Merge tag 'linux-can-next-for-6.4-20230404-2' of...

Merge tag 'linux-can-next-for-6.4-20230404-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
pull-request: can-next 2023-04-04-2

The first patch is by Oliver Hartkopp and makes the maximum pdu size
of the CAN ISOTP protocol configurable.

The following 5 patches are by Dario Binacchi and add support for the
bxCAN controller by ST.

Geert Uytterhoeven's patch for the rcar_canfd driver fixes a sparse
warning.

Peng Fan's patch adds an optional power-domains property to the
flexcan device tree binding.

Frank Jungclaus adds support for CAN_CTRLMODE_BERR_REPORTING to the
esd_usb driver.

The last patch is by Oliver Hartkopp and converts the USB IDs of the
kvaser_usb driver to hexadecimal values.

* tag 'linux-can-next-for-6.4-20230404-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next:
  kvaser_usb: convert USB IDs to hexadecimal values
  can: esd_usb: Add support for CAN_CTRLMODE_BERR_REPORTING
  dt-bindings: can: fsl,flexcan: add optional power-domains property
  can: rcar_canfd: rcar_canfd_probe(): fix plain integer in transceivers[] init
  can: bxcan: add support for ST bxCAN controller
  ARM: dts: stm32: add pin map for CAN controller on stm32f4
  ARM: dts: stm32: add CAN support on stm32f429
  dt-bindings: net: can: add STM32 bxcan DT bindings
  dt-bindings: arm: stm32: add compatible for syscon gcan node
  can: isotp: add module parameter for maximum pdu size
====================

Link: https://lore.kernel.org/r/20230404145908.1714400-1-mkl@pengutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/devicetree/bindings/arm/stm32/st,stm32-syscon.yaml

@@ -20,6 +20,7 @@ properties:
               - st,stm32-syscfg
               - st,stm32-power-config
               - st,stm32-tamp
+              - st,stm32f4-gcan
           - const: syscon
       - items:
           - const: st,stm32-tamp
@@ -42,6 +43,7 @@ if:
       contains:
         enum:
           - st,stm32mp157-syscfg
+          - st,stm32f4-gcan
 then:
   required:
     - clocks

Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml

@@ -63,6 +63,9 @@ properties:
       boot loader. This property should only be used the used operating system
       doesn't support the clocks and clock-names property.
 
+  power-domains:
+    maxItems: 1
+
   xceiver-supply:
     description: Regulator that powers the CAN transceiver.
 

Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/can/st,stm32-bxcan.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics bxCAN controller
+
+description: STMicroelectronics BxCAN controller for CAN bus
+
+maintainers:
+  - Dario Binacchi <dario.binacchi@amarulasolutions.com>
+
+allOf:
+  - $ref: can-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - st,stm32f4-bxcan
+
+  st,can-primary:
+    description:
+      Primary and secondary mode of the bxCAN peripheral is only relevant
+      if the chip has two CAN peripherals. In that case they share some
+      of the required logic.
+      To avoid misunderstandings, it should be noted that ST documentation
+      uses the terms master/slave instead of primary/secondary.
+    type: boolean
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: transmit interrupt
+      - description: FIFO 0 receive interrupt
+      - description: FIFO 1 receive interrupt
+      - description: status change error interrupt
+
+  interrupt-names:
+    items:
+      - const: tx
+      - const: rx0
+      - const: rx1
+      - const: sce
+
+  resets:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  st,gcan:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description:
+      The phandle to the gcan node which allows to access the 512-bytes
+      SRAM memory shared by the two bxCAN cells (CAN1 primary and CAN2
+      secondary) in dual CAN peripheral configuration.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - resets
+  - clocks
+  - st,gcan
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/stm32fx-clock.h>
+    #include <dt-bindings/mfd/stm32f4-rcc.h>
+
+    can1: can@40006400 {
+        compatible = "st,stm32f4-bxcan";
+        reg = <0x40006400 0x200>;
+        interrupts = <19>, <20>, <21>, <22>;
+        interrupt-names = "tx", "rx0", "rx1", "sce";
+        resets = <&rcc STM32F4_APB1_RESET(CAN1)>;
+        clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
+        st,can-primary;
+        st,gcan = <&gcan>;
+    };

