RE: [EXT] Re: [V3 2/2] dmaengine: fsl-dpaa2-qdma: Add NXP dpaa2 qDMA controller driver for Layerscape SoCs

[Peng Ma]

Hi, Vinod,

Please see my comments inline, thanks very much.

Best Regards,
Peng

>-----Original Message-----
>From: Vinod Koul <vkoul@xxxxxxxxxx>
>Sent: 2019年4月29日 13:32
>To: Peng Ma <peng.ma@xxxxxxx>
>Cc: dan.j.williams@xxxxxxxxx; Leo Li <leoyang.li@xxxxxxx>;
>linux-kernel@xxxxxxxxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx
>Subject: [EXT] Re: [V3 2/2] dmaengine: fsl-dpaa2-qdma: Add NXP dpaa2 qDMA
>controller driver for Layerscape SoCs
>
>Caution: EXT Email
>
>On 09-04-19, 15:22, Peng Ma wrote:
>> DPPA2(Data Path Acceleration Architecture 2) qDMA The qDMA supports
>> channel virtualization by allowing DMA jobs to be enqueued into
>> different frame queues. Core can initiate a DMA transaction by
>> preparing a frame descriptor(FD) for each DMA job and enqueuing this job to
>a frame queue.
>> through a hardware portal. The qDMA prefetches DMA jobs from the frame
>queues.
>> It then schedules and dispatches to internal DMA hardware engines,
>> which generate read and write requests. Both qDMA source data and
>> destination data can be either contiguous or non-contiguous using one or
>more scatter/gather tables.
>> The qDMA supports global bandwidth flow control where all DMA
>> transactions are stalled if the bandwidth threshold has been reached.
>> Also supported are transaction based read throttling.
>>
>> Add NXP dppa2 qDMA to support some of Layerscape SoCs.
>> such as: LS1088A, LS208xA, LX2, etc.
>>
>> Signed-off-by: Peng Ma <peng.ma@xxxxxxx>
>> ---
>> changed for v3:
>>       - Add depends on arm64 for dpaa2 qdma driver
>>       - The dpaa2_io_service_[de]register functions have a new
>parameter
>>       So update all calls to some functions
>>
>>  drivers/dma/Kconfig                     |    2 +
>>  drivers/dma/Makefile                    |    1 +
>>  drivers/dma/fsl-dpaa2-qdma/Kconfig      |    9 +
>>  drivers/dma/fsl-dpaa2-qdma/Makefile     |    3 +
>>  drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.c |  782
>> +++++++++++++++++++++++++++++++
>> drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.h |  152 ++++++
>>  6 files changed, 949 insertions(+), 0 deletions(-)  create mode
>> 100644 drivers/dma/fsl-dpaa2-qdma/Kconfig
>>  create mode 100644 drivers/dma/fsl-dpaa2-qdma/Makefile
>>  create mode 100644 drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.c
>>  create mode 100644 drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.h
>>
>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig index
>> eaf78f4..08aae01 100644
>> --- a/drivers/dma/Kconfig
>> +++ b/drivers/dma/Kconfig
>> @@ -671,6 +671,8 @@ source "drivers/dma/sh/Kconfig"
>>
>>  source "drivers/dma/ti/Kconfig"
>>
>> +source "drivers/dma/fsl-dpaa2-qdma/Kconfig"
>> +
>>  # clients
>>  comment "DMA Clients"
>>       depends on DMA_ENGINE
>> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile index
>> 6126e1c..2499ed8 100644
>> --- a/drivers/dma/Makefile
>> +++ b/drivers/dma/Makefile
>> @@ -75,6 +75,7 @@ obj-$(CONFIG_UNIPHIER_MDMAC) +=
>uniphier-mdmac.o
>>  obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
>>  obj-$(CONFIG_ZX_DMA) += zx_dma.o
>>  obj-$(CONFIG_ST_FDMA) += st_fdma.o
>> +obj-$(CONFIG_FSL_DPAA2_QDMA) += fsl-dpaa2-qdma/
>>
>>  obj-y += mediatek/
>>  obj-y += qcom/
>> diff --git a/drivers/dma/fsl-dpaa2-qdma/Kconfig
>> b/drivers/dma/fsl-dpaa2-qdma/Kconfig
>> new file mode 100644
>> index 0000000..258ed6b
>> --- /dev/null
>> +++ b/drivers/dma/fsl-dpaa2-qdma/Kconfig
>> @@ -0,0 +1,9 @@
>> +menuconfig FSL_DPAA2_QDMA
>> +     tristate "NXP DPAA2 QDMA"
>> +     depends on ARM64
>> +     depends on FSL_MC_BUS && FSL_MC_DPIO
>> +     select DMA_ENGINE
>> +     select DMA_VIRTUAL_CHANNELS
>> +     help
>> +       NXP Data Path Acceleration Architecture 2 QDMA driver,
>> +       using the NXP MC bus driver.
