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Date: Thu, 28 Feb 2019 15:51:12 +0000
From: Liming Sun <lsun@...lanox.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
CC: David Woods <dwoods@...lanox.com>,
Andy Shevchenko <andy@...radead.org>,
Darren Hart <dvhart@...radead.org>,
Vadim Pasternak <vadimp@...lanox.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Platform Driver <platform-driver-x86@...r.kernel.org>
Subject: RE: [PATCH v9] platform/mellanox: Add TmFifo driver for Mellanox
BlueField Soc
Thanks Andy for the comments. Please see the responses below.
I'll also post the v10 patch after this email.
Regards,
Liming
> -----Original Message-----
> From: Andy Shevchenko <andy.shevchenko@...il.com>
> Sent: Wednesday, February 13, 2019 1:11 PM
> To: Liming Sun <lsun@...lanox.com>
> Cc: David Woods <dwoods@...lanox.com>; Andy Shevchenko <andy@...radead.org>; Darren Hart <dvhart@...radead.org>; Vadim
> Pasternak <vadimp@...lanox.com>; Linux Kernel Mailing List <linux-kernel@...r.kernel.org>; Platform Driver <platform-driver-
> x86@...r.kernel.org>
> Subject: Re: [PATCH v9] platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc
>
> On Wed, Feb 13, 2019 at 3:27 PM Liming Sun <lsun@...lanox.com> wrote:
> >
> > This commit adds the TmFifo platform driver for Mellanox BlueField
> > Soc. TmFifo is a shared FIFO which enables external host machine
> > to exchange data with the SoC via USB or PCIe. The driver is based
> > on virtio framework and has console and network access enabled.
>
> Thanks for an update, my comments below.
>
> Again, to Mellanox: guys, please, establish internal mailing list for
> review and don't come with such quality of code.
Yes, the patch went through internal review. I updated the
Reviewed-by section of the commit message.
>
> Next time I would like to see Reviewed-by from Mellanox people I know,
> like Vadim or Leon.
>
> > +config MLXBF_TMFIFO
> > + tristate "Mellanox BlueField SoC TmFifo platform driver"
>
> > + depends on ARM64 && ACPI && VIRTIO_CONSOLE && VIRTIO_NET
>
> Split this to three logical parts.
Updated in v10.
>
> > + help
> > + Say y here to enable TmFifo support. The TmFifo driver provides
> > + platform driver support for the TmFifo which supports console
> > + and networking based on the virtio framework.
>
> > obj-$(CONFIG_MLXREG_HOTPLUG) += mlxreg-hotplug.o
> > obj-$(CONFIG_MLXREG_IO) += mlxreg-io.o
> > +obj-$(CONFIG_MLXBF_TMFIFO) += mlxbf-tmfifo.o
>
> I would suggest to keep it sorted.
Updated in v10.
>
> > +#define MLXBF_TMFIFO_TX_DATA 0x0
>
> I suggest to use same fixed format for offsets.
> Here, for example, 0x00 would be better.
>
> > +#define MLXBF_TMFIFO_TX_STS__COUNT_RMASK 0x1ff
> > +#define MLXBF_TMFIFO_TX_STS__COUNT_MASK 0x1ff
>
> #include <linux/bits.h>
> ...
> GENMASK()
Updated in v10.
>
> > +#define MLXBF_TMFIFO_TX_CTL__LWM_RMASK 0xff
> > +#define MLXBF_TMFIFO_TX_CTL__LWM_MASK 0xff
>
> > +#define MLXBF_TMFIFO_TX_CTL__HWM_RMASK 0xff
> > +#define MLXBF_TMFIFO_TX_CTL__HWM_MASK 0xff00
>
> > +#define MLXBF_TMFIFO_TX_CTL__MAX_ENTRIES_RMASK 0x1ff
> > +#define MLXBF_TMFIFO_TX_CTL__MAX_ENTRIES_MASK 0x1ff00000000ULL
>
> GENMASK() / GENMASK_ULL()
Updated in v10.
