linux-kernel - [PATCH 1/3] i3c: master: Add inline i3c_master_readsl and i3c_master

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250620-i3c-writesl-readsl-v1-1-e0aa1c014dff@analog.com>
Date: Fri, 20 Jun 2025 18:54:59 +0200
From: Jorge Marques <jorge.marques@...log.com>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Frank Li
	<Frank.Li@....com>,
        Przemysław Gaj <pgaj@...ence.com>
CC: <linux-i3c@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        "Jorge
 Marques" <jorge.marques@...log.com>
Subject: [PATCH 1/3] i3c: master: Add inline i3c_master_readsl and
 i3c_master_writesl

The i3c abstraction excepts u8 buffers, but some controllers have a bus
width of 32-bits and don't support flagging valid bytes, so it is
required to read/write long words and to use memcpy on the remainder of
the number of bytes by 32-bits to not write/read outside the buffer
bounds.

Signed-off-by: Jorge Marques <jorge.marques@...log.com>
---
 include/linux/i3c/master.h | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index c67922ece617d6320c0c7e4838c2e7edda8c19f5..11401f2acb42e4d3a60df33b7c794d8a0360cdc2 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -674,6 +674,42 @@ i3c_master_get_bus(struct i3c_master_controller *master)
 	return &master->bus;
 }
 
+/**
+ * i3c_master_writesl- Write bytes to long memory region from byte array
+ * @addr: Register to write to
+ * @bytes: Pointer to the data bytes to write
+ * @nbytes: Number of bytes to write
+ */
+static inline void i3c_master_writesl(void __iomem *addr, const u8 *bytes,
+				      int nbytes)
+{
+writesl(addr, bytes, nbytes / 4);
+	if (nbytes & 3) {
+		u32 tmp = 0;
+
+		memcpy(&tmp, bytes + (nbytes & ~3), nbytes & 3);
+		writel(tmp, addr);
+	}
+}
+
+/**
+ * i3c_master_readsl - Read bytes from long memory region to byte array
+ * @addr: Register to read from
+ * @bytes: Pointer to the buffer to store read bytes
+ * @nbytes: Number of bytes to read
+ */
+static inline void i3c_master_readsl(const void __iomem *addr, u8 *bytes,
+				     int nbytes)
+{
+readsl(addr, bytes, nbytes / 4);
+	if (nbytes & 3) {
+		u32 tmp;
+
+		tmp = readl(addr);
+		memcpy(bytes + (nbytes & ~3), &tmp, nbytes & 3);
+	}
+}
+
 struct i3c_generic_ibi_pool;
 
 struct i3c_generic_ibi_pool *

-- 
2.49.0