>> diff --git a/drivers/dma/fsl-dpaa2-qdma/Makefile
>> b/drivers/dma/fsl-dpaa2-qdma/Makefile
>> new file mode 100644
>> index 0000000..c1d0226
>> --- /dev/null
>> +++ b/drivers/dma/fsl-dpaa2-qdma/Makefile
>> @@ -0,0 +1,3 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Makefile for the NXP DPAA2 qDMA controllers
>> +obj-$(CONFIG_FSL_DPAA2_QDMA) += dpaa2-qdma.o dpdmai.o
>> diff --git a/drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.c
>> b/drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.c
>> new file mode 100644
>> index 0000000..0cdde0f
>> --- /dev/null
>> +++ b/drivers/dma/fsl-dpaa2-qdma/dpaa2-qdma.c
>> @@ -0,0 +1,782 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright 2014-2018 NXP
>> +
>> +/*
>> + * Author: Changming Huang <jerry.huang@xxxxxxx>
>> + *
>> + * Driver for the NXP QDMA engine with QMan mode.
>> + * Channel virtualization is supported through enqueuing of DMA jobs
>> +to,
>> + * or dequeuing DMA jobs from different work queues with QMan portal.
>> + * This module can be found on NXP LS2 SoCs.
>> + *
>> + */
>> +
>> +#include <linux/init.h>
>> +#include <linux/module.h>
>> +#include <linux/dmapool.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/iommu.h>
>> +#include <linux/sys_soc.h>
>> +#include <linux/fsl/mc.h>
>> +#include <soc/fsl/dpaa2-io.h>
>> +
>> +#include "../virt-dma.h"
>> +#include "dpdmai_cmd.h"
>> +#include "dpdmai.h"
>> +#include "dpaa2-qdma.h"
>> +
>> +static bool smmu_disable = true;
>> +
>> +static struct dpaa2_qdma_chan *to_dpaa2_qdma_chan(struct dma_chan
>> +*chan) {
>> +     return container_of(chan, struct dpaa2_qdma_chan, vchan.chan); }
>> +
>> +static struct dpaa2_qdma_comp *to_fsl_qdma_comp(struct virt_dma_desc
>> +*vd) {
>> +     return container_of(vd, struct dpaa2_qdma_comp, vdesc); }
>> +
>> +static int dpaa2_qdma_alloc_chan_resources(struct dma_chan *chan) {
>> +     struct dpaa2_qdma_chan *dpaa2_chan =
>to_dpaa2_qdma_chan(chan);
>> +     struct dpaa2_qdma_engine *dpaa2_qdma = dpaa2_chan->qdma;
>> +     struct device *dev = &dpaa2_qdma->priv->dpdmai_dev->dev;
>> +
>> +     dpaa2_chan->fd_pool = dma_pool_create("fd_pool", dev,
>> +                                           FD_POOL_SIZE, 32,
>0);
>> +     if (!dpaa2_chan->fd_pool)
>> +             return -ENOMEM;
>> +
>> +     return dpaa2_qdma->desc_allocated++; }
>> +
>> +static void dpaa2_qdma_free_chan_resources(struct dma_chan *chan) {
>> +     struct dpaa2_qdma_chan *dpaa2_chan =
>to_dpaa2_qdma_chan(chan);
>> +     struct dpaa2_qdma_engine *dpaa2_qdma = dpaa2_chan->qdma;
>> +     unsigned long flags;
>> +
>> +     LIST_HEAD(head);
>> +
>> +     spin_lock_irqsave(&dpaa2_chan->vchan.lock, flags);
>> +     vchan_get_all_descriptors(&dpaa2_chan->vchan, &head);
>> +     spin_unlock_irqrestore(&dpaa2_chan->vchan.lock, flags);
>> +
>> +     vchan_dma_desc_free_list(&dpaa2_chan->vchan, &head);
>> +
>> +     dpaa2_dpdmai_free_comp(dpaa2_chan,
>&dpaa2_chan->comp_used);
>> +     dpaa2_dpdmai_free_comp(dpaa2_chan, &dpaa2_chan->comp_free);
>> +
>> +     dma_pool_destroy(dpaa2_chan->fd_pool);
>> +     dpaa2_qdma->desc_allocated--;
>> +}
>> +
>> +/*
>> + * Request a command descriptor for enqueue.
