Re: [PATCH 2/3] mailbox: Add Broadcom PDC mailbox driver

Jassi Brar
2016-06-26T06:31:43Z

On Tue, May 24, 2016 at 11:37 PM, Rob Rice <rob.rice-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> wrote:
> From: Rob Rice <rrice-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
>
> The Broadcom PDC mailbox driver is a mailbox controller that
> manages data transfers to and from one or more offload engines.
>
> Signed-off-by: Rob Rice <rob.rice-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> Reviewed-by: Scott Branden <scott.branden-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> Reviewed-by: Ray Jui <ray.jui-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> ---
> drivers/mailbox/Kconfig | 9 +
> drivers/mailbox/Makefile | 2 +
> drivers/mailbox/mailbox-pdc/Makefile | 8 +
> drivers/mailbox/mailbox-pdc/pdc.c | 1181 +++++++++++++++++++++++++++++++
> drivers/mailbox/mailbox-pdc/pdc.h | 303 ++++++++
> drivers/mailbox/mailbox-pdc/pdc_debug.c | 101 +++
> drivers/mailbox/mailbox-pdc/pdc_debug.h | 24 +
>
We already have mailbox api testing rig - mailbox-test, still if you
really need debugfs exposure please merge it in pdc.c especially when
pdc_debug.c is only 80lines and it always compiled and currently has
to export functions globally. Maybe fold everything in a single like
other platforms?

> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index 5305923..19c8c9a 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -123,4 +123,13 @@ config XGENE_SLIMPRO_MBOX
> It is used to send short messages between ARM64-bit cores and
> the SLIMpro Management Engine, primarily for PM. Say Y here if you
> want to use the APM X-Gene SLIMpro IPCM support.
> +
> +config BCM_PDC_MBOX
> + tristate "Broadcom PDC Mailbox"
> + depends on ARM64
> + default ARCH_BCM_IPROC
> + help
> + Mailbox implementation for the Broadcom PDC ring manager,
> + which provides access to various offload engines on Broadcom
> + SoCs. Say Y here if you want to use the Broadcom PDC.
> endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index 0be3e74..2c14a03 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -25,3 +25,5 @@ obj-$(CONFIG_TI_MESSAGE_MANAGER) += ti-msgmgr.o
> obj-$(CONFIG_XGENE_SLIMPRO_MBOX) += mailbox-xgene-slimpro.o
>
> obj-$(CONFIG_HI6220_MBOX) += hi6220-mailbox.o
> +
> +obj-$(CONFIG_BCM_PDC_MBOX) += mailbox-pdc/
> diff --git a/drivers/mailbox/mailbox-pdc/Makefile b/drivers/mailbox/mailbox-pdc/Makefile
> new file mode 100644
> index 0000000..5dc78c3
> --- /dev/null
> +++ b/drivers/mailbox/mailbox-pdc/Makefile
> @@ -0,0 +1,8 @@
> +# Makefile for Broadcom PDC Mailbox driver
> +
> +# Uncomment to enable debug tracing in the PDC driver
> +# CFLAGS_pdc.o := -DDEBUG
> +# CFLAGS_pdc_debug.o := -DDEBUG
> +
> +pdc-mbox-objs := pdc.o pdc_debug.o
> +obj-$(CONFIG_BCM_PDC_MBOX) := pdc-mbox.o
> diff --git a/drivers/mailbox/mailbox-pdc/pdc.c b/drivers/mailbox/mailbox-pdc/pdc.c
> new file mode 100644
> index 0000000..1c24ea8
> --- /dev/null
> +++ b/drivers/mailbox/mailbox-pdc/pdc.c
> @@ -0,0 +1,1181 @@
> +/*
> + * Copyright 2016 Broadcom
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation (the "GPL").
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License version 2 (GPLv2) for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * version 2 (GPLv2) along with this source code.
> + */
> +
> +/*
> + * Broadcom PDC Mailbox Driver
> + * The PDC provides a ring based programming interface to one or more hardware
> + * offload engines. For example, the PDC driver works with both SPU-M and SPU2
> + * cryptographic offload hardware. In some chips the PDC is referred to as MDE.
> + *
> + * The PDC driver registers with the Linux mailbox framework as a mailbox
> + * controller, once for each PDC instance. Ring 0 for each PDC is registered as
> + * a mailbox channel. The PDC driver uses interrupts to determine when data
> + * transfers to and from an offload engine are complete. The PDC driver uses
> + * threaded IRQs so that response messages are handled outside of interrupt
> + * context.
> + *
> + * The PDC driver allows multiple messages to be pending in the descriptor
> + * rings. The tx_msg_start descriptor index indicates where the last message
> + * starts. The txin_numd value at this index indicates how many descriptor
> + * indexes make up the message. Similar state is kept on the receive side. When
> + * an rx interrupt indicates a response is ready, the PDC driver processes numd
> + * descriptors from the tx and rx ring, thus processing one response at a time.
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/interrupt.h>
> +#include <linux/wait.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox/brcm-message.h>
> +#include <linux/scatterlist.h>
> +#include <linux/dma-direction.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmapool.h>
> +
> +#include "pdc.h"
> +#include "pdc_debug.h"
> +
> +/* Length of BCM header at start of SPU msg, in bytes */
> +#define BCM_HDR_LEN 8
> +
> +/*
> + * PDC driver reserves ringset 0 on each SPU for its own use. The driver does
> + * not currently support use of multiple ringsets on a single PDC engine.
