From 4b1651a1a37fe6d092d3eb37cadc977956bf89d1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Thu, 27 Feb 2020 13:06:29 +0100
Subject: [PATCH] i2c_master: fix writing function to cope with read function
 now including a stop

---
 lib/i2c_master.c | 44 +++++++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/lib/i2c_master.c b/lib/i2c_master.c
index a65bd31..5172cfe 100644
--- a/lib/i2c_master.c
+++ b/lib/i2c_master.c
@@ -670,22 +670,39 @@ enum i2c_master_rc i2c_master_address_read(uint32_t i2c, uint16_t slave, bool ad
 		if (I2C_MASTER_RC_NONE != rc) {
 			goto error;
 		}
-		rc = i2c_master_read(i2c, data, data_size); // read memory
+		rc = i2c_master_read(i2c, data, data_size); // read memory (includes stop)
 		if (I2C_MASTER_RC_NONE != rc) {
 			goto error;
 		}
+	} else {
+		i2c_master_stop(i2c); // sent stop condition
 	}
 
-	rc = I2C_MASTER_RC_NONE; // all went well
+	rc = I2C_MASTER_RC_NONE;
 error:
-	i2c_master_stop(i2c); // sent stop condition
+	if (I2C_MASTER_RC_NONE != rc) { // only send stop on error
+		i2c_master_stop(i2c); // sent stop condition
+	}
 	return rc;
 }
 
 enum i2c_master_rc i2c_master_address_write(uint32_t i2c, uint16_t slave, bool address_10bit, const uint8_t* address, size_t address_size, const uint8_t* data, size_t data_size)
 {
 	cm3_assert(I2C1 == i2c || I2C2 == i2c);
+	if (SIZE_MAX - address_size < data_size) { // prevent integer overflow
+		return I2C_MASTER_RC_OTHER;
+	}
+	if (address_size + data_size > 10 * 1024) { // we won't enough RAM
+		return I2C_MASTER_RC_OTHER;
+	}
+	if (address_size > 0 && NULL == address) {
+		return I2C_MASTER_RC_OTHER;
+	}
+	if (data_size > 0 && NULL == data) {
+		return I2C_MASTER_RC_OTHER;
+	}
 
+	uint8_t buffer[address_size + data_size];
 	enum i2c_master_rc rc = I2C_MASTER_RC_NONE; // to store I²C return codes
 	rc = i2c_master_start(i2c); // send (re-)start condition
 	if (I2C_MASTER_RC_NONE != rc) {
@@ -696,20 +713,21 @@ enum i2c_master_rc i2c_master_address_write(uint32_t i2c, uint16_t slave, bool a
 		goto error;
 	}
 
-	// write address
-	if (NULL != address && address_size > 0) {
-		rc = i2c_master_write(i2c, address, address_size); // send memory address
-		if (I2C_MASTER_RC_NONE != rc) {
-			goto error;
+	// we can't send the address then the data size short address will cause a stop (because of how crappy the STM32F10x I²C peripheral is)
+	if (address) {
+		for (size_t i = 0; i < address_size; i++) {
+			buffer[i] = address[i];
 		}
 	}
-	// read data
-	if (NULL != data && data_size > 0) {
-		rc = i2c_master_write(i2c, data, data_size); // write memory
-		if (I2C_MASTER_RC_NONE != rc) {
-			goto error;
+	if (data) {
+		for (size_t i = 0; i < data_size; i++) {
+			buffer[address_size + i] = data[i];
 		}
 	}
+	rc = i2c_master_write(i2c, buffer, address_size + data_size); // send memory address
+	if (I2C_MASTER_RC_NONE != rc) {
+		goto error;
+	}
 
 error:
 	rc = i2c_master_stop(i2c); // sent stop condition