can: esd: add support for esd GmbH PCIe/402 CAN interface family

This patch adds support for the PCI based PCIe/402 CAN interface family
from esd GmbH that is available with various form factors
(https://esd.eu/en/products/402-series-can-interfaces).

All boards utilize a FPGA based CAN controller solution developed
by esd (esdACC). For more information on the esdACC see
https://esd.eu/en/products/esdacc.

This driver detects all available CAN interface board variants of
the family but atm. operates the CAN-FD capable devices in
Classic-CAN mode only! A later patch will introduce the CAN-FD
functionality in this driver.
Co-developed-by: Thomas Körper <thomas.koerper@esd.eu>
Signed-off-by: Thomas Körper <thomas.koerper@esd.eu>
Signed-off-by: Stefan Mätje <stefan.maetje@esd.eu>
Link: https://lore.kernel.org/all/20231122160211.2110448-3-stefan.maetje@esd.euSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/Kconfig

@@ -218,6 +218,7 @@ config CAN_XILINXCAN
 source "drivers/net/can/c_can/Kconfig"
 source "drivers/net/can/cc770/Kconfig"
 source "drivers/net/can/ctucanfd/Kconfig"
+source "drivers/net/can/esd/Kconfig"
 source "drivers/net/can/ifi_canfd/Kconfig"
 source "drivers/net/can/m_can/Kconfig"
 source "drivers/net/can/mscan/Kconfig"

drivers/net/can/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_CAN_VXCAN)		+= vxcan.o
 obj-$(CONFIG_CAN_SLCAN)		+= slcan/
 
 obj-y				+= dev/
+obj-y				+= esd/
 obj-y				+= rcar/
 obj-y				+= spi/
 obj-y				+= usb/

drivers/net/can/esd/Kconfig

+# SPDX-License-Identifier: GPL-2.0-only
+config CAN_ESD_402_PCI
+	tristate "esd electronics gmbh CAN-PCI(e)/402 family"
+	depends on PCI && HAS_DMA
+	help
+	  Support for C402 card family from esd electronics gmbh.
+	  This card family is based on the ESDACC CAN controller and
+	  available in several form factors:  PCI, PCIe, PCIe Mini,
+	  M.2 PCIe, CPCIserial, PMC, XMC  (see https://esd.eu/en)
+
+	  This driver can also be built as a module. In this case the
+	  module will be called esd_402_pci.

drivers/net/can/esd/Makefile

+# SPDX-License-Identifier: GPL-2.0-only
+#
+#  Makefile for esd gmbh ESDACC controller driver
+#
+esd_402_pci-objs := esdacc.o esd_402_pci-core.o
+
+obj-$(CONFIG_CAN_ESD_402_PCI) += esd_402_pci.o

