Merge patch series "can: bxcan: add support for ST bxCAN controller"

Dario Binacchi <dario.binacchi@amarulasolutions.com> says:

The series adds support for the basic extended CAN controller (bxCAN)
found in many low- to middle-end STM32 SoCs.

The driver has been tested on the stm32f469i-discovery board with a
kernel version 5.19.0-rc2 in loopback + silent mode:

ip link set can0 type can bitrate 125000 loopback on listen-only on
ip link set up can0
candump can0 -L &
cansend can0 300#AC.AB.AD.AE.75.49.AD.D1

For uboot and kernel compilation, as well as for rootfs creation I used
buildroot:

make stm32f469_disco_sd_defconfig
make

but I had to patch can-utils and busybox as can-utils and iproute are
not compiled for MMU-less microcotrollers. In the case of can-utils,
replacing the calls to fork() with vfork(), I was able to compile the
package with working candump and cansend applications, while in the
case of iproute, I ran into more than one problem and finally I decided
to extend busybox's ip link command for CAN-type devices. I'm still
wondering if it was really necessary, but this way I was able to test
the driver.

Changes in v10: https://lore.kernel.org/all/20230328073328.3949796-1-dario.binacchi@amarulasolutions.com
- Fix errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'.
  Fix the "st,can-primary" description removing the "Note:" word that
  caused the failure.
- Slightly change the note text at the top of the driver module. No
  functional changes.

Changes in v9: https://lore.kernel.org/all/20230327201630.3874028-1-dario.binacchi@amarulasolutions.com
- Fix commit description formatting. No semantic changes have been made.
- Replace master/slave terms with primary/secondary.
- Replace master/slave terms with primary/secondary.
- Replace master/slave terms with primary/secondary.

Changes in v8: https://lore.kernel.org/all/20230326160325.3771891-1-dario.binacchi@amarulasolutions.com
- Do not enable the clock in probe and enable/disable it in open/close.
- Return IRQ_NONE if no IRQ is active.

Changes in v7: https://lore.kernel.org/all/20230116175152.2839455-1-dario.binacchi@amarulasolutions.com
- Add Vincent Mailhol's Reviewed-by tag.
- Remove all unused macros for reading/writing the controller registers.
- Add CAN_ERR_CNT flag to notify availability of error counter.
- Move the "break" before the newline in the switch/case statements.
- Print the mnemotechnic instead of the error value in each netdev_err().
- Remove the debug print for timings parameter.
- Do not copy the data if CAN_RTR_FLAG is set in bxcan_start_xmit().
- Populate ndev->ethtool_ops with the default timestamp info.

Changes in v6: https://lore.kernel.org/all/20230109182356.141849-1-dario.binacchi@amarulasolutions.com
- move can1 node before gcan to keep ordering by address.

Changes in v5: https://lore.kernel.org/all/20221017164231.4192699-1-dario.binacchi@amarulasolutions.com
- Add Rob Herring's Acked-by tag.
- Add Rob Herring's Reviewed-by tag.
- Put static in front of bxcan_enable_filters() definition.

Changes in v4: https://lore.kernel.org/all/20220925175209.1528960-1-dario.binacchi@amarulasolutions.com
- Remove "st,stm32f4-bxcan-core" compatible. In this way the can nodes
 (compatible "st,stm32f4-bxcan") are no longer children of a parent
  node with compatible "st,stm32f4-bxcan-core".
- Add the "st,gcan" property (global can memory) to can nodes which
  references a "syscon" node containing the shared clock and memory
  addresses.
- Replace the node can@40006400 (compatible "st,stm32f4-bxcan-core")
  with the gcan@40006600 node ("sysnode" compatible). The gcan node
  contains clocks and memory addresses shared by the two can nodes
  of which it's no longer the parent.
- Add to can nodes the "st,gcan" property (global can memory) which
  references the gcan@40006600 node ("sysnode compatibble).
- Add "dt-bindings: arm: stm32: add compatible for syscon gcan node" patch.
- Drop the core driver. Thus bxcan-drv.c has been renamed to bxcan.c and
  moved to the drivers/net/can folder. The drivers/net/can/bxcan directory
  has therefore been removed.
- Use the regmap_*() functions to access the shared memory registers.
- Use spinlock to protect bxcan_rmw().
- Use 1 space, instead of tabs, in the macros definition.
- Drop clock ref-counting.
- Drop unused code.
- Drop the _SHIFT macros and use FIELD_GET()/FIELD_PREP() directly.
- Add BXCAN_ prefix to lec error codes.
- Add the macro BXCAN_RX_MB_NUM.
- Enable time triggered mode and use can_rx_offload().
- Use readx_poll_timeout() in function with timeouts.
- Loop from tail to head in bxcan_tx_isr().
- Check bits of tsr register instead of pkts variable in bxcan_tx_isr().
- Don't return from bxcan_handle_state_change() if skb/cf are NULL.
- Enable/disable the generation of the bus error interrupt depending
  on can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING.
- Don't return from bxcan_handle_bus_err() if skb is NULL.
- Drop statistics updating from bxcan_handle_bus_err().
- Add an empty line in front of 'return IRQ_HANDLED;'
- Rename bxcan_start() to bxcan_chip_start().
- Rename bxcan_stop() to bxcan_chip_stop().
- Disable all IRQs in bxcan_chip_stop().
- Rename bxcan_close() to bxcan_ndo_stop().
- Use writel instead of bxcan_rmw() to update the dlc register.

Changes in v3: https://lore.kernel.org/all/20220828133329.793324-1-dario.binacchi@amarulasolutions.com
- Remove 'Dario Binacchi <dariobin@libero.it>' SOB.
- Add description to the parent of the two child nodes.
- Move "patterProperties:" after "properties: in top level before "required".
- Add "clocks" to the "required:" list of the child nodes.
- Remove 'Dario Binacchi <dariobin@libero.it>' SOB.
- Add "clocks" to can@0 node.
- Remove 'Dario Binacchi <dariobin@libero.it>' SOB.
- Remove a blank line.
- Remove 'Dario Binacchi <dariobin@libero.it>' SOB.
- Fix the documentation file path in the MAINTAINERS entry.
- Do not increment the "stats->rx_bytes" if the frame is remote.
- Remove pr_debug() call from bxcan_rmw().

Changes in v2: https://lore.kernel.org/all/20220820082936.686924-1-dario.binacchi@amarulasolutions.com
- Change the file name into 'st,stm32-bxcan-core.yaml'.
- Rename compatibles:
  - st,stm32-bxcan-core -> st,stm32f4-bxcan-core
  - st,stm32-bxcan -> st,stm32f4-bxcan
- Rename master property to st,can-master.
- Remove the status property from the example.
- Put the node child properties as required.
- Remove a blank line.
- Fix sparse errors.
- Create a MAINTAINERS entry.
- Remove the print of the registers address.
- Remove the volatile keyword from bxcan_rmw().
- Use tx ring algorithm to manage tx mailboxes.
- Use can_{get|put}_echo_skb().
- Update DT properties.

v1: https://lore.kernel.org/all/20220817143529.257908-1-dario.binacchi@amarulasolutions.com

Link: https://lore.kernel.org/all/20230328073328.3949796-1-dario.binacchi@amarulasolutions.comSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

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/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/