From d02a7327dd581fbe915667c5c3cc94c611f56a2c Mon Sep 17 00:00:00 2001
From: creatoy <creatoy@yeah.net>
Date: Thu, 22 Aug 2024 23:35:10 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E5=A4=8Di2c=E8=AF=BB=E5=8F=96?=
 =?UTF-8?q?=E6=95=B0=E6=8D=AE=E9=94=99=E8=AF=AF=E9=97=AE=E9=A2=98?=
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---
 drivers/i2c/busses/i2c_bcm2835_rust.rs | 18 ++++++++++++------
 rust/kernel/i2c.rs                     | 19 +++++++++++++++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c_bcm2835_rust.rs b/drivers/i2c/busses/i2c_bcm2835_rust.rs
index 419e405939f80..cc9977deadc23 100644
--- a/drivers/i2c/busses/i2c_bcm2835_rust.rs
+++ b/drivers/i2c/busses/i2c_bcm2835_rust.rs
@@ -302,15 +302,21 @@ impl Bcm2835I2cDev {
 
             // May Wrong!
             // if let Some(buf) = self.msg_buf.as_mut() {}
-
             if let Some(mut buf) = self.msg_buf.take() {
                 let idx = buf.len() - self.msg_buf_remaining;
                 buf[idx] = self.bcm2835_i2c_readl(BCM2835_I2C_FIFO) as u8;
                 pr_info!("\t{:x}", buf[idx]);
+                self.msg_buf = Some(buf);
                 self.msg_buf_remaining -= 1;
             }
-            pr_info!("\n");
         }
+        pr_info!("\n");
+        // let data = self.curr_msg[self.curr_msg_idx].buf_ptr();
+        let Some(msgs) = self.curr_msg.as_mut() else {
+            return;
+        };
+        let mut msg = msgs[self.curr_msg_idx].clone();
+        msg.write_to_buf(self.msg_buf.as_ref().unwrap());
     }
 
     pub(crate) fn bcm2835_i2c_start_transfer(&mut self) {
@@ -383,7 +389,7 @@ fn bcm2835_i2c_isr(this_irq: i32, i2c_dev: &mut Bcm2835I2cDev) -> irq::Return {
     if val & BCM2835_I2C_S_DONE != 0 {
         match i2c_dev.curr_msg {
             // Note: we represent the ptr buf with vec and the ptr to 0th element is the same as the ptr to the place in C.
-            Some(ref mut msgs) if msgs[i2c_dev.curr_msg_idx].flags() as u32 & I2C_M_RD != 0 => {
+            Some(ref msgs) if msgs[i2c_dev.curr_msg_idx].flags() as u32 & I2C_M_RD != 0 => {
                 i2c_dev.bcm2835_drain_rxfifo();
                 val = i2c_dev.bcm2835_i2c_readl(BCM2835_I2C_S);
                 pr_info!("drain readl: 0x{:04X}", val);
@@ -508,7 +514,7 @@ fn debug_print_status(i2c_dev: &Bcm2835I2cDev, d: &Bcm2835Debug) {
     )
 }
 
-fn debug_print_msg(i2c_dev: &Bcm2835I2cDev, msg: &I2cMsg, fname: &str, idx: i32, total: i32) {
+fn debug_print_msg(i2c_dev: &Bcm2835I2cDev, msg: &I2cMsg, idx: i32, total: i32, fname: &str) {
     let flags = msg.flags() as u32;
     pr_info!(
         "{fname}: msg({idx}/{total}) {} addr=0x{:02x}, len={} flags={}{}{}{}{}{}{} [i2c{}]\n",
@@ -560,9 +566,9 @@ fn debug_print(i2c_dev: &Bcm2835I2cDev, fname: &str) {
             debug_print_msg(
                 i2c_dev,
                 &d.msg,
-                fname,
                 d.msg_idx,
                 i2c_dev.debug_num_msgs as i32,
+                fname,
             );
         } else {
             debug_print_status(i2c_dev, d);
@@ -601,7 +607,7 @@ fn bcm2835_i2c_xfer(adap: &mut I2cAdapter, msgs: Vec<I2cMsg>, num: i32) -> Resul
     if DEBUG > 2 {
         let mut idx = 1;
         for msg in &msgs {
-            debug_print_msg(i2c_dev, &msg, "i2c_xfer", idx, num);
+            debug_print_msg(i2c_dev, &msg, idx, num, "i2c_xfer");
             idx += 1;
         }
     }
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index 08cd420a2b480..3fe7abf64d1d9 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs
@@ -97,6 +97,25 @@ impl I2cMsg {
         self.0.addr as u16
     }
 
+    pub fn buf_ptr(&self) -> *mut u8 {
+        self.0.buf
+    }
+
+    pub fn write_to_buf(&self, data: &[u8]) -> Option<usize> {
+        let data_ptr = data.as_ptr();
+        if data_ptr.is_null() || self.0.buf.is_null() {
+            return None;
+        }
+        let len = self.len() as usize;
+        let len = len.min(data.len());
+        // Safety: buf is valid for len bytes, no contiguity.
+        unsafe {
+            core::ptr::copy_nonoverlapping(data_ptr, self.0.buf, len);
+        }
+
+        Some(len)
+    }
+
     /// return buf of i2c_msg and transfer ownership of the buf
     pub fn buf_to_vec(&self) -> Option<Vec<u8>> {
         let len = self.len() as usize;