drivers/net/can/esd/esdacc.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2015 - 2016 Thomas Körper, esd electronic system design gmbh
+ * Copyright (C) 2017 - 2023 Stefan Mätje, esd electronics gmbh
+ */
+
+#include <linux/bits.h>
+#include <linux/can/dev.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/units.h>
+
+#define ACC_TS_FREQ_80MHZ (80 * HZ_PER_MHZ)
+#define ACC_I2C_ADDON_DETECT_DELAY_MS 10
+
+/* esdACC Overview Module */
+#define ACC_OV_OF_PROBE	0x0000
+#define ACC_OV_OF_VERSION 0x0004
+#define ACC_OV_OF_INFO 0x0008
+#define ACC_OV_OF_CANCORE_FREQ 0x000c
+#define ACC_OV_OF_TS_FREQ_LO 0x0010
+#define ACC_OV_OF_TS_FREQ_HI 0x0014
+#define ACC_OV_OF_IRQ_STATUS_CORES 0x0018
+#define ACC_OV_OF_TS_CURR_LO 0x001c
+#define ACC_OV_OF_TS_CURR_HI 0x0020
+#define ACC_OV_OF_IRQ_STATUS 0x0028
+#define ACC_OV_OF_MODE 0x002c
+#define ACC_OV_OF_BM_IRQ_COUNTER 0x0070
+#define ACC_OV_OF_BM_IRQ_MASK 0x0074
+#define ACC_OV_OF_MSI_DATA 0x0080
+#define ACC_OV_OF_MSI_ADDRESSOFFSET 0x0084
+
+/* Feature flags are contained in the upper 16 bit of the version
+ * register at ACC_OV_OF_VERSION but only used with these masks after
+ * extraction into an extra variable => (xx - 16).
+ */
+#define ACC_OV_REG_FEAT_MASK_CANFD BIT(27 - 16)
+#define ACC_OV_REG_FEAT_MASK_NEW_PSC BIT(28 - 16)
+
+#define ACC_OV_REG_MODE_MASK_ENDIAN_LITTLE BIT(0)
+#define ACC_OV_REG_MODE_MASK_BM_ENABLE BIT(1)
+#define ACC_OV_REG_MODE_MASK_MODE_LED BIT(2)
+#define ACC_OV_REG_MODE_MASK_TIMER_ENABLE BIT(4)
+#define ACC_OV_REG_MODE_MASK_TIMER_ONE_SHOT BIT(5)
+#define ACC_OV_REG_MODE_MASK_TIMER_ABSOLUTE BIT(6)
+#define ACC_OV_REG_MODE_MASK_TIMER GENMASK(6, 4)
+#define ACC_OV_REG_MODE_MASK_TS_SRC GENMASK(8, 7)
+#define ACC_OV_REG_MODE_MASK_I2C_ENABLE BIT(11)
+#define ACC_OV_REG_MODE_MASK_MSI_ENABLE BIT(14)
+#define ACC_OV_REG_MODE_MASK_NEW_PSC_ENABLE BIT(15)
+#define ACC_OV_REG_MODE_MASK_FPGA_RESET BIT(31)
+
+/* esdACC CAN Core Module */
+#define ACC_CORE_OF_CTRL_MODE 0x0000
+#define ACC_CORE_OF_STATUS_IRQ 0x0008
+#define ACC_CORE_OF_BRP	0x000c
+#define ACC_CORE_OF_BTR	0x0010
+#define ACC_CORE_OF_FBTR 0x0014
+#define ACC_CORE_OF_STATUS 0x0030
+#define ACC_CORE_OF_TXFIFO_CONFIG 0x0048
+#define ACC_CORE_OF_TXFIFO_STATUS 0x004c
+#define ACC_CORE_OF_TX_STATUS_IRQ 0x0050
+#define ACC_CORE_OF_TX_ABORT_MASK 0x0054
+#define ACC_CORE_OF_BM_IRQ_COUNTER 0x0070
+#define ACC_CORE_OF_TXFIFO_ID 0x00c0
+#define ACC_CORE_OF_TXFIFO_DLC 0x00c4
+#define ACC_CORE_OF_TXFIFO_DATA_0 0x00c8
+#define ACC_CORE_OF_TXFIFO_DATA_1 0x00cc
+
+#define ACC_REG_CONTROL_MASK_MODE_RESETMODE BIT(0)
+#define ACC_REG_CONTROL_MASK_MODE_LOM BIT(1)
+#define ACC_REG_CONTROL_MASK_MODE_STM BIT(2)
+#define ACC_REG_CONTROL_MASK_MODE_TRANSEN BIT(5)
+#define ACC_REG_CONTROL_MASK_MODE_TS BIT(6)
+#define ACC_REG_CONTROL_MASK_MODE_SCHEDULE BIT(7)
+
+#define ACC_REG_CONTROL_MASK_IE_RXTX BIT(8)
+#define ACC_REG_CONTROL_MASK_IE_TXERROR BIT(9)
+#define ACC_REG_CONTROL_MASK_IE_ERRWARN BIT(10)
+#define ACC_REG_CONTROL_MASK_IE_OVERRUN BIT(11)
+#define ACC_REG_CONTROL_MASK_IE_TSI BIT(12)
+#define ACC_REG_CONTROL_MASK_IE_ERRPASS BIT(13)
+#define ACC_REG_CONTROL_MASK_IE_ALI BIT(14)
+#define ACC_REG_CONTROL_MASK_IE_BUSERR BIT(15)
+
+/* BRP and BTR register layout for CAN-Classic version */
+#define ACC_REG_BRP_CL_MASK_BRP GENMASK(8, 0)
+#define ACC_REG_BTR_CL_MASK_TSEG1 GENMASK(3, 0)