>
> > +#define MLXBF_TMFIFO_RX_STS__COUNT_RMASK 0x1ff
> > +#define MLXBF_TMFIFO_RX_STS__COUNT_MASK 0x1ff
>
> GENMASK()
Updated in v10.
>
> > +#define MLXBF_TMFIFO_RX_CTL__LWM_RMASK 0xff
> > +#define MLXBF_TMFIFO_RX_CTL__LWM_MASK 0xff
>
> > +#define MLXBF_TMFIFO_RX_CTL__HWM_RMASK 0xff
> > +#define MLXBF_TMFIFO_RX_CTL__HWM_MASK 0xff00
>
> > +#define MLXBF_TMFIFO_RX_CTL__MAX_ENTRIES_RMASK 0x1ff
> > +#define MLXBF_TMFIFO_RX_CTL__MAX_ENTRIES_MASK 0x1ff00000000ULL
>
> Ditto.
Updated in v10.
>
> > +#include <linux/acpi.h>
> > +#include <linux/byteorder/generic.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/cache.h>
> > +#include <linux/device.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/efi.h>
> > +#include <linux/io.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/kernel.h>
> > +#include <linux/math64.h>
> > +#include <linux/module.h>
> > +#include <linux/moduleparam.h>
> > +#include <linux/mutex.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/resource.h>
> > +#include <linux/slab.h>
> > +#include <linux/types.h>
> > +#include <linux/version.h>
> > +#include <linux/virtio.h>
> > +#include <linux/virtio_config.h>
> > +#include <linux/virtio_console.h>
> > +#include <linux/virtio_ids.h>
> > +#include <linux/virtio_net.h>
> > +#include <linux/virtio_ring.h>
>
> Do you need all of them?
Cleaned up quite a few and updated in v10.
>
> > +#define MLXBF_TMFIFO_VRING_SIZE 1024
>
> SZ_1K ?
Updated in v10.
>
> > +/* Console Tx buffer size. */
> > +#define MLXBF_TMFIFO_CONS_TX_BUF_SIZE (32 * 1024)
>
> SZ_32K ?
Updated in v10.
>
> > +/* House-keeping timer interval. */
> > +static int mlxbf_tmfifo_timer_interval = HZ / 10;
>
> > +/* Global lock. */
>
> Noise. Either explain what it protects, or remove.
Removed in v10.
>
> > +static DEFINE_MUTEX(mlxbf_tmfifo_lock);
>
> > +/* Struct declaration. */
>
> Noise.
Removed in v10.
>
> > +/* Structure to maintain the ring state. */
> > +struct mlxbf_tmfifo_vring {
> > + void *va; /* virtual address */
> > + dma_addr_t dma; /* dma address */
> > + struct virtqueue *vq; /* virtqueue pointer */
> > + struct vring_desc *desc; /* current desc */
> > + struct vring_desc *desc_head; /* current desc head */
> > + int cur_len; /* processed len in current desc */
> > + int rem_len; /* remaining length to be processed */
> > + int size; /* vring size */
> > + int align; /* vring alignment */
> > + int id; /* vring id */
> > + int vdev_id; /* TMFIFO_VDEV_xxx */
> > + u32 pkt_len; /* packet total length */
> > + u16 next_avail; /* next avail desc id */
> > + struct mlxbf_tmfifo *fifo; /* pointer back to the tmfifo */
> > +};
>
> Perhaps kernel-doc?
Updated in v10.
>
> > +/* Interrupt types. */
> > +enum {
> > + MLXBF_TM_RX_LWM_IRQ, /* Rx low water mark irq */
> > + MLXBF_TM_RX_HWM_IRQ, /* Rx high water mark irq */
> > + MLXBF_TM_TX_LWM_IRQ, /* Tx low water mark irq */
> > + MLXBF_TM_TX_HWM_IRQ, /* Tx high water mark irq */
> > + MLXBF_TM_IRQ_CNT
>
> CNT...