> + */
> +#define PDC_RINGSET 0
> +
> +/*
> + * Interrupt mask and status definitions. Enable interrupts for tx and rx on
> + * ring 0
> + */
> +#define PDC_XMTINT_0 (24 + PDC_RINGSET)
> +#define PDC_RCVINT_0 (16 + PDC_RINGSET)
> +#define PDC_XMTINTEN_0 BIT(PDC_XMTINT_0)
> +#define PDC_RCVINTEN_0 BIT(PDC_RCVINT_0)
> +#define PDC_INTMASK (PDC_XMTINTEN_0 | PDC_RCVINTEN_0)
> +#define PDC_LAZY_FRAMECOUNT 1
> +#define PDC_LAZY_TIMEOUT 10000
> +#define PDC_LAZY_INT (PDC_LAZY_TIMEOUT | (PDC_LAZY_FRAMECOUNT << 24))
> +#define PDC_INTMASK_OFFSET 0x24
> +#define PDC_INTSTATUS_OFFSET 0x20
> +#define PDC_RCVLAZY0_OFFSET (0x30 + 4 * PDC_RINGSET)
> +
> +/*
> + * For SPU2, configure MDE_CKSUM_CONTROL to write 17 bytes of metadata
> + * before frame
> + */
> +#define PDC_SPU2_RESP_HDR_LEN 17
> +#define PDC_CKSUM_CTRL BIT(27)
> +#define PDC_CKSUM_CTRL_OFFSET 0x400
> +
> +#define PDC_SPUM_RESP_HDR_LEN 32
> +
> +/*
> + * Sets the following bits for write to transmit control reg:
> + * 0 - XmtEn - enable activity on the tx channel
> + * 11 - PtyChkDisable - parity check is disabled
> + * 20:18 - BurstLen = 3 -> 2^7 = 128 byte data reads from memory
> + */
> +#define PDC_TX_CTL 0x000C0801
> +
> +/*
> + * Sets the following bits for write to receive control reg:
> + * 0 - RcvEn - enable activity on the rx channel
> + * 7:1 - RcvOffset - size in bytes of status region at start of rx frame buf
> + * 9 - SepRxHdrDescEn - place start of new frames only in descriptors
> + * that have StartOfFrame set
> + * 10 - OflowContinue - on rx FIFO overflow, clear rx fifo, discard all
> + * remaining bytes in current frame, report error
> + * in rx frame status for current frame
> + * 11 - PtyChkDisable - parity check is disabled
> + * 20:18 - BurstLen = 3 -> 2^7 = 128 byte data reads from memory
> + */
> +#define PDC_RX_CTL 0x000C0E01
> +
> +#define CRYPTO_D64_RS0_CD_MASK ((PDC_RING_ENTRIES * RING_ENTRY_SIZE) - 1)
> +
> +/* descriptor flags */
> +#define D64_CTRL1_EOT BIT(28) /* end of descriptor table */
> +#define D64_CTRL1_IOC BIT(29) /* interrupt on complete */
> +#define D64_CTRL1_EOF BIT(30) /* end of frame */
> +#define D64_CTRL1_SOF BIT(31) /* start of frame */
> +
> +#define RX_STATUS_OVERFLOW 0x00800000
> +#define RX_STATUS_LEN 0x0000FFFF
> +
> +#define PDC_TXREGS_OFFSET 0x200
> +#define PDC_RXREGS_OFFSET 0x220
> +
> +/* Maximum size buffer the DMA engine can handle */
> +#define PDC_DMA_BUF_MAX 16384
> +
> +/* Global variables */
> +
> +struct pdc_globals {
> + /* Actual number of SPUs in hardware, as reported by device tree */
> + u32 num_spu;
> +};
> +
> +static struct pdc_globals pdcg;
> +
> +/**
> + * pdc_build_rxd() - Build DMA descriptor to receive SPU result.
> + * @pdcs: PDC state for SPU that will generate result
> + * @dma_addr: DMA address of buffer that descriptor is being built for
> + * @buf_len: Length of the receive buffer, in bytes
> + * @flags: Flags to be stored in descriptor
> + */
> +static inline void
> +pdc_build_rxd(struct pdc_state *pdcs, dma_addr_t dma_addr,
> + u32 buf_len, u32 flags)
> +{
> + struct device *dev = &pdcs->pdev->dev;
> +
> + dev_dbg(dev,
> + "Writing rx descriptor for PDC %u at index %u with length %u. flags %#x\n",
> + pdcs->pdc_idx, pdcs->rxout, buf_len, flags);
> +
> + iowrite32(lower_32_bits(dma_addr),
> + (void *)&pdcs->rxd_64[pdcs->rxout].addrlow);
> + iowrite32(upper_32_bits(dma_addr),
> + (void *)&pdcs->rxd_64[pdcs->rxout].addrhigh);
> + iowrite32(flags, (void *)&pdcs->rxd_64[pdcs->rxout].ctrl1);
> + iowrite32(buf_len, (void *)&pdcs->rxd_64[pdcs->rxout].ctrl2);
> + /* bump ring index and return */
> + pdcs->rxout = NEXTRXD(pdcs->rxout, pdcs->nrxpost);
> +}
> +
> +/**
> + * pdc_build_txd() - Build a DMA descriptor to transmit a SPU request to
> + * hardware.
> + * @pdcs: PDC state for the SPU that will process this request
> + * @dma_addr: DMA address of packet to be transmitted
> + * @buf_len: Length of tx buffer, in bytes
> + * @flags: Flags to be stored in descriptor
> + */
> +static inline void
> +pdc_build_txd(struct pdc_state *pdcs, dma_addr_t dma_addr, u32 buf_len,
> + u32 flags)
> +{
> + struct device *dev = &pdcs->pdev->dev;
> +
> + dev_dbg(dev,
> + "Writing tx descriptor for PDC %u at index %u with length %u, flags %#x\n",
> + pdcs->pdc_idx, pdcs->txout, buf_len, flags);
> +
> + iowrite32(lower_32_bits(dma_addr),
> + (void *)&pdcs->txd_64[pdcs->txout].addrlow);
> + iowrite32(upper_32_bits(dma_addr),
> + (void *)&pdcs->txd_64[pdcs->txout].addrhigh);
> + iowrite32(flags, (void *)&pdcs->txd_64[pdcs->txout].ctrl1);
> + iowrite32(buf_len, (void *)&pdcs->txd_64[pdcs->txout].ctrl2);
> +
> + /* bump ring index and return */
> + pdcs->txout = NEXTTXD(pdcs->txout, pdcs->ntxpost);
> +}
> +
> +/**
> + * pdc_receive() - Receive a response message from a given SPU.
> + * @pdcs: PDC state for the SPU to receive from
> + * @mssg: mailbox message to be returned to client
> + *
> + * When the return code indicates success, the response message is available in
> + * the receive buffers provided prior to submission of the request.
> + *
> + * Input:
> + * pdcs - PDC state structure for the SPU to be polled
> + * mssg - mailbox message to be returned to client. This function sets the
> + * context pointer on the message to help the client associate the
> + * response with a request.