+#define ACC_REG_BTR_CL_MASK_TSEG2 GENMASK(18, 16)
+#define ACC_REG_BTR_CL_MASK_SJW GENMASK(25, 24)
+
+/* BRP and BTR register layout for CAN-FD version */
+#define ACC_REG_BRP_FD_MASK_BRP GENMASK(7, 0)
+#define ACC_REG_BTR_FD_MASK_TSEG1 GENMASK(7, 0)
+#define ACC_REG_BTR_FD_MASK_TSEG2 GENMASK(22, 16)
+#define ACC_REG_BTR_FD_MASK_SJW GENMASK(30, 24)
+
+/* 256 BM_MSGs of 32 byte size */
+#define ACC_CORE_DMAMSG_SIZE 32U
+#define ACC_CORE_DMABUF_SIZE (256U * ACC_CORE_DMAMSG_SIZE)
+
+enum acc_bmmsg_id {
+	BM_MSG_ID_RXTXDONE = 0x01,
+	BM_MSG_ID_TXABORT = 0x02,
+	BM_MSG_ID_OVERRUN = 0x03,
+	BM_MSG_ID_BUSERR = 0x04,
+	BM_MSG_ID_ERRPASSIVE = 0x05,
+	BM_MSG_ID_ERRWARN = 0x06,
+	BM_MSG_ID_TIMESLICE = 0x07,
+	BM_MSG_ID_HWTIMER = 0x08,
+	BM_MSG_ID_HOTPLUG = 0x09,
+};
+
+/* The struct acc_bmmsg_* structure declarations that follow here provide
+ * access to the ring buffer of bus master messages maintained by the FPGA
+ * bus master engine. All bus master messages have the same size of
+ * ACC_CORE_DMAMSG_SIZE and a minimum alignment of ACC_CORE_DMAMSG_SIZE in
+ * memory.
+ *
+ * All structure members are natural aligned. Therefore we should not need
+ * a __packed attribute. All struct acc_bmmsg_* declarations have at least
+ * reserved* members to fill the structure to the full ACC_CORE_DMAMSG_SIZE.
+ *
+ * A failure of this property due padding will be detected at compile time
+ * by static_assert(sizeof(union acc_bmmsg) == ACC_CORE_DMAMSG_SIZE).
+ */
+
+struct acc_bmmsg_rxtxdone {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 reserved1[2];
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u32 id;
+	struct {
+		u8 len;
+		u8 txdfifo_idx;
+		u8 zeroes8;
+		u8 reserved;
+	} acc_dlc;
+	u8 data[CAN_MAX_DLEN];
+	/* Time stamps in struct acc_ov::timestamp_frequency ticks. */
+	u64 ts;
+};
+
+struct acc_bmmsg_txabort {
+	u8 msg_id;
+	u8 txfifo_level;
+	u16 abort_mask;
+	u8 txtsfifo_level;
+	u8 reserved2[1];
+	u16 abort_mask_txts;
+	u64 ts;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_overrun {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 lost_cnt;
+	u8 reserved1;
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_buserr {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 ecc;
+	u8 reserved1;
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reg_status;
+	u32 reg_btr;
+	u32 reserved3[2];
+};
+
+struct acc_bmmsg_errstatechange {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 reserved1[2];
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reg_status;
+	u32 reserved3[3];
+};
+
+struct acc_bmmsg_timeslice {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 reserved1[2];
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_hwtimer {
+	u8 msg_id;
+	u8 reserved1[3];
+	u32 reserved2[1];
+	u64 timer;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_hotplug {
+	u8 msg_id;
+	u8 reserved1[3];
+	u32 reserved2[7];
+};
+
+union acc_bmmsg {
+	u8 msg_id;
+	struct acc_bmmsg_rxtxdone rxtxdone;
+	struct acc_bmmsg_txabort txabort;
+	struct acc_bmmsg_overrun overrun;
+	struct acc_bmmsg_buserr buserr;
+	struct acc_bmmsg_errstatechange errstatechange;
+	struct acc_bmmsg_timeslice timeslice;
+	struct acc_bmmsg_hwtimer hwtimer;
+};
+
+/* Check size of union acc_bmmsg to be of expected size. */
+static_assert(sizeof(union acc_bmmsg) == ACC_CORE_DMAMSG_SIZE);