MAINTAINERS

@@ -4431,6 +4431,13 @@ S:	Maintained
 F:	drivers/scsi/BusLogic.*
 F:	drivers/scsi/FlashPoint.*
 
+BXCAN CAN NETWORK DRIVER
+M:	Dario Binacchi <dario.binacchi@amarulasolutions.com>
+L:	linux-can@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
+F:	drivers/net/can/bxcan.c
+
 C-MEDIA CMI8788 DRIVER
 M:	Clemens Ladisch <clemens@ladisch.de>
 L:	alsa-devel@alsa-project.org (moderated for non-subscribers)

arch/arm/boot/dts/stm32f4-pinctrl.dtsi

@@ -447,6 +447,36 @@ pins2 {
 					slew-rate = <2>;
 				};
 			};
+
+			can1_pins_a: can1-0 {
+				pins1 {
+					pinmux = <STM32_PINMUX('B', 9, AF9)>; /* CAN1_TX */
+				};
+				pins2 {
+					pinmux = <STM32_PINMUX('B', 8, AF9)>; /* CAN1_RX */
+					bias-pull-up;
+				};
+			};
+
+			can2_pins_a: can2-0 {
+				pins1 {
+					pinmux = <STM32_PINMUX('B', 13, AF9)>; /* CAN2_TX */
+				};
+				pins2 {
+					pinmux = <STM32_PINMUX('B', 5, AF9)>; /* CAN2_RX */
+					bias-pull-up;
+				};
+			};
+
+			can2_pins_b: can2-1 {
+				pins1 {
+					pinmux = <STM32_PINMUX('B', 13, AF9)>; /* CAN2_TX */
+				};
+				pins2 {
+					pinmux = <STM32_PINMUX('B', 12, AF9)>; /* CAN2_RX */
+					bias-pull-up;
+				};
+			};
 		};
 	};
 };

arch/arm/boot/dts/stm32f429.dtsi

@@ -362,6 +362,35 @@ i2c3: i2c@40005c00 {
 			status = "disabled";
 		};
 
+		can1: can@40006400 {
+			compatible = "st,stm32f4-bxcan";
+			reg = <0x40006400 0x200>;
+			interrupts = <19>, <20>, <21>, <22>;
+			interrupt-names = "tx", "rx0", "rx1", "sce";
+			resets = <&rcc STM32F4_APB1_RESET(CAN1)>;
+			clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
+			st,can-primary;
+			st,gcan = <&gcan>;
+			status = "disabled";
+		};
+
+		gcan: gcan@40006600 {
+			compatible = "st,stm32f4-gcan", "syscon";
+			reg = <0x40006600 0x200>;
+			clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
+		};
+
+		can2: can@40006800 {
+			compatible = "st,stm32f4-bxcan";
+			reg = <0x40006800 0x200>;
+			interrupts = <63>, <64>, <65>, <66>;
+			interrupt-names = "tx", "rx0", "rx1", "sce";
+			resets = <&rcc STM32F4_APB1_RESET(CAN2)>;
+			clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN2)>;
+			st,gcan = <&gcan>;
+			status = "disabled";
+		};
+
 		dac: dac@40007400 {
 			compatible = "st,stm32f4-dac-core";
 			reg = <0x40007400 0x400>;

drivers/net/can/Kconfig

@@ -93,6 +93,18 @@ config CAN_AT91
 	  This is a driver for the SoC CAN controller in Atmel's AT91SAM9263
 	  and AT91SAM9X5 processors.
 
+config CAN_BXCAN
+	tristate "STM32 Basic Extended CAN (bxCAN) devices"
+	depends on OF || ARCH_STM32 || COMPILE_TEST
+	depends on HAS_IOMEM
+	select CAN_RX_OFFLOAD
+	help
+	  Say yes here to build support for the STMicroelectronics STM32 basic
+	  extended CAN Controller (bxCAN).
+
+	  This driver can also be built as a module. If so, the module
+	  will be called bxcan.
+
 config CAN_CAN327
 	tristate "Serial / USB serial ELM327 based OBD-II Interfaces (can327)"
 	depends on TTY