>
> > +};
> > +
> > +/* Ring types (Rx & Tx). */
> > +enum {
> > + MLXBF_TMFIFO_VRING_RX, /* Rx ring */
> > + MLXBF_TMFIFO_VRING_TX, /* Tx ring */
> > + MLXBF_TMFIFO_VRING_NUM
>
> ...NUM
>
> Perhaps one style for max numbers?
Updated in v10.
>
> > +};
>
> > +
> > +/* Structure for the virtual device. */
> > +struct mlxbf_tmfifo_vdev {
> > + struct virtio_device vdev; /* virtual device */
> > + u8 status;
> > + u64 features;
> > + union { /* virtio config space */
> > + struct virtio_console_config cons;
> > + struct virtio_net_config net;
> > + } config;
>
> Describe, which field allows to distinguish what type of the data is in a union.
Added comments in v10.
>
> > + struct mlxbf_tmfifo_vring vrings[MLXBF_TMFIFO_VRING_NUM];
> > + u8 *tx_buf; /* tx buffer */
> > + u32 tx_head; /* tx buffer head */
> > + u32 tx_tail; /* tx buffer tail */
> > +};
>
> kernel-doc?
Updated in v10
>
> > +/* Structure of the interrupt information. */
> > +struct mlxbf_tmfifo_irq_info {
> > + struct mlxbf_tmfifo *fifo; /* tmfifo structure */
> > + int irq; /* interrupt number */
> > + int index; /* array index */
> > +};
>
> Ditto.
Updated in v10
>
> > +
> > +/* Structure of the TmFifo information. */
> > +struct mlxbf_tmfifo {
> > + struct mlxbf_tmfifo_vdev *vdev[MLXBF_TMFIFO_VDEV_MAX]; /* devices */
> > + struct platform_device *pdev; /* platform device */
> > + struct mutex lock; /* fifo lock */
> > + void __iomem *rx_base; /* mapped register base */
> > + void __iomem *tx_base; /* mapped register base */
> > + int tx_fifo_size; /* number of entries of the Tx FIFO */
> > + int rx_fifo_size; /* number of entries of the Rx FIFO */
> > + unsigned long pend_events; /* pending bits for deferred process */
> > + struct mlxbf_tmfifo_irq_info irq_info[MLXBF_TM_IRQ_CNT]; /* irq info */
> > + struct work_struct work; /* work struct for deferred process */
> > + struct timer_list timer; /* keepalive timer */
> > + struct mlxbf_tmfifo_vring *vring[2]; /* current Tx/Rx ring */
> > + bool is_ready; /* ready flag */
> > + spinlock_t spin_lock; /* spin lock */
> > +};
>
> Ditto.
Updated in v10
>
> > +/* Use a union struction for 64-bit little/big endian. */
>
> What does this mean?
Updated in v10 with the following comments to explain it.
/*
* It's expected to send 64-bit little-endian value (__le64) into the TmFifo.
* readq() and writeq() expect u64 instead. A union structure is used here
* to workaround the explicit casting usage like writeq(*(u64 *)&data_le).
*/
>
> > +union mlxbf_tmfifo_data_64bit {
> > + u64 data;
> > + __le64 data_le;
> > +};
> > +
> > +/* Message header used to demux data in the TmFifo. */
> > +union mlxbf_tmfifo_msg_hdr {
> > + struct {
> > + u8 type; /* message type */
> > + __be16 len; /* payload length */
> > + u8 unused[5]; /* reserved, set to 0 */
> > + } __packed;
>
> It's already packed. No?
It's not packed by default due to the 16-bit len. We need the '__packed'
to make sure the size of the structure is 8 bytes.
>
> > + union mlxbf_tmfifo_data_64bit u; /* 64-bit data */
> > +};
>
> > +/* MTU setting of the virtio-net interface. */
> > +#define MLXBF_TMFIFO_NET_MTU 1500
>
> Don't we have this globally defined?
Updated in v10
>
> > +/* Supported virtio-net features. */
> > +#define MLXBF_TMFIFO_NET_FEATURES ((1UL << VIRTIO_NET_F_MTU) | \
> > + (1UL << VIRTIO_NET_F_STATUS) | \
> > + (1UL << VIRTIO_NET_F_MAC))
>
> BIT_UL() ?
