the error status register
  * @plat_irq: platform interrupt
+ * @type: PCC subspace type
+ * @plat_irq_flags: platform interrupt flags
+ * @chan_in_use: this flag is used just to check if the interrupt needs
+ *		handling when it is shared. Since only one transfer can occur
+ *		at a time and mailbox takes care of locking, this flag can be
+ *		accessed without a lock. Note: the type only support the
+ *		communication from OSPM to Platform, like type3, use it, and
+ *		other types completely ignore it.
  */
 struct pcc_chan_info {
 	struct pcc_mbox_chan chan;
@@ -100,6 +108,9 @@ struct pcc_chan_info {
 	struct pcc_chan_reg cmd_update;
 	struct pcc_chan_reg error;
 	int plat_irq;
+	u8 type;
+	unsigned int plat_irq_flags;
+	bool chan_in_use;
 };
 
 #define to_pcc_chan_info(c) container_of(c, struct pcc_chan_info, chan)
@@ -221,6 +232,95 @@ static int pcc_map_interrupt(u32 interrupt, u32 flags)
 	return acpi_register_gsi(NULL, interrupt, trigger, polarity);
 }
 
+static bool pcc_chan_plat_irq_can_be_shared(struct pcc_chan_info *pchan)
+{
+	return (pchan->plat_irq_flags & ACPI_PCCT_INTERRUPT_MODE) ==
+		ACPI_LEVEL_SENSITIVE;
+}
+
+static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
+{
+	u64 val;
+	int ret;
+
+	if (!pchan->cmd_complete.gas)
+		return true;
+
+	ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
+	if (ret)
+		return false;
+
+	/*
+	 * Judge if the channel respond the interrupt based on the value of
+	 * command complete.
+	 */
+	val &= pchan->cmd_complete.status_mask;
+
+	/*
+	 * If this is PCC slave subspace channel, and the command complete
+	 * bit 0 indicates that Platform is sending a notification and OSPM
+	 * needs to respond this interrupt to process this command.
+	 */
+	if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
+		return !val;
+
+	return !!val;
+}
+
+static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan)
+{
+	u64 val;
+	int ret;
+
+	ret = pcc_chan_reg_read(&pchan->error, &val);
+	if (ret)
+		return ret;
+
+	if (val & pchan->error.status_mask) {
+		val &= pchan->error.preserve_mask;
+		pcc_chan_reg_write(&pchan->error, val);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void pcc_chan_acknowledge(struct pcc_chan_info *pchan)
+{
+	struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_hdr;
+
+	if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
+		return;
+
+	pcc_chan_reg_read_modify_write(&pchan->cmd_update);
+
+	pcc_hdr = pchan->chan.shmem;
+
+	/*
+	 * The PCC slave subspace channel needs to set the command
+	 * complete bit after processing message. If the PCC_ACK_FLAG
+	 * is set, it should also ring the doorbell.
+	 */
+	if (ioread32(&pcc_hdr->flags) & PCC_CMD_COMPLETION_NOTIFY)
+		pcc_chan_reg_read_modify_write(&pchan->db);
+}
+
+static void *write_response(struct pcc_chan_info *pchan)
+{
+	struct pcc_header pcc_header;
+	void *buffer;
+	int data_len;
+
+	memcpy_fromio(&pcc_header, pchan->chan.shmem,
+		      sizeof(pcc_header));
+	data_len = pcc_header.length - sizeof(u32) + sizeof(struct pcc_header);
+
+	buffer = pchan->chan.rx_alloc(pchan->chan.mchan->cl, data_len);
+	if (buffer != NULL)
+		memcpy_fromio(buffer, pchan->chan.shmem, data_len);
+	return buffer;
+}
+
 /**
  * pcc_mbox_irq - PCC mailbox interrupt handler
  * @irq:	interrupt number
@@ -232,35 +332,44 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
 {
 	struct pcc_chan_info *pchan;
 	struct mbox_chan *chan = p;
-	u64 val;
-	int ret;
+	struct pcc_header *pcc_header = chan->active_req;
+	void *handle = NULL;
 
 	pchan = chan->con_priv;
 
-	ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
-	if (ret)
+	if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
 		return IRQ_NONE;
 