> + *
> + * Return: PDC_SUCCESS if one or more receive descriptors was processed
> + * -EAGAIN indicates that no response message is available
> + * -EIO an error occurred
> + */
> +static int
> +pdc_receive(struct pdc_state *pdcs, struct brcm_message *mssg)
> +{
> + struct device *dev = &pdcs->pdev->dev;
> + u32 len, rx_status;
> + u32 num_frags;
> + int i;
> + u8 *resp_hdr; /* virtual addr of start of resp message DMA header */
> + u32 frags_rdy; /* number of fragments ready to read */
> + u32 rx_idx; /* ring index of start of receive frame */
> + dma_addr_t resp_hdr_daddr;
> +
> + spin_lock(&pdcs->pdc_lock);
> +
> + /*
> + * return if a complete response message is not yet ready.
> + * rxin_numd[rxin] is the number of fragments in the next msg
> + * to read.
> + */
> + frags_rdy = NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr, pdcs->nrxpost);
> + if ((frags_rdy == 0) || (frags_rdy < pdcs->rxin_numd[pdcs->rxin])) {
> + /* See if the hw has written more fragments than we know */
> + pdcs->last_rx_curr =
> + (ioread32((void *)&pdcs->rxregs_64->status0) &
> + CRYPTO_D64_RS0_CD_MASK) / RING_ENTRY_SIZE;
> + frags_rdy = NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr,
> + pdcs->nrxpost);
> + if ((frags_rdy == 0) ||
> + (frags_rdy < pdcs->rxin_numd[pdcs->rxin])) {
> + /* No response ready */
> + spin_unlock(&pdcs->pdc_lock);
> + return -EAGAIN;
> + }
> + /* can't read descriptors/data until write index is read */
> + rmb();
> + }
> +
> + num_frags = pdcs->txin_numd[pdcs->txin];
> + dma_unmap_sg(dev, pdcs->src_sg[pdcs->txin],
> + sg_nents(pdcs->src_sg[pdcs->txin]), DMA_TO_DEVICE);
> +
> + for (i = 0; i < num_frags; i++)
> + pdcs->txin = NEXTTXD(pdcs->txin, pdcs->ntxpost);
> +
> + dev_dbg(dev, "PDC %u reclaimed %d tx descriptors",
> + pdcs->pdc_idx, num_frags);
> +
> + rx_idx = pdcs->rxin;
> + num_frags = pdcs->rxin_numd[rx_idx];
> + /* Return opaque context with result */
> + mssg->ctx = pdcs->rxp_ctx[rx_idx];
> + pdcs->rxp_ctx[rx_idx] = NULL;
> + resp_hdr = pdcs->resp_hdr[rx_idx];
> + resp_hdr_daddr = pdcs->resp_hdr_daddr[rx_idx];
> + dma_unmap_sg(dev, pdcs->dst_sg[rx_idx],
> + sg_nents(pdcs->dst_sg[rx_idx]), DMA_FROM_DEVICE);
> +
> + for (i = 0; i < num_frags; i++)
> + pdcs->rxin = NEXTRXD(pdcs->rxin, pdcs->nrxpost);
> +
> + spin_unlock(&pdcs->pdc_lock);
> +
> + dev_dbg(dev, "PDC %u reclaimed %d rx descriptors",
> + pdcs->pdc_idx, num_frags);
> +
> + dev_dbg(dev,
> + "PDC %u txin %u, txout %u, rxin %u, rxout %u, last_rx_curr %u\n",
> + pdcs->pdc_idx, pdcs->txin, pdcs->txout, pdcs->rxin,
> + pdcs->rxout, pdcs->last_rx_curr);
> +
> + if (pdcs->pdc_resp_hdr_len == PDC_SPUM_RESP_HDR_LEN) {
> + /*
> + * For SPU-M, get length of response msg and rx overflow status.
> + */
> + rx_status = *((u32 *)resp_hdr);
> + len = rx_status & RX_STATUS_LEN;
> + dev_dbg(dev,
> + "SPU response length %u bytes", len);
> + if (unlikely(((rx_status & RX_STATUS_OVERFLOW) || (!len)))) {
> + if (rx_status & RX_STATUS_OVERFLOW) {
> + dev_err_ratelimited(dev,
> + "crypto receive overflow");
> + pdcs->rx_oflow++;
> + } else {
> + dev_info_ratelimited(dev, "crypto rx len = 0");
> + }
> + return -EIO;
> + }
> + }
> +
> + dma_pool_free(pdcs->rx_buf_pool, resp_hdr, resp_hdr_daddr);
> +
> + pdcs->pdc_replies++;
> + /* if we read one or more rx descriptors, claim success */
> + if (num_frags > 0)
> + return PDC_SUCCESS;
> + else
> + return -EIO;
> +}
> +
> +/**
> + * pdc_tx_list_sg_add() - Add the buffers in a scatterlist to the transmit
> + * descriptors for a given SPU. The scatterlist buffers contain the data for a
> + * SPU request message.
> + * @spu_idx: The index of the SPU to submit the request to, [0, max_spu)
> + * @sg: Scatterlist whose buffers contain part of the SPU request
> + *
> + * If a scatterlist buffer is larger than PDC_DMA_BUF_MAX, multiple descriptors
> + * are written for that buffer, each <= PDC_DMA_BUF_MAX byte in length.
> + *
> + * Return: PDC_SUCCESS if successful
> + * < 0 otherwise
> + */
> +static int pdc_tx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
> +{
> + u32 flags = 0;
> + u32 eot;
> + u32 tx_avail;
> +
> + /*
> + * Num descriptors needed. Conservatively assume we need a descriptor
> + * for every entry in sg.
