zero: libcsp: Remove exit code from Linux driver

This commit adds the patch for resolve issue below.

The Linux USART driver for libcsp calls `exit()` API the rx_thread if
a read operation fails. This behavior terminates the entire process,
even if communication via interfaces other than USART is still possible.
Therefore, the exit() code will be removed.

Signed-off-by: Takuya Sasaki <takuya.sasaki@spacecubics.com>

zero/meta-libcsp/recipes-libcsp/files/0001-drivers-usart-Remove-exit-code-from-Linux-driver.patch

@@ -0,0 +1,40 @@
+From 90316c0f7fe41d1eac1d38d24b8d381c94d63466 Mon Sep 17 00:00:00 2001
+From: Takuya Sasaki <takuya.sasaki@spacecubics.com>
+Date: Wed, 20 Nov 2024 11:15:38 +0900
+Subject: [PATCH] drivers: usart: Remove exit() code from Linux driver
+
+The Linux USART driver for libcsp calls `exit()` API the rx_thread if
+a read operation fails. This behavior terminates the entire process,
+even if communication via interfaces other than USART is still possible.
+Therefore, the exit() code will be removed.
+
+Signed-off-by: Takuya Sasaki <takuya.sasaki@spacecubics.com>
+---
+ src/drivers/usart/usart_linux.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/src/drivers/usart/usart_linux.c b/src/drivers/usart/usart_linux.c
+index 48aa3d2..46d6539 100644
+--- a/src/drivers/usart/usart_linux.c
++++ b/src/drivers/usart/usart_linux.c
+@@ -38,7 +38,7 @@ static void * usart_rx_thread(void * arg) {
+ 	uint8_t * cbuf = malloc(CBUF_SIZE);
+ 	if (cbuf == NULL) {
+ 		csp_print("%s: malloc() failed, returned NULL\n", __func__);
+-		exit(1);
++		return NULL;
+ 	}
+
+ 	// Receive loop
+@@ -46,7 +46,7 @@ static void * usart_rx_thread(void * arg) {
+ 		int length = read(ctx->fd, cbuf, CBUF_SIZE);
+ 		if (length <= 0) {
+ 			csp_print("%s: read() failed, returned: %d\n", __func__, length);
+-			exit(1);
++			return NULL;
+ 		}
+ 		ctx->rx_callback(ctx->user_data, cbuf, length, NULL);
+ 	}
+-- 
+2.34.1
+

zero/meta-libcsp/recipes-libcsp/libcsp_0.bb

@@ -4,6 +4,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=2915dc85ab8fd26629e560d023ef175c"
 SRCREV = "${AUTOREV}"
 SRCBRANCH = "develop"
 SRC_URI = "git://github.com/libcsp/libcsp.git;protocol=https;branch=${SRCBRANCH};"
+SRC_URI += "file://0001-drivers-usart-Remove-exit-code-from-Linux-driver.patch"
 
 DEPENDS += "libsocketcan"