>> + */
>> +static struct dpaa2_qdma_comp *
>> +dpaa2_qdma_request_desc(struct dpaa2_qdma_chan *dpaa2_chan) {
>> +     struct dpaa2_qdma_comp *comp_temp = NULL;
>> +     unsigned long flags;
>> +
>> +     spin_lock_irqsave(&dpaa2_chan->queue_lock, flags);
>> +     if (list_empty(&dpaa2_chan->comp_free)) {
>> +             spin_unlock_irqrestore(&dpaa2_chan->queue_lock, flags);
>> +             comp_temp = kzalloc(sizeof(*comp_temp), GFP_KERNEL);
>
>GFP_NOWAIT?
[Peng Ma] Got it.
>
>> +             if (!comp_temp)
>> +                     goto err;
>> +             comp_temp->fd_virt_addr =
>> +                     dma_pool_alloc(dpaa2_chan->fd_pool,
>GFP_NOWAIT,
>> +                                    &comp_temp->fd_bus_addr);
>> +             if (!comp_temp->fd_virt_addr)
>
>err handling seems incorrect, you dont clean up, caller doesnt check return!
>
[Peng Ma] Yes, It's my fault.
>> +                     goto err;
>> +
>> +             comp_temp->fl_virt_addr =
>> +                     (void *)((struct dpaa2_fd *)
>> +                             comp_temp->fd_virt_addr + 1);
>
>casts and pointer math, what could go wrong!! This doesnt smell right!
>
>> +             comp_temp->fl_bus_addr = comp_temp->fd_bus_addr +
>> +                                     sizeof(struct dpaa2_fd);
>
>why not use fl_virt_addr and get the bus_address?
What you mean is I should use virt_to_phys to get the bus_address?
>
>> +             comp_temp->desc_virt_addr =
>> +                     (void *)((struct dpaa2_fl_entry *)
>> +                             comp_temp->fl_virt_addr + 3);
>> +             comp_temp->desc_bus_addr = comp_temp->fl_bus_addr +
>> +                             sizeof(struct dpaa2_fl_entry) * 3;
>
>pointer math in the two calls doesnt match and as I said doesnt look good...
Should I do this as follows:
-               comp_temp->fl_virt_addr =
-                       (void *)((struct dpaa2_fd *)
-                               comp_temp->fd_virt_addr + 1);
-               comp_temp->fl_bus_addr = comp_temp->fd_bus_addr +
-                                       sizeof(struct dpaa2_fd);
-               comp_temp->desc_virt_addr =
-                       (void *)((struct dpaa2_fl_entry *)
-                               comp_temp->fl_virt_addr + 3);
-               comp_temp->desc_bus_addr = comp_temp->fl_bus_addr +
-                               sizeof(struct dpaa2_fl_entry) * 3;
+               comp_temp->fd_virt_addr = (struct dpaa2_fd *)virt_addr_head++;
+               comp_temp->fl_virt_addr = (struct dpaa2_fl_entry *)virt_addr_head;
+               comp_temp->fl_bus_addr = virt_to_phys(comp_temp->fl_virt_addr);
+               virt_addr_head = (struct dpaa2_fl_entry *)virt_addr_head + 3;
+               comp_temp->desc_virt_addr = (struct dpaa2_qdma_sd_d *)virt_addr_head;
+               comp_temp->desc_bus_addr = virt_to_phys(comp_temp->desc_virt_addr);
>
>> +
>> +             comp_temp->qchan = dpaa2_chan;
>> +             return comp_temp;
>> +     }
>> +     comp_temp = list_first_entry(&dpaa2_chan->comp_free,
>> +                                  struct dpaa2_qdma_comp, list);
>> +     list_del(&comp_temp->list);
>> +     spin_unlock_irqrestore(&dpaa2_chan->queue_lock, flags);
>> +
>> +     comp_temp->qchan = dpaa2_chan;
>> +err:
>> +     return comp_temp;
>> +}
>> +
>> +static void
>> +dpaa2_qdma_populate_fd(u32 format, struct dpaa2_qdma_comp
>> +*dpaa2_comp) {
>> +     struct dpaa2_fd *fd;
>> +
>> +     fd = (struct dpaa2_fd *)dpaa2_comp->fd_virt_addr;
>
>whats with the casts! you seem to like them! You are casting away from void!