drivers/net/can/Makefile

@@ -14,6 +14,7 @@ obj-y				+= usb/
 obj-y				+= softing/
 
 obj-$(CONFIG_CAN_AT91)		+= at91_can.o
+obj-$(CONFIG_CAN_BXCAN)		+= bxcan.o
 obj-$(CONFIG_CAN_CAN327)	+= can327.o
 obj-$(CONFIG_CAN_CC770)		+= cc770/
 obj-$(CONFIG_CAN_C_CAN)		+= c_can/

drivers/net/can/rcar/rcar_canfd.c

@@ -1848,7 +1848,7 @@ static void rcar_canfd_channel_remove(struct rcar_canfd_global *gpriv, u32 ch)
 
 static int rcar_canfd_probe(struct platform_device *pdev)
 {
-	struct phy *transceivers[RCANFD_NUM_CHANNELS] = { 0, };
+	struct phy *transceivers[RCANFD_NUM_CHANNELS] = { NULL, };
 	const struct rcar_canfd_hw_info *info;
 	struct device *dev = &pdev->dev;
 	void __iomem *addr;

drivers/net/can/usb/esd_usb.c

@@ -237,14 +237,23 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
 	if (id == ESD_EV_CAN_ERROR_EXT) {
 		u8 state = msg->rx.ev_can_err_ext.status;
 		u8 ecc = msg->rx.ev_can_err_ext.ecc;
-		u8 rxerr = msg->rx.ev_can_err_ext.rec;
-		u8 txerr = msg->rx.ev_can_err_ext.tec;
+
+		priv->bec.rxerr = msg->rx.ev_can_err_ext.rec;
+		priv->bec.txerr = msg->rx.ev_can_err_ext.tec;
 
 		netdev_dbg(priv->netdev,
 			   "CAN_ERR_EV_EXT: dlc=%#02x state=%02x ecc=%02x rec=%02x tec=%02x\n",
-			   msg->rx.dlc, state, ecc, rxerr, txerr);
+			   msg->rx.dlc, state, ecc,
+			   priv->bec.rxerr, priv->bec.txerr);
+
+		/* if berr-reporting is off, only pass through on state change ... */
+		if (!(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
+		    state == priv->old_state)
+			return;
 
 		skb = alloc_can_err_skb(priv->netdev, &cf);
+		if (!skb)
+			stats->rx_dropped++;
 
 		if (state != priv->old_state) {
 			enum can_state tx_state, rx_state;
@@ -265,14 +274,14 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
 				break;
 			default:
 				new_state = CAN_STATE_ERROR_ACTIVE;
-				txerr = 0;
-				rxerr = 0;
+				priv->bec.txerr = 0;
+				priv->bec.rxerr = 0;
 				break;
 			}
 
 			if (new_state != priv->can.state) {
-				tx_state = (txerr >= rxerr) ? new_state : 0;
-				rx_state = (txerr <= rxerr) ? new_state : 0;
+				tx_state = (priv->bec.txerr >= priv->bec.rxerr) ? new_state : 0;
+				rx_state = (priv->bec.txerr <= priv->bec.rxerr) ? new_state : 0;
 				can_change_state(priv->netdev, cf,
 						 tx_state, rx_state);
 			}
@@ -304,17 +313,12 @@ static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
 			cf->data[3] = ecc & SJA1000_ECC_SEG;
 		}
 
-		priv->bec.txerr = txerr;
-		priv->bec.rxerr = rxerr;
-
 		if (skb) {
 			cf->can_id |= CAN_ERR_CNT;
-			cf->data[6] = txerr;
-			cf->data[7] = rxerr;
+			cf->data[6] = priv->bec.txerr;
+			cf->data[7] = priv->bec.rxerr;
 
 			netif_rx(skb);
-		} else {
-			stats->rx_dropped++;
 		}
 	}
 }
@@ -1016,7 +1020,8 @@ static int esd_usb_probe_one_net(struct usb_interface *intf, int index)
 
 	priv->can.state = CAN_STATE_STOPPED;
 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY |
-		CAN_CTRLMODE_CC_LEN8_DLC;
+		CAN_CTRLMODE_CC_LEN8_DLC |
+		CAN_CTRLMODE_BERR_REPORTING;
 
 	if (le16_to_cpu(dev->udev->descriptor.idProduct) ==
 	    USB_CANUSBM_PRODUCT_ID)

drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c

@@ -31,63 +31,63 @@
 #include "kvaser_usb.h"
 
