Received-SPF: pass (google.com: domain of linux-kernel+bounces-103686-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: Armin Wolf <W_Armin@gmx.de>
To: hdegoede@redhat.com,
	ilpo.jarvinen@linux.intel.com
Cc: rafael@kernel.org,
	lenb@kernel.org,
	mario.limonciello@amd.com,
	sathyanarayanan.kuppuswamy@linux.intel.com,
	linux-acpi@vger.kernel.org,
	platform-driver-x86@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5 1/2] platform/x86: wmi: Support reading/writing 16 bit EC values
Date: Thu, 14 Mar 2024 19:45:37 +0100
Message-Id: <20240314184538.2933-1-W_Armin@gmx.de>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
UI-OutboundReport: notjunk:1;M01:P0:FabCNjlmGVU=;O794OGRdPae3dIb4R1gaWQv8KA9
 K8mT4uQ3b5lB08wTSukck2bRDH5MMDcSlkRUiOz1CLci1V9cixwE1CB6aM/rhdGlvc8IiOjwh
 1LXM6N4DMeVbL3nsDRo+EoM66MswaECp8q6SMUmiZPhvBd3uWMtyF0VZwMxSC/kCwrFF2gPpz
 XKmrIV4p0jL0cCkhFhzOILbSAzJzeNpcTzpKvq2hScckdVmENGe76CLaZzJvg5wA2rxH28JJY
 Co93bkDu45B8ugjVgfkF2PMXdnYTDO56EXmZjp8qY3LAriXJSPLvc31sf3VxhbJIj7qtIOHqP
 cGodsui0KXrp9U/0h6hZP/jMnYeTnBQFUUIVx0uwLTynwPMscyDX/4A7EZx1huYlHgmEg38UI
 277nnnfBkpJmh+RYj0yqakvfKMQ35kiM53Qwvn/bCu1F/vDi553yR7DcLMH3vO+vcK2gtnJx0
 TGI55mlV1Uf42np2fdhDLAxDFryyG0nCCGhXrohwdpx9T5pGmKn0yS/DLjkIc6dEjaci5fkyv
 1l7Eq6u03+H9zaXfaYPBGA68A+ip7lmT3r7POfdOG/ZZC86rt3LmLgWmkow5GB4AVLbOOR1AT
 iKnYRggAaU1cIiSdxyQgjKZ4J9lzrAihm9+6vjYnSi1Q3LDKFZQtMKt/VjTaZ2L92ZcVP6t6s
 kwfsfU4rK7+Qj1Ke51vMbapEVd84JxPqbuS4xzAJ438kHWlxSN1ATPFb/9xhWwkl8xyVPJcz3
 PpgS+4e3NGkZM306xo3sqFknpo5yhreyOyX2QWSUHAUCb224lZaQGDYBAHc4KbWiC0sY/DmUF
 VD0W3IjMx4gyRZpcYGOtH5gabCHnuMmh01cOXk3dKfRsQ=

The ACPI EC address space handler currently only supports
reading/writing 8 bit values. Some firmware implementations however
want to access for example 16 bit values, which is perfectly legal
according to the ACPI spec.

Add support for reading/writing such values.

Tested on a Dell Inspiron 3505 and a Asus Prime B650-Plus.

Reviewed-by: Ilpo J=C3=A4rvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
=2D--
Chnages since v4:
- spelling fix
- fix checkpatch warning

Changes since v3:
- change type of variable i to size_t

Changes since v2:
- fix address overflow check

Changes since v1:
- use BITS_PER_BYTE
- validate that number of bytes to read/write does not overflow the
  address
=2D--
 drivers/platform/x86/wmi.c | 54 +++++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 1920e115da89..9602658711cf 100644
=2D-- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1153,6 +1153,34 @@ static int parse_wdg(struct device *wmi_bus_dev, st=
ruct platform_device *pdev)
 	return 0;
 }

+static int ec_read_multiple(u8 address, u8 *buffer, size_t bytes)
+{
+	size_t i;
+	int ret;
+
+	for (i =3D 0; i < bytes; i++) {
+		ret =3D ec_read(address + i, &buffer[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ec_write_multiple(u8 address, u8 *buffer, size_t bytes)
+{
+	size_t i;
+	int ret;
+
+	for (i =3D 0; i < bytes; i++) {
+		ret =3D ec_write(address + i, buffer[i]);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
 /*
  * WMI can have EmbeddedControl access regions. In which case, we just wa=
nt to
  * hand these off to the EC driver.
@@ -1162,27 +1190,27 @@ acpi_wmi_ec_space_handler(u32 function, acpi_physi=
cal_address address,
 			  u32 bits, u64 *value,
 			  void *handler_context, void *region_context)
 {
-	int result =3D 0;
-	u8 temp =3D 0;
+	int bytes =3D bits / BITS_PER_BYTE;
+	int ret;

-	if ((address > 0xFF) || !value)
+	if (!value)
+		return AE_NULL_ENTRY;
+
+	if (!bytes || bytes > sizeof(*value))
 		return AE_BAD_PARAMETER;

-	if (function !=3D ACPI_READ && function !=3D ACPI_WRITE)
+	if (address > U8_MAX || address + bytes - 1 > U8_MAX)
 		return AE_BAD_PARAMETER;

-	if (bits !=3D 8)
+	if (function !=3D ACPI_READ && function !=3D ACPI_WRITE)
 		return AE_BAD_PARAMETER;

-	if (function =3D=3D ACPI_READ) {
-		result =3D ec_read(address, &temp);
-		*value =3D temp;
-	} else {
-		temp =3D 0xff & *value;
-		result =3D ec_write(address, temp);
-	}
+	if (function =3D=3D ACPI_READ)
+		ret =3D ec_read_multiple(address, (u8 *)value, bytes);
+	else
+		ret =3D ec_write_multiple(address, (u8 *)value, bytes);

-	switch (result) {
+	switch (ret) {
 	case -EINVAL:
 		return AE_BAD_PARAMETER;
 	case -ENODEV:
=2D-
2.39.2