+
+struct acc_bmfifo {
+	const union acc_bmmsg *messages;
+	/* irq_cnt points to an u32 value where the esdACC FPGA deposits
+	 * the bm_fifo head index in coherent DMA memory. Only bits 7..0
+	 * are valid. Use READ_ONCE() to access this memory location.
+	 */
+	const u32 *irq_cnt;
+	u32 local_irq_cnt;
+	u32 msg_fifo_tail;
+};
+
+struct acc_core {
+	void __iomem *addr;
+	struct net_device *netdev;
+	struct acc_bmfifo bmfifo;
+	u8 tx_fifo_size;
+	u8 tx_fifo_head;
+	u8 tx_fifo_tail;
+};
+
+struct acc_ov {
+	void __iomem *addr;
+	struct acc_bmfifo bmfifo;
+	u32 timestamp_frequency;
+	u32 core_frequency;
+	u16 version;
+	u16 features;
+	u8 total_cores;
+	u8 active_cores;
+};
+
+struct acc_net_priv {
+	struct can_priv can; /* must be the first member! */
+	struct acc_core *core;
+	struct acc_ov *ov;
+};
+
+static inline u32 acc_read32(struct acc_core *core, unsigned short offs)
+{
+	return ioread32be(core->addr + offs);
+}
+
+static inline void acc_write32(struct acc_core *core,
+			       unsigned short offs, u32 v)
+{
+	iowrite32be(v, core->addr + offs);
+}
+
+static inline void acc_write32_noswap(struct acc_core *core,
+				      unsigned short offs, u32 v)
+{
+	iowrite32(v, core->addr + offs);
+}
+
+static inline void acc_set_bits(struct acc_core *core,
+				unsigned short offs, u32 mask)
+{
+	u32 v = acc_read32(core, offs);
+
+	v |= mask;
+	acc_write32(core, offs, v);
+}
+
+static inline void acc_clear_bits(struct acc_core *core,
+				  unsigned short offs, u32 mask)
+{
+	u32 v = acc_read32(core, offs);
+
+	v &= ~mask;
+	acc_write32(core, offs, v);
+}
+
+static inline int acc_resetmode_entered(struct acc_core *core)
+{
+	u32 ctrl = acc_read32(core, ACC_CORE_OF_CTRL_MODE);
+
+	return (ctrl & ACC_REG_CONTROL_MASK_MODE_RESETMODE) != 0;
+}
+
+static inline u32 acc_ov_read32(struct acc_ov *ov, unsigned short offs)
+{
+	return ioread32be(ov->addr + offs);
+}
+
+static inline void acc_ov_write32(struct acc_ov *ov,
+				  unsigned short offs, u32 v)
+{
+	iowrite32be(v, ov->addr + offs);
+}
+
+static inline void acc_ov_set_bits(struct acc_ov *ov,
+				   unsigned short offs, u32 b)
+{
+	u32 v = acc_ov_read32(ov, offs);
+
+	v |= b;
+	acc_ov_write32(ov, offs, v);
+}
+
+static inline void acc_ov_clear_bits(struct acc_ov *ov,
+				     unsigned short offs, u32 b)
+{
+	u32 v = acc_ov_read32(ov, offs);
+
+	v &= ~b;
+	acc_ov_write32(ov, offs, v);
+}
+
+static inline void acc_reset_fpga(struct acc_ov *ov)
+{
+	acc_ov_write32(ov, ACC_OV_OF_MODE, ACC_OV_REG_MODE_MASK_FPGA_RESET);
+
+	/* (Re-)start and wait for completion of addon detection on the I^2C bus */
+	acc_ov_set_bits(ov, ACC_OV_OF_MODE, ACC_OV_REG_MODE_MASK_I2C_ENABLE);
+	mdelay(ACC_I2C_ADDON_DETECT_DELAY_MS);
+}
+
+void acc_init_ov(struct acc_ov *ov, struct device *dev);
+void acc_init_bm_ptr(struct acc_ov *ov, struct acc_core *cores,
+		     const void *mem);
+int acc_open(struct net_device *netdev);
+int acc_close(struct net_device *netdev);
+netdev_tx_t acc_start_xmit(struct sk_buff *skb, struct net_device *netdev);
+int acc_get_berr_counter(const struct net_device *netdev,
+			 struct can_berr_counter *bec);
+int acc_set_mode(struct net_device *netdev, enum can_mode mode);
+int acc_set_bittiming(struct net_device *netdev);
+irqreturn_t acc_card_interrupt(struct acc_ov *ov, struct acc_core *cores);