linux-kernel - [PATCH v2 06/14] mailbox: pcc: Add pcc_mbox_chan structure to hold shared memory region info

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Date:   Fri, 17 Sep 2021 14:33:49 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Cristian Marussi <cristian.marussi@....com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Jassi Brar <jassisinghbrar@...il.com>
Subject: [PATCH v2 06/14] mailbox: pcc: Add pcc_mbox_chan structure to hold shared memory region info

Currently PCC mailbox controller sets con_priv in each channel to hold
the pointer to pcct subspace entry it corresponds to. The mailbox user
will then fetch this pointer from the channel descriptor they get when
they request for the channel. Using that pointer they then parse the
pcct entry again to fetch all the information about shared memory region.

In order to remove individual users of PCC mailbox parsing the PCCT
subspace entries to fetch same information, let us consolidate the same
in pcc mailbox controller by parsing all the shared memory region
information into a structure that can also hold the mbox_chan pointer it
represent.

This can then be used as main PCC mailbox channel pointer that we can
return as part of pcc_mbox_request_channel instead of standard mailbox
channel pointer.

Reviewed-by: Cristian Marussi <cristian.marussi@....com>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/mailbox/pcc.c | 27 +++++++++++++++++++++++++++
 include/acpi/pcc.h    |  9 +++++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 97c44c431ada..f358ced827f2 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -67,11 +67,13 @@ static struct mbox_chan *pcc_mbox_channels;
 /**
  * struct pcc_chan_info - PCC channel specific information
  *
+ * @chan: PCC channel information with Shared Memory Region info
  * @db_vaddr: cached virtual address for doorbell register
  * @db_ack_vaddr: cached virtual address for doorbell ack register
  * @db_irq: doorbell interrupt
  */
 struct pcc_chan_info {
+	struct pcc_mbox_chan chan;
 	void __iomem *db_vaddr;
 	void __iomem *db_ack_vaddr;
 	int db_irq;
@@ -470,6 +472,27 @@ static void pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
 						  db_reg->bit_width / 8);
 }
 
+/**
+ * pcc_parse_subspace_shmem - Parse the PCC Shared Memory Region information
+ *
+ * @pchan: Pointer to the PCC channel info structure.
+ * @pcct_entry: Pointer to the ACPI subtable header.
+ *
+ */
+static void pcc_parse_subspace_shmem(struct pcc_chan_info *pchan,
+				     struct acpi_subtable_header *pcct_entry)
+{
+	struct acpi_pcct_subspace *pcct_ss;
+
+	pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
+
+	pchan->chan.shmem_base_addr = pcct_ss->base_address;
+	pchan->chan.shmem_size = pcct_ss->length;
+	pchan->chan.latency = pcct_ss->latency;
+	pchan->chan.max_access_rate = pcct_ss->max_access_rate;
+	pchan->chan.min_turnaround_time = pcct_ss->min_turnaround_time;
+}
+
 /**
  * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
  *
@@ -537,6 +560,8 @@ static int __init acpi_pcc_probe(void)
 		struct pcc_chan_info *pchan = chan_info + i;
 		pcc_mbox_channels[i].con_priv = pcct_entry;
 
+		pchan->chan.mchan = &pcc_mbox_channels[i];
+
 		if (pcc_mbox_ctrl.txdone_irq) {
 			rc = pcc_parse_subspace_irq(pchan, pcct_entry);
 			if (rc < 0)
@@ -544,6 +569,8 @@ static int __init acpi_pcc_probe(void)
 		}
 		pcc_parse_subspace_db_reg(pchan, pcct_entry);
 
+		pcc_parse_subspace_shmem(pchan, pcct_entry);
+
 		pcct_entry = (struct acpi_subtable_header *)
 			((unsigned long) pcct_entry + pcct_entry->length);
 	}
diff --git a/include/acpi/pcc.h b/include/acpi/pcc.h
index 4dec4ed138cd..5e510a6b8052 100644
--- a/include/acpi/pcc.h
+++ b/include/acpi/pcc.h
@@ -9,6 +9,15 @@
 #include <linux/mailbox_controller.h>
 #include <linux/mailbox_client.h>
 
+struct pcc_mbox_chan {
+	struct mbox_chan *mchan;
+	u64 shmem_base_addr;
+	u64 shmem_size;
+	u32 latency;
+	u32 max_access_rate;
+	u16 min_turnaround_time;
+};
+
 #define MAX_PCC_SUBSPACES	256
 #ifdef CONFIG_PCC
 extern struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
-- 
2.25.1