 /* Kvaser USB vendor id. */
-#define KVASER_VENDOR_ID			0x0bfd
+#define KVASER_VENDOR_ID 0x0bfd
 
 /* Kvaser Leaf USB devices product ids */
-#define USB_LEAF_DEVEL_PRODUCT_ID		10
-#define USB_LEAF_LITE_PRODUCT_ID		11
-#define USB_LEAF_PRO_PRODUCT_ID			12
-#define USB_LEAF_SPRO_PRODUCT_ID		14
-#define USB_LEAF_PRO_LS_PRODUCT_ID		15
-#define USB_LEAF_PRO_SWC_PRODUCT_ID		16
-#define USB_LEAF_PRO_LIN_PRODUCT_ID		17
-#define USB_LEAF_SPRO_LS_PRODUCT_ID		18
-#define USB_LEAF_SPRO_SWC_PRODUCT_ID		19
-#define USB_MEMO2_DEVEL_PRODUCT_ID		22
-#define USB_MEMO2_HSHS_PRODUCT_ID		23
-#define USB_UPRO_HSHS_PRODUCT_ID		24
-#define USB_LEAF_LITE_GI_PRODUCT_ID		25
-#define USB_LEAF_PRO_OBDII_PRODUCT_ID		26
-#define USB_MEMO2_HSLS_PRODUCT_ID		27
-#define USB_LEAF_LITE_CH_PRODUCT_ID		28
-#define USB_BLACKBIRD_SPRO_PRODUCT_ID		29
-#define USB_OEM_MERCURY_PRODUCT_ID		34
-#define USB_OEM_LEAF_PRODUCT_ID			35
-#define USB_CAN_R_PRODUCT_ID			39
-#define USB_LEAF_LITE_V2_PRODUCT_ID		288
-#define USB_MINI_PCIE_HS_PRODUCT_ID		289
-#define USB_LEAF_LIGHT_HS_V2_OEM_PRODUCT_ID	290
-#define USB_USBCAN_LIGHT_2HS_PRODUCT_ID		291
-#define USB_MINI_PCIE_2HS_PRODUCT_ID		292
-#define USB_USBCAN_R_V2_PRODUCT_ID		294
-#define USB_LEAF_LIGHT_R_V2_PRODUCT_ID		295
-#define USB_LEAF_LIGHT_HS_V2_OEM2_PRODUCT_ID	296
+#define USB_LEAF_DEVEL_PRODUCT_ID 0x000a
+#define USB_LEAF_LITE_PRODUCT_ID 0x000b
+#define USB_LEAF_PRO_PRODUCT_ID 0x000c
+#define USB_LEAF_SPRO_PRODUCT_ID 0x000e
+#define USB_LEAF_PRO_LS_PRODUCT_ID 0x000f
+#define USB_LEAF_PRO_SWC_PRODUCT_ID 0x0010
+#define USB_LEAF_PRO_LIN_PRODUCT_ID 0x0011
+#define USB_LEAF_SPRO_LS_PRODUCT_ID 0x0012
+#define USB_LEAF_SPRO_SWC_PRODUCT_ID 0x0013
+#define USB_MEMO2_DEVEL_PRODUCT_ID 0x0016
+#define USB_MEMO2_HSHS_PRODUCT_ID 0x0017
+#define USB_UPRO_HSHS_PRODUCT_ID 0x0018
+#define USB_LEAF_LITE_GI_PRODUCT_ID 0x0019
+#define USB_LEAF_PRO_OBDII_PRODUCT_ID 0x001a
+#define USB_MEMO2_HSLS_PRODUCT_ID 0x001b
+#define USB_LEAF_LITE_CH_PRODUCT_ID 0x001c
+#define USB_BLACKBIRD_SPRO_PRODUCT_ID 0x001d
+#define USB_OEM_MERCURY_PRODUCT_ID 0x0022
+#define USB_OEM_LEAF_PRODUCT_ID 0x0023
+#define USB_CAN_R_PRODUCT_ID 0x0027
+#define USB_LEAF_LITE_V2_PRODUCT_ID 0x0120
+#define USB_MINI_PCIE_HS_PRODUCT_ID 0x0121
+#define USB_LEAF_LIGHT_HS_V2_OEM_PRODUCT_ID 0x0122
+#define USB_USBCAN_LIGHT_2HS_PRODUCT_ID 0x0123
+#define USB_MINI_PCIE_2HS_PRODUCT_ID 0x0124
+#define USB_USBCAN_R_V2_PRODUCT_ID 0x0126
+#define USB_LEAF_LIGHT_R_V2_PRODUCT_ID 0x0127
+#define USB_LEAF_LIGHT_HS_V2_OEM2_PRODUCT_ID 0x0128
 