> + */
> + u32 num_desc;
> + u32 desc_w = 0; /* Number of tx descriptors written */
> + u32 bufcnt; /* Number of bytes of buffer pointed to by descriptor */
> + dma_addr_t databufptr; /* DMA address to put in descriptor */
> +
> + num_desc = (u32)sg_nents(sg);
> +
> + /* check whether enough tx descriptors are available */
> + tx_avail = pdcs->ntxpost - NTXDACTIVE(pdcs->txin, pdcs->txout,
> + pdcs->ntxpost);
> + if (unlikely(num_desc > tx_avail)) {
> + pdcs->txnobuf++;
> + return -ENOSPC;
> + }
> +
> + /* build tx descriptors */
> + if (pdcs->tx_msg_start == pdcs->txout) {
> + /* Start of frame */
> + pdcs->txin_numd[pdcs->tx_msg_start] = 0;
> + pdcs->src_sg[pdcs->txout] = sg;
> + flags = D64_CTRL1_SOF;
> + }
> +
> + while (sg) {
> + if (unlikely(pdcs->txout == (pdcs->ntxd - 1)))
> + eot = D64_CTRL1_EOT;
> + else
> + eot = 0;
> +
> + /*
> + * If sg buffer larger than PDC limit, split across
> + * multiple descriptors
> + */
> + bufcnt = sg_dma_len(sg);
> + databufptr = sg_dma_address(sg);
> + while (bufcnt > PDC_DMA_BUF_MAX) {
> + pdc_build_txd(pdcs, databufptr, PDC_DMA_BUF_MAX,
> + flags | eot);
> + desc_w++;
> + bufcnt -= PDC_DMA_BUF_MAX;
> + databufptr += PDC_DMA_BUF_MAX;
> + if (unlikely(pdcs->txout == (pdcs->ntxd - 1)))
> + eot = D64_CTRL1_EOT;
> + else
> + eot = 0;
> + }
> + sg = sg_next(sg);
> + if (!sg)
> + /* Writing last descriptor for frame */
> + flags |= (D64_CTRL1_EOF | D64_CTRL1_IOC);
> + pdc_build_txd(pdcs, databufptr, bufcnt, flags | eot);
> + desc_w++;
> + /* Clear start of frame after first descriptor */
> + flags &= ~D64_CTRL1_SOF;
> + }
> + pdcs->txin_numd[pdcs->tx_msg_start] += desc_w;
> +
> + return PDC_SUCCESS;
> +}
> +
> +/**
> + * pdc_tx_list_final() - Initiate DMA transfer of last frame written to tx
> + * ring.
> + * @pdcs: PDC state for SPU to process the request
> + *
> + * Sets the index of the last descriptor written in both the rx and tx ring.
> + *
> + * Return: PDC_SUCCESS
> + */
> +static int pdc_tx_list_final(struct pdc_state *pdcs)
> +{
> + /*
> + * write barrier to ensure all register writes are complete
> + * before chip starts to process new request
> + */
> + wmb();
> + iowrite32(pdcs->rxout << 4, (void *)&pdcs->rxregs_64->ptr);
> + iowrite32(pdcs->txout << 4, (void *)&pdcs->txregs_64->ptr);
> + pdcs->pdc_requests++;
> +
> + return PDC_SUCCESS;
> +}
> +
> +/**
> + * pdc_rx_list_init() - Start a new receive descriptor list for a given PDC.
> + * @pdcs: PDC state for SPU handling request
> + * @dst_sg: scatterlist providing rx buffers for response to be returned to
> + * mailbox client
> + * @ctx: Opaque context for this request
> + *
> + * Posts a single receive descriptor to hold the metadata that precedes a
> + * response. For example, with SPU-M, the metadata is a 32-byte DMA header and
> + * an 8-byte BCM header. Moves the msg_start descriptor indexes for both tx and
> + * rx to indicate the start of a new message.
> + *
> + * Return: PDC_SUCCESS if successful
> + * < 0 if an error (e.g., rx ring is full)
> + */
> +static int pdc_rx_list_init(struct pdc_state *pdcs, struct scatterlist *dst_sg,
> + void *ctx)
> +{
> + u32 flags = 0;
> + u32 rx_avail;
> + u32 rx_pkt_cnt = 1; /* Adding a single rx buffer */
> + dma_addr_t daddr;
> + void *vaddr;
> +
> + rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
> + pdcs->nrxpost);
> + if (unlikely(rx_pkt_cnt > rx_avail)) {
> + pdcs->rxnobuf++;
> + return -ENOSPC;
> + }
> +
> + /* allocate a buffer for the dma rx status */
> + vaddr = dma_pool_zalloc(pdcs->rx_buf_pool, GFP_ATOMIC, &daddr);
> + if (!vaddr)
> + return -ENOMEM;
> +
> + /*
> + * Update msg_start indexes for both tx and rx to indicate the start
> + * of a new sequence of descriptor indexes that contain the fragments
> + * of the same message.
> + */
> + pdcs->rx_msg_start = pdcs->rxout;
> + pdcs->tx_msg_start = pdcs->txout;
> +
> + /* This is always the first descriptor in the receive sequence */
> + flags = D64_CTRL1_SOF;
> + pdcs->rxin_numd[pdcs->rx_msg_start] = 1;
> +
> + if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
> + flags |= D64_CTRL1_EOT;
> +
> + pdcs->rxp_ctx[pdcs->rxout] = ctx;
> + pdcs->dst_sg[pdcs->rxout] = dst_sg;
> + pdcs->resp_hdr[pdcs->rxout] = vaddr;
> + pdcs->resp_hdr_daddr[pdcs->rxout] = daddr;
> + pdc_build_rxd(pdcs, daddr, pdcs->pdc_resp_hdr_len, flags);
> + return PDC_SUCCESS;
> +}
> +
> +/**
> + * pdc_rx_list_sg_add() - Add the buffers in a scatterlist to the receive
> + * descriptors for a given SPU. The caller must have already DMA mapped the
> + * scatterlist.
> + * @spu_idx: Indicates which SPU the buffers are for
> + * @sg: Scatterlist whose buffers are added to the receive ring
> + *
> + * If a receive buffer in the scatterlist is larger than PDC_DMA_BUF_MAX,
> + * multiple receive descriptors are written, each with a buffer <=
> + * PDC_DMA_BUF_MAX.
> + *
> + * Return: PDC_SUCCESS if successful
> + * < 0 otherwise (e.g., receive ring is full)
> + */
> +static int pdc_rx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
> +{
> + u32 flags = 0;
> + u32 rx_avail;
> +
> + /*
> + * Num descriptors needed. Conservatively assume we need a descriptor
> + * for every entry from our starting point in the scatterlist.