-	if (val) { /* Ensure GAS exists and value is non-zero */
-		val &= pchan->cmd_complete.status_mask;
-		if (!val)
-			return IRQ_NONE;
-	}
+	if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_MASTER_SUBSPACE &&
+	    !pchan->chan_in_use)
+		return IRQ_NONE;
 
-	ret = pcc_chan_reg_read(&pchan->error, &val);
-	if (ret)
+	if (!pcc_mbox_cmd_complete_check(pchan))
 		return IRQ_NONE;
-	val &= pchan->error.status_mask;
-	if (val) {
-		val &= ~pchan->error.status_mask;
-		pcc_chan_reg_write(&pchan->error, val);
+
+	if (pcc_mbox_error_check_and_clear(pchan))
 		return IRQ_NONE;
+
+	/*
+	 * Clear this flag after updating interrupt ack register and just
+	 * before mbox_chan_received_data() which might call pcc_send_data()
+	 * where the flag is set again to start new transfer. This is
+	 * required to avoid any possible race in updatation of this flag.
+	 */
+	pchan->chan_in_use = false;
+
+	if (pchan->chan.rx_alloc)
+		handle = write_response(pchan);
+
+	if (chan->active_req) {
+		pcc_header = chan->active_req;
+		if (pcc_header->flags & PCC_CMD_COMPLETION_NOTIFY)
+			mbox_chan_txdone(chan, 0);
 	}
 
-	if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
-		return IRQ_NONE;
+	mbox_chan_received_data(chan, handle);
 
-	mbox_chan_received_data(chan, NULL);
+	pcc_chan_acknowledge(pchan);
 
 	return IRQ_HANDLED;
 }
@@ -280,6 +389,7 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
 struct pcc_mbox_chan *
 pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
 {
+	struct pcc_mbox_chan *pcc_mchan;
 	struct pcc_chan_info *pchan;
 	struct mbox_chan *chan;
 	int rc;
@@ -298,7 +408,29 @@ pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
 	if (rc)
 		return ERR_PTR(rc);
 
-	return &pchan->chan;
+	pcc_mchan = &pchan->chan;
+	pcc_mchan->shmem = acpi_os_ioremap(pcc_mchan->shmem_base_addr,
+					   pcc_mchan->shmem_size);
+	if (!pcc_mchan->shmem)
+		goto err;
+
+	pcc_mchan->manage_writes = false;
+
+	/* This indicates that the channel is ready to accept messages.
+	 * This needs to happen after the channel has registered
+	 * its callback. There is no access point to do that in
+	 * the mailbox API. That implies that the mailbox client must
+	 * have set the allocate callback function prior to
+	 * sending any messages.
+	 */
+	if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
+		pcc_chan_reg_read_modify_write(&pchan->cmd_update);
+
+	return pcc_mchan;
+
+err:
+	mbox_free_channel(chan);
+	return ERR_PTR(-ENXIO);
 }
 EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
 
@@ -311,16 +443,54 @@ EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
 void pcc_mbox_free_channel(struct pcc_mbox_chan *pchan)
 {
 	struct mbox_chan *chan = pchan->mchan;
+	struct pcc_chan_info *pchan_info;
+	struct pcc_mbox_chan *pcc_mbox_chan;
 
 	if (!chan || !chan->cl)
 		return;
+	pchan_info = chan->con_priv;
+	pcc_mbox_chan = &pchan_info->chan;
+	if (pcc_mbox_chan->shmem) {
+		iounmap(pcc_mbox_chan->shmem);
+		pcc_mbox_chan->shmem = NULL;
+	}
 
 	mbox_free_channel(chan);
 }
 EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
 