 /* Kvaser USBCan-II devices product ids */
-#define USB_USBCAN_REVB_PRODUCT_ID		2
-#define USB_VCI2_PRODUCT_ID			3
-#define USB_USBCAN2_PRODUCT_ID			4
-#define USB_MEMORATOR_PRODUCT_ID		5
+#define USB_USBCAN_REVB_PRODUCT_ID 0x0002
+#define USB_VCI2_PRODUCT_ID 0x0003
+#define USB_USBCAN2_PRODUCT_ID 0x0004
+#define USB_MEMORATOR_PRODUCT_ID 0x0005
 
 /* Kvaser Minihydra USB devices product ids */
-#define USB_BLACKBIRD_V2_PRODUCT_ID		258
-#define USB_MEMO_PRO_5HS_PRODUCT_ID		260
-#define USB_USBCAN_PRO_5HS_PRODUCT_ID		261
-#define USB_USBCAN_LIGHT_4HS_PRODUCT_ID		262
-#define USB_LEAF_PRO_HS_V2_PRODUCT_ID		263
-#define USB_USBCAN_PRO_2HS_V2_PRODUCT_ID	264
-#define USB_MEMO_2HS_PRODUCT_ID			265
-#define USB_MEMO_PRO_2HS_V2_PRODUCT_ID		266
-#define USB_HYBRID_2CANLIN_PRODUCT_ID		267
-#define USB_ATI_USBCAN_PRO_2HS_V2_PRODUCT_ID	268
-#define USB_ATI_MEMO_PRO_2HS_V2_PRODUCT_ID	269
-#define USB_HYBRID_PRO_2CANLIN_PRODUCT_ID	270
-#define USB_U100_PRODUCT_ID			273
-#define USB_U100P_PRODUCT_ID			274
-#define USB_U100S_PRODUCT_ID			275
-#define USB_USBCAN_PRO_4HS_PRODUCT_ID		276
-#define USB_HYBRID_CANLIN_PRODUCT_ID		277
-#define USB_HYBRID_PRO_CANLIN_PRODUCT_ID	278
+#define USB_BLACKBIRD_V2_PRODUCT_ID 0x0102
+#define USB_MEMO_PRO_5HS_PRODUCT_ID 0x0104
+#define USB_USBCAN_PRO_5HS_PRODUCT_ID 0x0105
+#define USB_USBCAN_LIGHT_4HS_PRODUCT_ID 0x0106
+#define USB_LEAF_PRO_HS_V2_PRODUCT_ID 0x0107
+#define USB_USBCAN_PRO_2HS_V2_PRODUCT_ID 0x0108
+#define USB_MEMO_2HS_PRODUCT_ID 0x0109
+#define USB_MEMO_PRO_2HS_V2_PRODUCT_ID 0x010a
+#define USB_HYBRID_2CANLIN_PRODUCT_ID 0x010b
+#define USB_ATI_USBCAN_PRO_2HS_V2_PRODUCT_ID 0x010c
+#define USB_ATI_MEMO_PRO_2HS_V2_PRODUCT_ID 0x010d
+#define USB_HYBRID_PRO_2CANLIN_PRODUCT_ID 0x010e
+#define USB_U100_PRODUCT_ID 0x0111
+#define USB_U100P_PRODUCT_ID 0x0112
+#define USB_U100S_PRODUCT_ID 0x0113
+#define USB_USBCAN_PRO_4HS_PRODUCT_ID 0x0114
+#define USB_HYBRID_CANLIN_PRODUCT_ID 0x0115
+#define USB_HYBRID_PRO_CANLIN_PRODUCT_ID 0x0116
 
 static const struct kvaser_usb_driver_info kvaser_usb_driver_info_hydra = {
 	.quirks = KVASER_USB_QUIRK_HAS_HARDWARE_TIMESTAMP,

net/can/isotp.c

@@ -85,10 +85,21 @@ MODULE_ALIAS("can-proto-6");
 
