can: can_check_bittiming_failed(): introduce function to check bittiming

include/can.h

@@ -49,7 +49,7 @@ typedef struct {
 extern const struct gs_device_bt_const CAN_btconst;
 
 void can_init(can_data_t *channel, CAN_TypeDef *instance);
-bool can_set_bittiming(can_data_t *channel, const struct gs_device_bittiming *timing);
+void can_set_bittiming(can_data_t *channel, const struct gs_device_bittiming *timing);
 void can_enable(can_data_t *channel, uint32_t mode);
 void can_disable(can_data_t *channel);
 bool can_is_enabled(can_data_t *channel);

include/can_common.h

@@ -31,6 +31,7 @@ THE SOFTWARE.
 #include "can.h"
 #include "usbd_gs_can.h"
 
+bool can_check_bittiming_ok(const struct can_bittiming_const *btc, const struct gs_device_bittiming *timing);
 void CAN_SendFrame(USBD_GS_CAN_HandleTypeDef *hcan, can_data_t *channel);
 void CAN_ReceiveFrame(USBD_GS_CAN_HandleTypeDef *hcan, can_data_t *channel);
 void CAN_HandleError(USBD_GS_CAN_HandleTypeDef *hcan, can_data_t *channel);

include/gs_usb.h

@@ -247,9 +247,7 @@ struct gs_device_bittiming {
 	u32 brp;
 } __packed __aligned(4);
 
-struct gs_device_bt_const {
-	u32 feature;
-	u32 fclk_can;
+struct can_bittiming_const {
 	u32 tseg1_min;
 	u32 tseg1_max;
 	u32 tseg2_min;
@@ -260,26 +258,17 @@ struct gs_device_bt_const {
 	u32 brp_inc;
 } __packed __aligned(4);
 
+struct gs_device_bt_const {
+	u32 feature;
+	u32 fclk_can;
+	struct can_bittiming_const btc;
+} __packed __aligned(4);
+
 struct gs_device_bt_const_extended {
 	u32 feature;
 	u32 fclk_can;
-	u32 tseg1_min;
-	u32 tseg1_max;
-	u32 tseg2_min;
-	u32 tseg2_max;
-	u32 sjw_max;
-	u32 brp_min;
-	u32 brp_max;
-	u32 brp_inc;
-
-	u32 dtseg1_min;
-	u32 dtseg1_max;
-	u32 dtseg2_min;
-	u32 dtseg2_max;
-	u32 dsjw_max;
-	u32 dbrp_min;
-	u32 dbrp_max;
-	u32 dbrp_inc;
+	struct can_bittiming_const btc;
+	struct can_bittiming_const dbtc;
 } __packed __aligned(4);
 
 struct gs_identify_mode {

src/can/bxcan.c

@@ -45,14 +45,16 @@ const struct gs_device_bt_const CAN_btconst = {
 #endif
 	,
 	.fclk_can = CAN_CLOCK_SPEED,
-	.tseg1_min = 1,
-	.tseg1_max = 16,
-	.tseg2_min = 1,
-	.tseg2_max = 8,
-	.sjw_max = 4,
-	.brp_min = 1,
-	.brp_max = 1024,
-	.brp_inc = 1,
+	.btc = {
+		.tseg1_min = 1,
+		.tseg1_max = 16,
+		.tseg2_min = 1,
+		.tseg2_max = 8,
+		.sjw_max = 4,
+		.brp_min = 1,
+		.brp_max = 1024,
+		.brp_inc = 1,
+	},
 };
 
 // The STM32F0 only has one CAN interface, define it as CAN1 as
@@ -84,23 +86,14 @@ void can_init(can_data_t *channel, CAN_TypeDef *instance)
 	device_can_init(channel, instance);
 }
 
-bool can_set_bittiming(can_data_t *channel, const struct gs_device_bittiming *timing)
+void can_set_bittiming(can_data_t *channel, const struct gs_device_bittiming *timing)
 {
 	const uint8_t tseg1 = timing->prop_seg + timing->phase_seg1;
 
-	if (  (timing->brp>0) && (timing->brp<=1024)
-	   && (tseg1>0) && (tseg1<=16)
-	   && (timing->phase_seg2>0) && (timing->phase_seg2<=8)
-	   && (timing->sjw>0) && (timing->sjw<=4)
-		  ) {
-		channel->brp = timing->brp & 0x3FF;
-		channel->phase_seg1 = tseg1;
-		channel->phase_seg2 = timing->phase_seg2;
-		channel->sjw = timing->sjw;
-		return true;
-	} else {
-		return false;
-	}
+	channel->brp = timing->brp;
+	channel->phase_seg1 = tseg1;
+	channel->phase_seg2 = timing->phase_seg2;
+	channel->sjw = timing->sjw;
 }
 
 void can_enable(can_data_t *channel, uint32_t mode)

src/can_common.c

@@ -29,6 +29,23 @@ THE SOFTWARE.
 #include "timer.h"
 #include "usbd_gs_can.h"
 
+bool can_check_bittiming_ok(const struct can_bittiming_const *btc,
+							const struct gs_device_bittiming *timing)
+{
+	const uint32_t tseg1 = timing->prop_seg + timing->phase_seg1;
+
+	if (tseg1 < btc->tseg1_min ||
+		tseg1 > btc->tseg1_max ||
+		timing->phase_seg2 < btc->tseg2_min ||
+		timing->phase_seg2 > btc->tseg2_max ||
+		timing->sjw > btc->sjw_max ||
+		timing->brp < btc->brp_min ||
+		timing->brp > btc->brp_max)
+		return false;
+
+	return true;
+}
+
 void CAN_SendFrame(USBD_GS_CAN_HandleTypeDef *hcan, can_data_t *channel)
 {
 	struct gs_host_frame_object *frame_object;

src/usbd_gs_can.c

@@ -28,6 +28,7 @@ THE SOFTWARE.
 #include <string.h>
 
 #include "can.h"
+#include "can_common.h"
 #include "compiler.h"
 #include "config.h"
 #include "gpio.h"
@@ -490,6 +491,9 @@ static uint8_t USBD_GS_CAN_EP0_RxReady(USBD_HandleTypeDef *pdev) {
 		case GS_USB_BREQ_BITTIMING: {
 			const struct gs_device_bittiming *timing = (struct gs_device_bittiming *)hcan->ep0_buf;
 
+			if (!can_check_bittiming_ok(&CAN_btconst.btc, timing))
+				goto out_fail;
+
 			can_set_bittiming(channel, timing);
 			break;
 		}
@@ -540,6 +544,9 @@ static uint8_t USBD_GS_CAN_EP0_RxReady(USBD_HandleTypeDef *pdev) {
 
 	req->bRequest = 0xFF;
 	return USBD_OK;
+
+out_fail:
+	return USBD_FAIL;
 }
 
 static uint8_t USBD_GS_CAN_DataIn(USBD_HandleTypeDef *pdev, uint8_t epnum) {