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

Rob Rice
2016-06-28T13:36:59Z

Jassi,

Thanks for the comments. Replies below.

Rob

On Sun, Jun 26, 2016 at 2:31 AM, Jassi Brar <jassisinghbrar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> 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?

[WRR] I'm using debugfs to display stats, not so much for testing the
module. So I don't think mailbox-test is a substitute. But if you
prefer, I'll move the stats code into pdc.c, along with the code from
pdc.h and move pdc.c from the mailbox-pdc directory up to
drivers/mailbox.

>
>> 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.

[WRR] Yes, I can get dev from pdcs. but parms is a stack variable in
the calling function and has to be passed, as I see it.

>
>> +{
>> + 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.

[WRR] Yes, I can do that.

>
>> + 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.

[WRR] Removed dev.

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

[WRR] OK.

>
>
> thanks.