 /* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
  * take full 32 bit values (4 Gbyte). We would need some good concept to handle
- * this between user space and kernel space. For now increase the static buffer
- * to something about 64 kbyte to be able to test this new functionality.
+ * this between user space and kernel space. For now set the static buffer to
+ * something about 8 kbyte to be able to test this new functionality.
  */
-#define MAX_MSG_LENGTH 66000
+#define DEFAULT_MAX_PDU_SIZE 8300
+
+/* maximum PDU size before ISO 15765-2:2016 extension was 4095 */
+#define MAX_12BIT_PDU_SIZE 4095
+
+/* limit the isotp pdu size from the optional module parameter to 1MByte */
+#define MAX_PDU_SIZE (1025 * 1024U)
+
+static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
+module_param(max_pdu_size, uint, 0444);
+MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default "
+		 __stringify(DEFAULT_MAX_PDU_SIZE) ")");
 
 /* N_PCI type values in bits 7-4 of N_PCI bytes */
 #define N_PCI_SF 0x00	/* single frame */
@@ -123,13 +134,15 @@ enum {
 };
 
 struct tpcon {
-	unsigned int idx;
+	u8 *buf;
+	unsigned int buflen;
 	unsigned int len;
+	unsigned int idx;
 	u32 state;
 	u8 bs;
 	u8 sn;
 	u8 ll_dl;
-	u8 buf[MAX_MSG_LENGTH + 1];
+	u8 sbuf[DEFAULT_MAX_PDU_SIZE];
 };
 
 struct isotp_sock {
@@ -503,7 +516,17 @@ static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
 	if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
 		return 1;
 
-	if (so->rx.len > MAX_MSG_LENGTH) {
+	/* PDU size > default => try max_pdu_size */
+	if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
+		u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
+
+		if (newbuf) {
+			so->rx.buf = newbuf;
+			so->rx.buflen = max_pdu_size;
+		}
+	}
+
+	if (so->rx.len > so->rx.buflen) {
 		/* send FC frame with overflow status */
 		isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
 		return 1;
@@ -807,7 +830,7 @@ static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
 		cf->data[0] = so->opt.ext_address;
 
 	/* create N_PCI bytes with 12/32 bit FF_DL data length */
-	if (so->tx.len > 4095) {
+	if (so->tx.len > MAX_12BIT_PDU_SIZE) {
 		/* use 32 bit FF_DL notation */
 		cf->data[ae] = N_PCI_FF;
 		cf->data[ae + 1] = 0;
@@ -947,7 +970,17 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 		so->tx.state = ISOTP_SENDING;
 	}
 
-	if (!size || size > MAX_MSG_LENGTH) {
+	/* PDU size > default => try max_pdu_size */
+	if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
+		u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
+
+		if (newbuf) {
+			so->tx.buf = newbuf;
+			so->tx.buflen = max_pdu_size;
+		}
+	}
+
+	if (!size || size > so->tx.buflen) {
 		err = -EINVAL;
 		goto err_out_drop;
 	}
@@ -1195,6 +1228,12 @@ static int isotp_release(struct socket *sock)
 	so->ifindex = 0;
 	so->bound = 0;
 
+	if (so->rx.buf != so->rx.sbuf)
+		kfree(so->rx.buf);
+
+	if (so->tx.buf != so->tx.sbuf)
+		kfree(so->tx.buf);
+
 	sock_orphan(sk);
 	sock->sk = NULL;
 
@@ -1591,6 +1630,11 @@ static int isotp_init(struct sock *sk)
 	so->rx.state = ISOTP_IDLE;
 	so->tx.state = ISOTP_IDLE;
 
+	so->rx.buf = so->rx.sbuf;
+	so->tx.buf = so->tx.sbuf;
+	so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
+	so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
+
 	hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
 	so->rxtimer.function = isotp_rx_timer_handler;
 	hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
@@ -1658,7 +1702,10 @@ static __init int isotp_module_init(void)
 {
 	int err;
 
-	pr_info("can: isotp protocol\n");
+	max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE);
+	max_pdu_size = min_t(unsigned int, max_pdu_size, MAX_PDU_SIZE);
+
+	pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size);
 
 	err = can_proto_register(&isotp_can_proto);
 	if (err < 0)