linux-kernel - [PATCH 1/5] cxl/acpi: Set ACPI's CXL

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Date:   Fri, 21 Oct 2022 13:56:11 -0500
From:   Terry Bowman <terry.bowman@....com>
To:     <alison.schofield@...el.com>, <vishal.l.verma@...el.com>,
        <dave.jiang@...el.com>, <ira.weiny@...el.com>,
        <bwidawsk@...nel.org>, <dan.j.williams@...el.com>
CC:     <terry.bowman@....com>, <linux-cxl@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <bhelgaas@...gle.com>,
        <rafael@...nel.org>, <lenb@...nel.org>,
        <Jonathan.Cameron@...wei.com>, <dave@...olabs.net>,
        <rrichter@....com>
Subject: [PATCH 1/5] cxl/acpi: Set ACPI's CXL _OSC to indicate CXL1.1 support

ACPI includes a CXL _OSC support method to communicate the available
CXL support to FW. The CXL support _OSC includes a field to indicate
CXL1.1 RCH RCD support. The OS sets this bit to 1 if it supports access
to RCD and RCH Port registers.[1] FW can potentially change it's operation
depending on the _OSC support setting reported by the OS.

The ACPI driver does not currently set the ACPI _OSC support to indicate
CXL1.1 RCD RCH support. Change the capability reported to include CXL1.1.

[1] CXL3.0 Table 9-26 'Interpretation of CXL _OSC Support Field'

Signed-off-by: Terry Bowman <terry.bowman@....com>
---
 drivers/acpi/pci_root.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index c8385ef54c37..094a59b216ae 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -492,6 +492,7 @@ static u32 calculate_cxl_support(void)
 	u32 support;
 
 	support = OSC_CXL_2_0_PORT_DEV_REG_ACCESS_SUPPORT;
+	support |= OSC_CXL_1_1_PORT_REG_ACCESS_SUPPORT;
 	if (pci_aer_available())
 		support |= OSC_CXL_PROTOCOL_ERR_REPORTING_SUPPORT;
 	if (IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
-- 
2.34.1