diff options
Diffstat (limited to 'drivers/net/ethernet/freescale/enetc/enetc_ierb.c')
| -rw-r--r-- | drivers/net/ethernet/freescale/enetc/enetc_ierb.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_ierb.c b/drivers/net/ethernet/freescale/enetc/enetc_ierb.c new file mode 100644 index 000000000000..8b356c485507 --- /dev/null +++ b/drivers/net/ethernet/freescale/enetc/enetc_ierb.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) +/* Copyright 2021 NXP Semiconductors + * + * The Integrated Endpoint Register Block (IERB) is configured by pre-boot + * software and is supposed to be to ENETC what a NVRAM is to a 'real' PCIe + * card. Upon FLR, values from the IERB are transferred to the ENETC PFs, and + * are read-only in the PF memory space. + * + * This driver fixes up the power-on reset values for the ENETC shared FIFO, + * such that the TX and RX allocations are sufficient for jumbo frames, and + * that intelligent FIFO dropping is enabled before the internal data + * structures are corrupted. + * + * Even though not all ports might be used on a given board, we are not + * concerned with partitioning the FIFO, because the default values configure + * no strict reservations, so the entire FIFO can be used by the RX of a single + * port, or the TX of a single port. + */ + +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/pci.h> +#include <linux/platform_device.h> +#include "enetc.h" +#include "enetc_ierb.h" + +/* IERB registers */ +#define ENETC_IERB_TXMBAR(port) (((port) * 0x100) + 0x8080) +#define ENETC_IERB_RXMBER(port) (((port) * 0x100) + 0x8090) +#define ENETC_IERB_RXMBLR(port) (((port) * 0x100) + 0x8094) +#define ENETC_IERB_RXBCR(port) (((port) * 0x100) + 0x80a0) +#define ENETC_IERB_TXBCR(port) (((port) * 0x100) + 0x80a8) +#define ENETC_IERB_FMBDTR 0xa000 + +#define ENETC_RESERVED_FOR_ICM 1024 + +struct enetc_ierb { + void __iomem *regs; +}; + +static void enetc_ierb_write(struct enetc_ierb *ierb, u32 offset, u32 val) +{ + iowrite32(val, ierb->regs + offset); +} + +int enetc_ierb_register_pf(struct platform_device *pdev, + struct pci_dev *pf_pdev) +{ + struct enetc_ierb *ierb = platform_get_drvdata(pdev); + int port = enetc_pf_to_port(pf_pdev); + u16 tx_credit, rx_credit, tx_alloc; + + if (port < 0) + return -ENODEV; + + if (!ierb) + return -EPROBE_DEFER; + + /* By default, it is recommended to set the Host Transfer Agent + * per port transmit byte credit to "1000 + max_frame_size/2". + * The power-on reset value (1800 bytes) is rounded up to the nearest + * 100 assuming a maximum frame size of 1536 bytes. + */ + tx_credit = roundup(1000 + ENETC_MAC_MAXFRM_SIZE / 2, 100); + + /* Internal memory allocated for transmit buffering is guaranteed but + * not reserved; i.e. if the total transmit allocation is not used, + * then the unused portion is not left idle, it can be used for receive + * buffering but it will be reclaimed, if required, from receive by + * intelligently dropping already stored receive frames in the internal + * memory to ensure that the transmit allocation is respected. + * + * PaTXMBAR must be set to a value larger than + * PaTXBCR + 2 * max_frame_size + 32 + * if frame preemption is not enabled, or to + * 2 * PaTXBCR + 2 * p_max_frame_size (pMAC maximum frame size) + + * 2 * np_max_frame_size (eMAC maximum frame size) + 64 + * if frame preemption is enabled. + */ + tx_alloc = roundup(2 * tx_credit + 4 * ENETC_MAC_MAXFRM_SIZE + 64, 16); + + /* Initial credits, in units of 8 bytes, to the Ingress Congestion + * Manager for the maximum amount of bytes the port is allocated for + * pending traffic. + * It is recommended to set the initial credits to 2 times the maximum + * frame size (2 frames of maximum size). + */ + rx_credit = DIV_ROUND_UP(ENETC_MAC_MAXFRM_SIZE * 2, 8); + + enetc_ierb_write(ierb, ENETC_IERB_TXBCR(port), tx_credit); + enetc_ierb_write(ierb, ENETC_IERB_TXMBAR(port), tx_alloc); + enetc_ierb_write(ierb, ENETC_IERB_RXBCR(port), rx_credit); + + return 0; +} +EXPORT_SYMBOL(enetc_ierb_register_pf); + +static int enetc_ierb_probe(struct platform_device *pdev) +{ + struct enetc_ierb *ierb; + struct resource *res; + void __iomem *regs; + + ierb = devm_kzalloc(&pdev->dev, sizeof(*ierb), GFP_KERNEL); + if (!ierb) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(regs)) + return PTR_ERR(regs); + + ierb->regs = regs; + + /* Free buffer depletion threshold in bytes. + * This sets the minimum amount of free buffer memory that should be + * maintained in the datapath sub system, and when the amount of free + * buffer memory falls below this threshold, a depletion indication is + * asserted, which may trigger "intelligent drop" frame releases from + * the ingress queues in the ICM. + * It is recommended to set the free buffer depletion threshold to 1024 + * bytes, since the ICM needs some FIFO memory for its own use. + */ + enetc_ierb_write(ierb, ENETC_IERB_FMBDTR, ENETC_RESERVED_FOR_ICM); + + platform_set_drvdata(pdev, ierb); + + return 0; +} + +static int enetc_ierb_remove(struct platform_device *pdev) +{ + return 0; +} + +static const struct of_device_id enetc_ierb_match[] = { + { .compatible = "fsl,ls1028a-enetc-ierb", }, + {}, +}; +MODULE_DEVICE_TABLE(of, enetc_ierb_match); + +static struct platform_driver enetc_ierb_driver = { + .driver = { + .name = "fsl-enetc-ierb", + .of_match_table = enetc_ierb_match, + }, + .probe = enetc_ierb_probe, + .remove = enetc_ierb_remove, +}; + +module_platform_driver(enetc_ierb_driver); + +MODULE_DESCRIPTION("NXP ENETC IERB"); +MODULE_LICENSE("Dual BSD/GPL"); |