> + */
> + u32 num_desc;
> + u32 desc_w = 0; /* Number of tx descriptors written */
> + u32 bufcnt; /* Number of bytes of buffer pointed to by descriptor */
> + dma_addr_t databufptr; /* DMA address to put in descriptor */
> +
> + num_desc = (u32)sg_nents(sg);
> +
> + rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
> + pdcs->nrxpost);
> + if (unlikely(num_desc > rx_avail)) {
> + pdcs->rxnobuf++;
> + return -ENOSPC;
> + }
> +
> + while (sg) {
> + if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
> + flags = D64_CTRL1_EOT;
> + else
> + flags = 0;
> +
> + /*
> + * If sg buffer larger than PDC limit, split across
> + * multiple descriptors
> + */
> + bufcnt = sg_dma_len(sg);
> + databufptr = sg_dma_address(sg);
> + while (bufcnt > PDC_DMA_BUF_MAX) {
> + pdc_build_rxd(pdcs, databufptr, PDC_DMA_BUF_MAX, flags);
> + desc_w++;
> + bufcnt -= PDC_DMA_BUF_MAX;
> + databufptr += PDC_DMA_BUF_MAX;
> + if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
> + flags = D64_CTRL1_EOT;
> + else
> + flags = 0;
> + }
> + pdc_build_rxd(pdcs, databufptr, bufcnt, flags);
> + desc_w++;
> + sg = sg_next(sg);
> + }
> + pdcs->rxin_numd[pdcs->rx_msg_start] += desc_w;
> +
> + return PDC_SUCCESS;
> +}
> +
> +/**
> + * pdc_irq_handler() - Interrupt handler called in interrupt context.
> + * @irq: Interrupt number that has fired
> + * @cookie: PDC state for DMA engine that generated the interrupt
> + *
> + * We have to clear the device interrupt status flags here. So cache the
> + * status for later use in the thread function. Other than that, just return
> + * WAKE_THREAD to invoke the thread function.
> + *
> + * Return: IRQ_WAKE_THREAD if interrupt is ours
> + * IRQ_NONE otherwise
> + */
> +static irqreturn_t pdc_irq_handler(int irq, void *cookie)
> +{
> + struct pdc_state *pdcs = cookie;
> + u32 intstatus = ioread32(pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
> +
> + if (intstatus & PDC_XMTINTEN_0)
> + set_bit(PDC_XMTINT_0, &pdcs->intstatus);
> + if (intstatus & PDC_RCVINTEN_0)
> + set_bit(PDC_RCVINT_0, &pdcs->intstatus);
> +
> + /* Clear interrupt flags in device */
> + iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
> +
> + /* Wakeup IRQ thread */
> + if (pdcs && (irq == pdcs->pdc_irq) && (intstatus & PDC_INTMASK))
> + return IRQ_WAKE_THREAD;
> +
> + return IRQ_NONE;
> +}
> +
> +/**
> + * pdc_irq_thread() - Function invoked on deferred thread when a DMA tx has
> + * completed or data is available to receive.
> + * @irq: Interrupt number
> + * @cookie: PDC state for PDC that generated the interrupt
> + *
> + * On DMA tx complete, notify the mailbox client. On DMA rx complete, process
> + * as many SPU response messages as are available and send each to the mailbox
> + * client.
> + *
> + * Return: IRQ_HANDLED if we recognized and handled the interrupt
> + * IRQ_NONE otherwise
> + */
> +static irqreturn_t pdc_irq_thread(int irq, void *cookie)
> +{
> + struct pdc_state *pdcs = cookie;
> + struct mbox_controller *mbc;
> + struct mbox_chan *chan;
> + bool tx_int;
> + bool rx_int;
> + int rx_status;
> + struct brcm_message mssg;
> +
> + tx_int = test_and_clear_bit(PDC_XMTINT_0, &pdcs->intstatus);
> + rx_int = test_and_clear_bit(PDC_RCVINT_0, &pdcs->intstatus);
> +
> + if (pdcs && (tx_int || rx_int)) {
> + dev_dbg(&pdcs->pdev->dev,
> + "%s() got irq %d with tx_int %s, rx_int %s",
> + __func__, irq,
> + tx_int ? "set" : "clear", rx_int ? "set" : "clear");
> +
> + mbc = &pdcs->mbc;
> + chan = &mbc->chans[0];
> +
> + if (tx_int) {
> + dev_dbg(&pdcs->pdev->dev, "%s(): tx done", __func__);
> + /* only one frame in flight at a time */
> + mbox_chan_txdone(chan, PDC_SUCCESS);
> + }
> + if (rx_int) {
> + while (1) {
> + /* Could be many frames ready */
> + memset(&mssg, 0, sizeof(mssg));
> + mssg.type = BRCM_MESSAGE_SPU;
> + rx_status = pdc_receive(pdcs, &mssg);
> + if (rx_status >= 0) {
> + dev_dbg(&pdcs->pdev->dev,
> + "%s(): invoking client rx cb",
> + __func__);
> + mbox_chan_received_data(chan, &mssg);
> + } else {
> + dev_dbg(&pdcs->pdev->dev,
> + "%s(): no SPU response available",
> + __func__);
> + break;
> + }
> + }
> + }
> + return IRQ_HANDLED;
> + }
> + return IRQ_NONE;
> +}
> +
> +/**
> + * pdc_ring_init() - Allocate DMA rings and initialize constant fields of
> + * descriptors in one ringset.
