linux-kernel - [PATCH v2 12/13] ACPI: PCC: Simplify PCC shared memory region handling

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Message-Id: <20250305-pcc_fixes_updates-v2-12-1b1822bc8746@arm.com>
Date: Wed, 05 Mar 2025 16:38:16 +0000
From: Sudeep Holla <sudeep.holla@....com>
To: linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Sudeep Holla <sudeep.holla@....com>, 
 Jassi Brar <jassisinghbrar@...il.com>, Huisong Li <lihuisong@...wei.com>, 
 Adam Young <admiyo@...amperecomputing.com>, 
 Robbie King <robbiek@...ghtlabs.com>, 
 "Rafael J. Wysocki" <rafael@...nel.org>
Subject: [PATCH v2 12/13] ACPI: PCC: Simplify PCC shared memory region
 handling

The PCC driver now handles mapping and unmapping of shared memory
areas as part of pcc_mbox_{request,free}_channel(). Without these before,
this ACPI PCC opregion driver did handling of those mappings like several
other PCC mailbox client drivers.

There were redundant operations, leading to unnecessary code. Maintaining
the consistency across these driver was harder due to scattered handling
of shmem.

Just use the mapped shmem and remove all redundant operations from this
driver.

Cc: "Rafael J. Wysocki" <rafael@...nel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/acpi/acpi_pcc.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c
index 07a034a53acac1e8307265bcc5572054d34d971f..97064e943768ad9f1704effa13dddbc0876a9452 100644
--- a/drivers/acpi/acpi_pcc.c
+++ b/drivers/acpi/acpi_pcc.c
@@ -31,7 +31,6 @@

 struct pcc_data {
 	struct pcc_mbox_chan *pcc_chan;
-	void __iomem *pcc_comm_addr;
 	struct completion done;
 	struct mbox_client cl;
 	struct acpi_pcc_info ctx;
@@ -81,14 +80,6 @@ acpi_pcc_address_space_setup(acpi_handle region_handle, u32 function,
 		ret = AE_SUPPORT;
 		goto err_free_channel;
 	}
-	data->pcc_comm_addr = acpi_os_ioremap(pcc_chan->shmem_base_addr,
-					      pcc_chan->shmem_size);
-	if (!data->pcc_comm_addr) {
-		pr_err("Failed to ioremap PCC comm region mem for %d\n",
-		       ctx->subspace_id);
-		ret = AE_NO_MEMORY;
-		goto err_free_channel;
-	}

 	*region_context = data;
 	return AE_OK;
@@ -113,7 +104,7 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr,
 	reinit_completion(&data->done);

 	/* Write to Shared Memory */
-	memcpy_toio(data->pcc_comm_addr, (void *)value, data->ctx.length);
+	memcpy_toio(data->pcc_chan->shmem, (void *)value, data->ctx.length);

 	ret = mbox_send_message(data->pcc_chan->mchan, NULL);
 	if (ret < 0)
@@ -134,7 +125,7 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr,

 	mbox_chan_txdone(data->pcc_chan->mchan, ret);

-	memcpy_fromio(value, data->pcc_comm_addr, data->ctx.length);
+	memcpy_fromio(value, data->pcc_chan->shmem, data->ctx.length);

 	return AE_OK;
 }

-- 
2.34.1