This will avoid after change fd_virt_addr type.
>
>> +     memset(fd, 0, sizeof(struct dpaa2_fd));
>> +
>> +     /* fd populated */
>> +     dpaa2_fd_set_addr(fd, dpaa2_comp->fl_bus_addr);
>> +     /* Bypass memory translation, Frame list format, short length disable
>*/
>> +     /* we need to disable BMT if fsl-mc use iova addr */
>> +     if (smmu_disable)
>> +             dpaa2_fd_set_bpid(fd, QMAN_FD_BMT_ENABLE);
>> +     dpaa2_fd_set_format(fd, QMAN_FD_FMT_ENABLE |
>> + QMAN_FD_SL_DISABLE);
>> +
>> +     dpaa2_fd_set_frc(fd, format | QDMA_SER_CTX); }
>> +
>> +/* first frame list for descriptor buffer */ static void
>> +dpaa2_qdma_populate_first_framel(struct dpaa2_fl_entry *f_list,
>> +                              struct dpaa2_qdma_comp
>*dpaa2_comp,
>> +                              bool wrt_changed) {
>> +     struct dpaa2_qdma_sd_d *sdd;
>> +
>> +     sdd = (struct dpaa2_qdma_sd_d *)dpaa2_comp->desc_virt_addr;
>
>again
Same to before.
>
>> +     memset(sdd, 0, 2 * (sizeof(*sdd)));
>> +
>> +     /* source descriptor CMD */
>> +     sdd->cmd = cpu_to_le32(QDMA_SD_CMD_RDTTYPE_COHERENT);
>> +     sdd++;
>> +
>> +     /* dest descriptor CMD */
>> +     if (wrt_changed)
>> +             sdd->cmd =
>cpu_to_le32(LX2160_QDMA_DD_CMD_WRTTYPE_COHERENT);
>> +     else
>> +             sdd->cmd =
>cpu_to_le32(QDMA_DD_CMD_WRTTYPE_COHERENT);
>> +
>> +     memset(f_list, 0, sizeof(struct dpaa2_fl_entry));
>> +
>> +     /* first frame list to source descriptor */
>> +     dpaa2_fl_set_addr(f_list, dpaa2_comp->desc_bus_addr);
>> +     dpaa2_fl_set_len(f_list, 0x20);
>> +     dpaa2_fl_set_format(f_list, QDMA_FL_FMT_SBF |
>QDMA_FL_SL_LONG);
>> +
>> +     /* bypass memory translation */
>> +     if (smmu_disable)
>> +             f_list->bpid = cpu_to_le16(QDMA_FL_BMT_ENABLE); }
>> +
>> +/* source and destination frame list */ static void
>> +dpaa2_qdma_populate_frames(struct dpaa2_fl_entry *f_list,
>> +                        dma_addr_t dst, dma_addr_t src,
>> +                        size_t len, uint8_t fmt) {
>> +     /* source frame list to source buffer */
>> +     memset(f_list, 0, sizeof(struct dpaa2_fl_entry));
>> +
>> +     dpaa2_fl_set_addr(f_list, src);
>> +     dpaa2_fl_set_len(f_list, len);
>> +
>> +     /* single buffer frame or scatter gather frame */
>> +     dpaa2_fl_set_format(f_list, (fmt | QDMA_FL_SL_LONG));
>> +
>> +     /* bypass memory translation */
>> +     if (smmu_disable)
>> +             f_list->bpid = cpu_to_le16(QDMA_FL_BMT_ENABLE);
>> +
>> +     f_list++;
>> +
>> +     /* destination frame list to destination buffer */
>> +     memset(f_list, 0, sizeof(struct dpaa2_fl_entry));
>> +
>> +     dpaa2_fl_set_addr(f_list, dst);
>> +     dpaa2_fl_set_len(f_list, len);
>> +     dpaa2_fl_set_format(f_list, (fmt | QDMA_FL_SL_LONG));
>> +     /* single buffer frame or scatter gather frame */