> + * @pdcs: PDC instance state
> + * @ringset: index of ringset being used
> + *
> + * Return: PDC_SUCCESS if ring initialized
> + * < 0 otherwise
> + */
> +static int pdc_ring_init(struct pdc_state *pdcs, int ringset)
> +{
> + int i;
> + int err = PDC_SUCCESS;
> + struct dma64 *dma_reg;
> + struct device *dev = &pdcs->pdev->dev;
> + struct pdc_ring_alloc tx;
> + struct pdc_ring_alloc rx;
> +
> + /* Allocate tx ring */
> + tx.vbase = dma_pool_zalloc(pdcs->ring_pool, GFP_KERNEL, &tx.dmabase);
> + if (!tx.vbase) {
> + err = -ENOMEM;
> + goto done;
> + }
> +
> + /* Allocate rx ring */
> + rx.vbase = dma_pool_zalloc(pdcs->ring_pool, GFP_KERNEL, &rx.dmabase);
> + if (!rx.vbase) {
> + err = -ENOMEM;
> + goto fail_dealloc;
> + }
> +
> + dev_dbg(dev, " - base DMA addr of tx ring %#llx", tx.dmabase);
> + dev_dbg(dev, " - base virtual addr of tx ring %p", tx.vbase);
> + dev_dbg(dev, " - base DMA addr of rx ring %#llx", rx.dmabase);
> + dev_dbg(dev, " - base virtual addr of rx ring %p", rx.vbase);
> +
> + /* lock after ring allocation to avoid scheduling while atomic */
> + spin_lock(&pdcs->pdc_lock);
> +
> + memcpy(&pdcs->tx_ring_alloc, &tx, sizeof(tx));
> + memcpy(&pdcs->rx_ring_alloc, &rx, sizeof(rx));
> +
> + pdcs->rxin = 0;
> + pdcs->rx_msg_start = 0;
> + pdcs->last_rx_curr = 0;
> + pdcs->rxout = 0;
> + pdcs->txin = 0;
> + pdcs->tx_msg_start = 0;
> + pdcs->txout = 0;
> +
> + /* Set descriptor array base addresses */
> + pdcs->txd_64 = (struct dma64dd *)pdcs->tx_ring_alloc.vbase;
> + pdcs->rxd_64 = (struct dma64dd *)pdcs->rx_ring_alloc.vbase;
> +
> + /* Tell device the base DMA address of each ring */
> + dma_reg = &pdcs->regs->dmaregs[ringset];
> + iowrite32(lower_32_bits(pdcs->tx_ring_alloc.dmabase),
> + (void *)&dma_reg->dmaxmt.addrlow);
> + iowrite32(upper_32_bits(pdcs->tx_ring_alloc.dmabase),
> + (void *)&dma_reg->dmaxmt.addrhigh);
> +
> + iowrite32(lower_32_bits(pdcs->rx_ring_alloc.dmabase),
> + (void *)&dma_reg->dmarcv.addrlow);
> + iowrite32(upper_32_bits(pdcs->rx_ring_alloc.dmabase),
> + (void *)&dma_reg->dmarcv.addrhigh);
> +
> + /* Initialize descriptors */
> + for (i = 0; i < PDC_RING_ENTRIES; i++) {
> + /* Every tx descriptor can be used for start of frame. */
> + if (i != pdcs->ntxpost) {
> + iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOF,
> + (void *)&pdcs->txd_64[i].ctrl1);
> + } else {
> + /* Last descriptor in ringset. Set End of Table. */
> + iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOF |
> + D64_CTRL1_EOT,
> + (void *)&pdcs->txd_64[i].ctrl1);
> + }
> +
> + /* Every rx descriptor can be used for start of frame */
> + if (i != pdcs->nrxpost) {
> + iowrite32(D64_CTRL1_SOF,
> + (void *)&pdcs->rxd_64[i].ctrl1);
> + } else {
> + /* Last descriptor in ringset. Set End of Table. */
> + iowrite32(D64_CTRL1_SOF | D64_CTRL1_EOT,
> + (void *)&pdcs->rxd_64[i].ctrl1);
> + }
> + }
> + spin_unlock(&pdcs->pdc_lock);
> + return PDC_SUCCESS;
> +
> +fail_dealloc:
> + dma_pool_free(pdcs->ring_pool, tx.vbase, tx.dmabase);
> +done:
> + return err;
> +}
> +
> +static void pdc_ring_free(struct pdc_state *pdcs)
> +{
> + if (pdcs->tx_ring_alloc.vbase) {
> + dma_pool_free(pdcs->ring_pool, pdcs->tx_ring_alloc.vbase,
> + pdcs->tx_ring_alloc.dmabase);
> + pdcs->tx_ring_alloc.vbase = NULL;
> + }
> +
> + if (pdcs->rx_ring_alloc.vbase) {
> + dma_pool_free(pdcs->ring_pool, pdcs->rx_ring_alloc.vbase,
> + pdcs->rx_ring_alloc.dmabase);
> + pdcs->rx_ring_alloc.vbase = NULL;
> + }
> +}
> +
> +/**
> + * pdc_send_data() - mailbox send_data function
> + * @chan: The mailbox channel on which the data is sent. The channel
> + * corresponds to a DMA ringset.
> + * @data: The mailbox message to be sent. The message must be a
> + * brcm_message structure.
> + *
> + * This function is registered as the send_data function for the mailbox
> + * controller. From the destination scatterlist in the mailbox message, it
> + * creates a sequence of receive descriptors in the rx ring. From the source
> + * scatterlist, it creates a sequence of transmit descriptors in the tx ring.
> + * After creating the descriptors, it writes the rx ptr and tx ptr registers to
> + * initiate the DMA transfer.
> + *
> + * This function does the DMA map and unmap of the src and dst scatterlists in
> + * the mailbox message.