+static int pcc_write_to_buffer(struct mbox_chan *chan, void *data)
+{
+	struct pcc_chan_info *pchan = chan->con_priv;
+	struct pcc_mbox_chan *pcc_mbox_chan = &pchan->chan;
+	struct pcc_header *pcc_header = data;
+
+	if (!pchan->chan.manage_writes)
+		return 0;
+
+	/* The PCC header length includes the command field
+	 * but not the other values from the header.
+	 */
+	int len = pcc_header->length - sizeof(u32) + sizeof(struct pcc_header);
+	u64 val;
+
+	pcc_chan_reg_read(&pchan->cmd_complete, &val);
+	if (!val) {
+		pr_info("%s pchan->cmd_complete not set", __func__);
+		return -1;
+	}
+	memcpy_toio(pcc_mbox_chan->shmem,  data, len);
+	return 0;
+}
+
+
 /**
- * pcc_send_data - Called from Mailbox Controller code. Used
+ * pcc_send_data - Called from Mailbox Controller code. If
+ *		pchan->chan.rx_alloc is set, then the command complete
+ *		flag is checked and the data is written to the shared
+ *		buffer io memory.
+ *
+ *		If pchan->chan.rx_alloc is not set, then it is used
  *		here only to ring the channel doorbell. The PCC client
  *		specific read/write is done in the client driver in
  *		order to maintain atomicity over PCC channel once
@@ -336,13 +506,37 @@ static int pcc_send_data(struct mbox_chan *chan, void *data)
 	int ret;
 	struct pcc_chan_info *pchan = chan->con_priv;
 
+	ret = pcc_write_to_buffer(chan, data);
+	if (ret)
+		return ret;
+
 	ret = pcc_chan_reg_read_modify_write(&pchan->cmd_update);
 	if (ret)
 		return ret;
 
-	return pcc_chan_reg_read_modify_write(&pchan->db);
+	ret = pcc_chan_reg_read_modify_write(&pchan->db);
+
+	if (!ret && pchan->plat_irq > 0)
+		pchan->chan_in_use = true;
+
+	return ret;
+}
+
+
+static bool pcc_last_tx_done(struct mbox_chan *chan)
+{
+	struct pcc_chan_info *pchan = chan->con_priv;
+	u64 val;
+
+	pcc_chan_reg_read(&pchan->cmd_complete, &val);
+	if (!val)
+		return false;
+	else
+		return true;
 }
 
+
+
 /**
  * pcc_startup - Called from Mailbox Controller code. Used here
  *		to request the interrupt.
@@ -353,11 +547,14 @@ static int pcc_send_data(struct mbox_chan *chan, void *data)
 static int pcc_startup(struct mbox_chan *chan)
 {
 	struct pcc_chan_info *pchan = chan->con_priv;
+	unsigned long irqflags;
 	int rc;
 
 	if (pchan->plat_irq > 0) {
-		rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq, 0,
-				      MBOX_IRQ_NAME, chan);
+		irqflags = pcc_chan_plat_irq_can_be_shared(pchan) ?
+						IRQF_SHARED | IRQF_ONESHOT : 0;
+		rc = devm_request_irq(chan->mbox->dev, pchan->plat_irq, pcc_mbox_irq,
+				      irqflags, MBOX_IRQ_NAME, chan);
 		if (unlikely(rc)) {
 			dev_err(chan->mbox->dev, "failed to register PCC interrupt %d\n",
 				pchan->plat_irq);
@@ -385,6 +582,7 @@ static const struct mbox_chan_ops pcc_chan_ops = {
 	.send_data = pcc_send_data,
 	.startup = pcc_startup,
 	.shutdown = pcc_shutdown,
+	.last_tx_done = pcc_last_tx_done,
 };
 
 /**
@@ -463,6 +661,7 @@ static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
 		       pcct_ss->platform_interrupt);
 		return -EINVAL;
 	}
+	pchan->plat_irq_flags = pcct_ss->flags;
 
 	if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
 		struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
@@ -484,6 +683,12 @@ static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
 					"PLAT IRQ ACK");
 	}
 
+	if (pcc_chan_plat_irq_can_be_shared(pchan) &&
+	    !pchan->plat_irq_ack.gas) {
+		pr_err("PCC subspace has level IRQ with no ACK register\n");
+		return -EINVAL;
+	}
+
 	return ret;
 }
 
@@ -539,7 +744,8 @@ static int pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
 
 		ret = pcc_chan_reg_init(&pchan->error,
 					&pcct_ext->error_status_register,
-					0, 0, pcct_ext->error_status_mask,
+					~pcct_ext->error_status_mask, 0,
+					pcct_ext->error_status_mask,
 					"Error Status");
 	}
 	return ret;
@@ -698,6 +904,7 @@ static int pcc_mbox_probe(struct platform_device *pdev)
 
 		pcc_parse_subspace_shmem(pchan, pcct_entry);
 
+		pchan->type = pcct_entry->type;
 		pcct_entry = (struct acpi_subtable_header *)
 			((unsigned long) pcct_entry + pcct_entry->length);
 	}