>> +     dpaa2_fl_set_final(f_list, QDMA_FL_F);
>> +     /* bypass memory translation */
>> +     if (smmu_disable)
>> +             f_list->bpid = cpu_to_le16(QDMA_FL_BMT_ENABLE); }
>> +
>> +static struct dma_async_tx_descriptor *dpaa2_qdma_prep_memcpy(struct
>> +dma_chan *chan, dma_addr_t dst,
>> +                     dma_addr_t src, size_t len, ulong flags) {
>> +     struct dpaa2_qdma_chan *dpaa2_chan =
>to_dpaa2_qdma_chan(chan);
>> +     struct dpaa2_qdma_engine *dpaa2_qdma;
>> +     struct dpaa2_qdma_comp *dpaa2_comp;
>> +     struct dpaa2_fl_entry *f_list;
>> +     bool wrt_changed;
>> +     u32 format;
>> +
>> +     dpaa2_qdma = dpaa2_chan->qdma;
>> +     dpaa2_comp = dpaa2_qdma_request_desc(dpaa2_chan);
>> +     wrt_changed = (bool)dpaa2_qdma->qdma_wrtype_fixup;
>> +
>> +#ifdef LONG_FORMAT
>
> compile flag and define, so else part is dead code??
Ok, I will add it to Kconfig.
>
>> +     format = QDMA_FD_LONG_FORMAT;
>> +#else
>> +     format = QDMA_FD_SHORT_FORMAT;
>> +#endif
>> +     /* populate Frame descriptor */
>> +     dpaa2_qdma_populate_fd(format, dpaa2_comp);
>> +
>> +     f_list = (struct dpaa2_fl_entry *)dpaa2_comp->fl_virt_addr;
>> +
>> +#ifdef LONG_FORMAT
>> +     /* first frame list for descriptor buffer (logn format) */
>> +     dpaa2_qdma_populate_first_framel(f_list, dpaa2_comp,
>> +wrt_changed);
>> +
>> +     f_list++;
>> +#endif
>> +
>> +     dpaa2_qdma_populate_frames(f_list, dst, src, len,
>> + QDMA_FL_FMT_SBF);
>> +
>> +     return vchan_tx_prep(&dpaa2_chan->vchan, &dpaa2_comp->vdesc,
>> +flags); }
>> +
>> +static enum
>> +dma_status dpaa2_qdma_tx_status(struct dma_chan *chan,
>> +                             dma_cookie_t cookie,
>> +                             struct dma_tx_state *txstate) {
>> +     return dma_cookie_status(chan, cookie, txstate); }
>> +
>> +static void dpaa2_qdma_issue_pending(struct dma_chan *chan) {
>> +     struct dpaa2_qdma_chan *dpaa2_chan =
>to_dpaa2_qdma_chan(chan);
>> +     struct dpaa2_qdma_engine *dpaa2_qdma = dpaa2_chan->qdma;
>> +     struct dpaa2_qdma_priv *priv = dpaa2_qdma->priv;
>> +     struct dpaa2_qdma_comp *dpaa2_comp;
>> +     struct virt_dma_desc *vdesc;
>> +     struct dpaa2_fd *fd;
>> +     unsigned long flags;
>> +     int err;
>> +
>> +     spin_lock_irqsave(&dpaa2_chan->queue_lock, flags);
>> +     spin_lock(&dpaa2_chan->vchan.lock);
>> +     if (vchan_issue_pending(&dpaa2_chan->vchan)) {
>> +             vdesc = vchan_next_desc(&dpaa2_chan->vchan);
>> +             if (!vdesc)
>> +                     goto err_enqueue;
>> +             dpaa2_comp = to_fsl_qdma_comp(vdesc);
>> +
>> +             fd = (struct dpaa2_fd *)dpaa2_comp->fd_virt_addr;
>> +
>> +             list_del(&vdesc->node);
>> +             list_add_tail(&dpaa2_comp->list,
>> + &dpaa2_chan->comp_used);
>
>what does this list do?