> + *
> + * Return: 0 if successful
> + * -ENOTSUPP if the mailbox message is a type this driver does not
> + * support
> + * < 0 if an error
> + */
> +static int pdc_send_data(struct mbox_chan *chan, void *data)
> +{
> + struct pdc_state *pdcs = chan->con_priv;
> + struct device *dev = &pdcs->pdev->dev;
> + struct brcm_message *mssg = data;
> + int err = PDC_SUCCESS;
> + int src_nent;
> + int dst_nent;
> + int nent;
> +
> + if (mssg->type != BRCM_MESSAGE_SPU)
> + return -ENOTSUPP;
> +
> + src_nent = sg_nents(mssg->spu.src);
> + if (src_nent) {
> + nent = dma_map_sg(dev, mssg->spu.src, src_nent, DMA_TO_DEVICE);
> + if (nent == 0)
> + return -EIO;
> + }
> +
> + dst_nent = sg_nents(mssg->spu.dst);
> + if (dst_nent) {
> + nent = dma_map_sg(dev, mssg->spu.dst, dst_nent,
> + DMA_FROM_DEVICE);
> + if (nent == 0) {
> + dma_unmap_sg(dev, mssg->spu.src, src_nent,
> + DMA_TO_DEVICE);
> + return -EIO;
> + }
> + }
> +
> + spin_lock(&pdcs->pdc_lock);
> +
> + /* Create rx descriptors to SPU catch response */
> + err = pdc_rx_list_init(pdcs, mssg->spu.dst, mssg->ctx);
> + err |= pdc_rx_list_sg_add(pdcs, mssg->spu.dst);
> +
> + /* Create tx descriptors to submit SPU request */
> + err |= pdc_tx_list_sg_add(pdcs, mssg->spu.src);
> + err |= pdc_tx_list_final(pdcs); /* initiate transfer */
> +
> + spin_unlock(&pdcs->pdc_lock);
> +
> + if (err)
> + dev_err(&pdcs->pdev->dev,
> + "%s failed with error %d", __func__, err);
> +
> + return err;
> +}
> +
> +static int pdc_startup(struct mbox_chan *chan)
> +{
> + return pdc_ring_init(chan->con_priv, PDC_RINGSET);
> +}
> +
> +static void pdc_shutdown(struct mbox_chan *chan)
> +{
> + struct pdc_state *pdcs = chan->con_priv;
> +
> + if (pdcs)
> + dev_dbg(&pdcs->pdev->dev,
> + "Shutdown mailbox channel for PDC %u", pdcs->pdc_idx);
> +
> + pdc_ring_free(pdcs);
> +}
> +
> +/**
> + * pdc_hw_init() - Use the given initialization parameters to initialize the
> + * state for one of the PDCs.
> + * @dev: device structure for PDC
> + * @pdcs: state of the PDC
> + * @parms: parameter values to set
> + */
> +static
> +void pdc_hw_init(struct device *dev, struct pdc_state *pdcs,
> + struct hw_init_parms *parms)
>
You could do without the dev and parms.

> +{
> + struct dma64 *dma_reg;
> +
> + int ringset = PDC_RINGSET;
> +
> + dev_dbg(dev, "PDC %u initial values:", pdcs->pdc_idx);
> + dev_dbg(dev, "state structure: %p",
> + pdcs);
> + dev_dbg(dev, " - base physical addr of hw regs %#llx",
> + parms->hw_pbase);
> + dev_dbg(dev, " - base virtual addr of hw regs %p",
> + parms->hw_vbase);
> +
> + /* initialize data structures */
> + pdcs->regs = (struct pdc_regs *)parms->hw_vbase;
> + pdcs->txregs_64 = (struct dma64_regs *)
> + (void *)(((u8 *)parms->hw_vbase) +
> + PDC_TXREGS_OFFSET + (sizeof(struct dma64) * ringset));
> + pdcs->rxregs_64 = (struct dma64_regs *)
> + (void *)(((u8 *)parms->hw_vbase) +
> + PDC_RXREGS_OFFSET + (sizeof(struct dma64) * ringset));
> +
> + pdcs->ntxd = parms->ring_entries;
> + pdcs->nrxd = parms->ring_entries;
> + pdcs->ntxpost = parms->ring_entries - 1;
> + pdcs->nrxpost = parms->ring_entries - 1;
> + pdcs->regs->intmask = 0;
> +
> + dma_reg = &pdcs->regs->dmaregs[ringset];
> + iowrite32(0, (void *)&dma_reg->dmaxmt.ptr);
> + iowrite32(0, (void *)&dma_reg->dmarcv.ptr);
> +
> + iowrite32(PDC_TX_CTL, (void *)&dma_reg->dmaxmt.control);
> +
> + iowrite32(PDC_RX_CTL + (pdcs->rx_status_len << 1),
> + (void *)&dma_reg->dmarcv.control);
> +
> + if (pdcs->pdc_resp_hdr_len == PDC_SPU2_RESP_HDR_LEN)
> + iowrite32(PDC_CKSUM_CTRL,
> + pdcs->pdc_reg_vbase + PDC_CKSUM_CTRL_OFFSET);
> +}
> +
> +/**
> + * pdc_rx_buf_pool_create() - Pool of receive buffers used to catch the metadata
> + * header returned with each response message.
> + * @dev: device structure
> + * @pdcs: PDC state structure
> + *
> + * The metadata is not returned to the mailbox client. So the PDC driver
> + * manages these buffers.
> + *
> + * Return: PDC_SUCCESS
> + * -ENOMEM if pool creation fails
> + */
> +static int pdc_rx_buf_pool_create(struct device *dev, struct pdc_state *pdcs)
> +{
> + pdcs->pdc_resp_hdr_len = pdcs->rx_status_len;
> + if (pdcs->use_bcm_hdr)
> + pdcs->pdc_resp_hdr_len += BCM_HDR_LEN;
> +
> + pdcs->rx_buf_pool = dma_pool_create("pdc rx bufs", dev,
> + pdcs->pdc_resp_hdr_len,
> + RX_BUF_ALIGN, 0);
> + if (!pdcs->rx_buf_pool)
> + return -ENOMEM;
> +
> + return PDC_SUCCESS;
> +}
> +
> +/**
> + * pdc_interrupts_init() - Initialize the interrupt configuration for a PDC and
> + * specify a threaded IRQ handler for deferred handling of interrupts outside of
> + * interrupt context.
> + * @pdev: platform device
> + * @pdcs: PDC state
> + *
> + * Set the interrupt mask for transmit and receive done.
> + * Set the lazy interrupt frame count to generate an interrupt for just one pkt.
> + *
> + * Return: PDC_SUCCESS
> + * <0 if threaded irq request fails
> + */
> +static int pdc_interrupts_init(struct platform_device *pdev,
> + struct pdc_state *pdcs)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *dn = pdev->dev.of_node;
> + int err;
> +
> + pdcs->intstatus = 0;
> +
> + /* interrupt configuration */
> + iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
> + iowrite32(PDC_LAZY_INT, pdcs->pdc_reg_vbase + PDC_RCVLAZY0_OFFSET);
> +
> + /* read irq from device tree */
> + pdcs->pdc_irq = irq_of_parse_and_map(dn, 0);
> + dev_dbg(dev, "pdc device %s irq %u for pdcs %p",
> + dev_name(dev), pdcs->pdc_irq, pdcs);
> + err = devm_request_threaded_irq(dev, pdcs->pdc_irq,
> + pdc_irq_handler,
> + pdc_irq_thread, 0, dev_name(dev), pdcs);
> + if (err) {
> + dev_err(dev, "threaded tx IRQ %u request failed with err %d\n",
> + pdcs->pdc_irq, err);
> + return err;
> + }
> + return PDC_SUCCESS;
> +}
> +
> +static const struct mbox_chan_ops pdc_mbox_chan_ops = {
> + .send_data = pdc_send_data,
> + .startup = pdc_startup,
> + .shutdown = pdc_shutdown
> +};
> +
> +/**
> + * pdc_mb_init() - Initialize the mailbox controller.
