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hwmon: (xgene) Stop writing PCC shared memory signature

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ACPI specification defines the generic PCC shared memory signature as
the PCC base signature ORed with the subspace ID.

ACPI 6.6 added clarification that the signature is populated by the
platform and verified by OSPM.

The PCC mailbox controller now validates the signature when the channel
is requested. Stop rewriting the signature before each command and
leave the platform-populated value intact.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
Link: https://lore.kernel.org/r/20260627-acpi_pcc_signature-v1-2-c1b7268d4fdc@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Sudeep Holla 2026-06-27 17:37:30 +01:00 committed by Guenter Roeck
parent 73a76fa6e8
commit 92ead3c1f1
1 changed files with 0 additions and 4 deletions
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4
drivers/hwmon/xgene-hwmon.c
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@ -133,10 +133,6 @@ static int xgene_hwmon_pcc_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
init_completion(&ctx->rd_complete);
ctx->resp_pending = true;
/* Write signature for subspace */
WRITE_ONCE(generic_comm_base->signature,
cpu_to_le32(PCC_SIGNATURE | ctx->mbox_idx));
/* Write to the shared command region */
WRITE_ONCE(generic_comm_base->command,
cpu_to_le16(MSG_TYPE(msg[0]) | PCC_CMD_GENERATE_DB_INTR));