>
It is will used in interrupt to deal dma jobs.
>> +
>> +             /* TOBO: priority hard-coded to zero */
>
>You mean TODO?
Yes.
>
>> +             err = dpaa2_io_service_enqueue_fq(NULL,
>> +                             priv->tx_queue_attr[0].fqid, fd);
>> +             if (err) {
>> +                     list_del(&dpaa2_comp->list);
>> +                     list_add_tail(&dpaa2_comp->list,
>> +                                   &dpaa2_chan->comp_free);
>> +             }
>> +     }
>> +err_enqueue:
>> +     spin_unlock(&dpaa2_chan->vchan.lock);
>> +     spin_unlock_irqrestore(&dpaa2_chan->queue_lock, flags); }
>> +
>> +static int __cold dpaa2_qdma_setup(struct fsl_mc_device *ls_dev) {
>> +     struct dpaa2_qdma_priv_per_prio *ppriv;
>> +     struct device *dev = &ls_dev->dev;
>> +     struct dpaa2_qdma_priv *priv;
>> +     u8 prio_def = DPDMAI_PRIO_NUM;
>> +     int err;
>> +     int i;
>> +
>> +     priv = dev_get_drvdata(dev);
>> +
>> +     priv->dev = dev;
>> +     priv->dpqdma_id = ls_dev->obj_desc.id;
>> +
>> +     /*Get the handle for the DPDMAI this interface is associate with
>> + */
>
>Please run checkpatch, it should have told you that you need space after
>comment marker /* foo...
>
Ok, I will check it with --strict.
>> +     err = dpdmai_open(priv->mc_io, 0, priv->dpqdma_id,
>&ls_dev->mc_handle);
>> +     if (err) {
>> +             dev_err(dev, "dpdmai_open() failed\n");
>> +             return err;
>> +     }
>> +     dev_info(dev, "Opened dpdmai object successfully\n");
>> +
>> +     err = dpdmai_get_attributes(priv->mc_io, 0, ls_dev->mc_handle,
>> +                                 &priv->dpdmai_attr);
>> +     if (err) {
>> +             dev_err(dev, "dpdmai_get_attributes() failed\n");
>> +             return err;
>
>so you dont close what you opened in dpdmai_open() Please give a serious
>thought and testing to this driver
OK, got it.
>
>> +     }
>> +
>> +     if (priv->dpdmai_attr.version.major > DPDMAI_VER_MAJOR) {
>> +             dev_err(dev, "DPDMAI major version mismatch\n"
>> +                          "Found %u.%u, supported version
>is %u.%u\n",
>> +                             priv->dpdmai_attr.version.major,
>> +                             priv->dpdmai_attr.version.minor,
>> +                             DPDMAI_VER_MAJOR,
>DPDMAI_VER_MINOR);
>> +     }
>> +
>> +     if (priv->dpdmai_attr.version.minor > DPDMAI_VER_MINOR) {
>> +             dev_err(dev, "DPDMAI minor version mismatch\n"
>> +                          "Found %u.%u, supported version
>is %u.%u\n",
>> +                             priv->dpdmai_attr.version.major,
>> +                             priv->dpdmai_attr.version.minor,
>> +                             DPDMAI_VER_MAJOR,
>DPDMAI_VER_MINOR);
>
>what is the implication of these error, why not bail out on these?
There should be return.
>
>> +     }
>> +
>> +     priv->num_pairs = min(priv->dpdmai_attr.num_of_priorities,
>prio_def);
>> +     ppriv = kcalloc(priv->num_pairs, sizeof(*ppriv), GFP_KERNEL);
>
>what is the context of the fn, sleepy, atomic?
This function will be called on qdma probe,Here is not a critical area,
What's the problem about to use GFP_KERNEL, please let me know.
>
>> +     if (!ppriv) {
>> +             dev_err(dev, "kzalloc for ppriv failed\n");
>
>this need not be logged, core will do so
OK.
>
>> +             return -1;
>
>really -1??
I will update.
>
>I think this driver needs more work, please fix these issues in the comments
>above and also see in rest of the code
OK, I will check all of those patch about these issues in rest of the code. Thanks.
>
Best Regards,
Peng
>--
>~Vinod