> + * @pdcs: PDC state
> + *
> + * Each PDC is a mailbox controller. Each ringset is a mailbox channel. Kernel
> + * driver only uses one ringset and thus one mb channel. PDC uses the transmit
> + * complete interrupt to determine when a mailbox message has successfully been
> + * transmitted.
> + *
> + * Return: 0 on success
> + * < 0 if there is an allocation or registration failure
> + */
> +static int pdc_mb_init(struct pdc_state *pdcs)
> +{
> + struct device *dev = &pdcs->pdev->dev;
> + struct mbox_controller *mbc;
> + int chan_index;
> + int err;
> +
> + mbc = &pdcs->mbc;
> + mbc->dev = dev;
> + mbc->ops = &pdc_mbox_chan_ops;
> + mbc->num_chans = 1;
> + mbc->chans = devm_kcalloc(dev, mbc->num_chans, sizeof(*mbc->chans),
> + GFP_KERNEL);
> + if (!mbc->chans)
> + return -ENOMEM;
> +
> + mbc->txdone_irq = true;
> + mbc->txdone_poll = false;
> + for (chan_index = 0; chan_index < mbc->num_chans; chan_index++)
> + mbc->chans[chan_index].con_priv = pdcs;
> +
> + /* Register mailbox controller */
> + err = mbox_controller_register(mbc);
> + if (err) {
> + dev_crit(dev,
> + "Failed to register PDC mailbox controller. Error %d.",
> + err);
> + return err;
> + }
> + return 0;
> +}
> +
> +/**
> + * pdc_dt_read() - Read application-specific data from device tree.
> + * @pdev: Platform device
> + * @pdcs: PDC state
> + *
> + * Reads the number of bytes of receive status that precede each received frame.
> + * Reads whether transmit and received frames should be preceded by an 8-byte
> + * BCM header.
> + *
> + * Return: 0 if successful
> + * -ENODEV if device not available
> + */
> +static int pdc_dt_read(struct platform_device *pdev, struct pdc_state *pdcs)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *dn = pdev->dev.of_node;
> + int err;
> +
> + err = of_property_read_u32(dn, "brcm,rx-status-len",
> + &pdcs->rx_status_len);
> + if (err < 0)
> + dev_err(dev,
> + "%s failed to get DMA receive status length from device tree",
> + __func__);
> +
> + pdcs->use_bcm_hdr = of_property_read_bool(dn, "brcm,use-bcm-hdr");
> +
> + return 0;
> +}
> +
> +/**
> + * pdc_probe() - Probe function for PDC driver.
> + * @pdev: PDC platform device
> + *
> + * Reserve and map register regions defined in device tree.
> + * Allocate and initialize tx and rx DMA rings.
> + * Initialize a mailbox controller for each PDC.
> + *
> + * Return: 0 if successful
> + * < 0 if an error
> + */
> +static int pdc_probe(struct platform_device *pdev)
> +{
> + int err = 0;
> + struct device *dev = &pdev->dev;
> + struct resource *pdc_regs;
> + struct pdc_state *pdcs;
> + struct hw_init_parms hw_parms; /* params for initializing spu-dma */
> +
> + /* PDC state for one SPU */
> + pdcs = devm_kzalloc(dev, sizeof(*pdcs), GFP_KERNEL);
> + if (!pdcs) {
> + err = -ENOMEM;
> + goto cleanup;
> + }
> +
> + spin_lock_init(&pdcs->pdc_lock);
> + pdcs->pdev = pdev;
> + platform_set_drvdata(pdev, pdcs);
> + pdcs->pdc_idx = pdcg.num_spu;
> + pdcg.num_spu++;
> +
> + err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> + if (err) {
> + dev_warn(dev, "PDC device cannot perform DMA. Error %d.", err);
> + goto cleanup;
> + }
> +
> + /* Create DMA pool for tx ring */
> + pdcs->ring_pool = dma_pool_create("pdc rings", dev, PDC_RING_SIZE,
> + RING_ALIGN, 0);
> + if (!pdcs->ring_pool) {
> + err = -ENOMEM;
> + goto cleanup;
> + }
> +
> + err = pdc_dt_read(pdev, pdcs);
> + if (err)
> + goto cleanup_ring_pool;
> +
> + pdc_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!pdc_regs) {
> + err = -ENODEV;
> + goto cleanup_ring_pool;
> + }
> + dev_dbg(dev, "PDC register region res.start = %#llx, res.end = %#llx",
> + pdc_regs->start, pdc_regs->end);
> +
> + pdcs->pdc_reg_vbase = devm_ioremap_resource(&pdev->dev, pdc_regs);
> + if (IS_ERR(pdcs->pdc_reg_vbase)) {
> + err = PTR_ERR(pdcs->pdc_reg_vbase);
> + dev_err(&pdev->dev, "Failed to map registers: %d\n", err);
> + goto cleanup_ring_pool;
> + }
> +
> + /* create rx buffer pool after dt read to know how big buffers are */
> + err = pdc_rx_buf_pool_create(dev, pdcs);
'dev' argument could be omitted.

> + if (err)
> + goto cleanup_ring_pool;
> +
> + hw_parms.hw_pbase = (dma_addr_t)(pdc_regs->start);
> + hw_parms.hw_vbase = pdcs->pdc_reg_vbase;
> +
> + hw_parms.ring_entries = PDC_RING_ENTRIES;
> +
> + pdc_hw_init(dev, pdcs, &hw_parms);
'dev' and 'hw_parms' argument could be omitted.

> +
> + err = pdc_interrupts_init(pdev, pdcs);
'pdev' argument could be omitted.

thanks.