Updated in v10
>
> > +/* Function declarations. */
>
> Noise.
Removed in v10
>
> > +static int mlxbf_tmfifo_remove(struct platform_device *pdev);
>
> Why do you need forward declaration for this?
Removed in v10
>
> > +/* Return the consumed Tx buffer space. */
> > +static int mlxbf_tmfifo_vdev_tx_buf_len(struct mlxbf_tmfifo_vdev *vdev)
> > +{
> > + return ((vdev->tx_tail >= vdev->tx_head) ?
> > + (vdev->tx_tail - vdev->tx_head) :
> > + (MLXBF_TMFIFO_CONS_TX_BUF_SIZE - vdev->tx_head +
> > + vdev->tx_tail));
>
> Split this for better reading.
Updated in v10
>
> > +}
> > +
> > +/* Return the available Tx buffer space. */
> > +static int mlxbf_tmfifo_vdev_tx_buf_avail(struct mlxbf_tmfifo_vdev *vdev)
> > +{
> > + return (MLXBF_TMFIFO_CONS_TX_BUF_RSV_SIZE -
> > + mlxbf_tmfifo_vdev_tx_buf_len(vdev));
>
> Redundant parens.
> Moreover, you might consider temporary variable for better reading.
Updated in v10
>
> > +}
> > +
> > +/* Update Rx/Tx buffer index pointer. */
> > +static void mlxbf_tmfifo_vdev_tx_buf_index_inc(u32 *index, u32 len)
> > +{
> > + *index += len;
> > + if (*index >= MLXBF_TMFIFO_CONS_TX_BUF_SIZE)
> > + *index -= MLXBF_TMFIFO_CONS_TX_BUF_SIZE;
> > +}
> > +
> > +/* Allocate vrings for the fifo. */
> > +static int mlxbf_tmfifo_alloc_vrings(struct mlxbf_tmfifo *fifo,
> > + struct mlxbf_tmfifo_vdev *tm_vdev,
> > + int vdev_id)
> > +{
> > + struct mlxbf_tmfifo_vring *vring;
> > + dma_addr_t dma;
> > + int i, size;
> > + void *va;
> > +
> > + for (i = 0; i < ARRAY_SIZE(tm_vdev->vrings); i++) {
> > + vring = &tm_vdev->vrings[i];
> > + vring->fifo = fifo;
> > + vring->size = MLXBF_TMFIFO_VRING_SIZE;
> > + vring->align = SMP_CACHE_BYTES;
> > + vring->id = i;
> > + vring->vdev_id = vdev_id;
> > +
>
> > + size = PAGE_ALIGN(vring_size(vring->size, vring->align));
>
> Why do you need this?
> dma_alloc_coherent() allocates memory on page granularity anyway.
Updated in v10
>
> > + va = dma_alloc_coherent(tm_vdev->vdev.dev.parent, size, &dma,
> > + GFP_KERNEL);
> > + if (!va) {
>
> > + dev_err(tm_vdev->vdev.dev.parent,
>
> Would be much easy if you have temporary variable for this device.
Updated in v10
>
> > + "dma_alloc_coherent failed\n");
> > + return -ENOMEM;
> > + }
> > +
> > + vring->va = va;
> > + vring->dma = dma;
> > + }
> > +
> > + return 0;
> > +}
>
> > +/* Interrupt handler. */
> > +static irqreturn_t mlxbf_tmfifo_irq_handler(int irq, void *arg)
> > +{
> > + struct mlxbf_tmfifo_irq_info *irq_info;
> > +
> > + irq_info = (struct mlxbf_tmfifo_irq_info *)arg;
>
> Useless casting.
> Assignment can be done in definition block.
Updated in v10
>
> > + if (irq_info->index < MLXBF_TM_IRQ_CNT &&
> > + !test_and_set_bit(irq_info->index, &irq_info->fifo->pend_events))
> > + schedule_work(&irq_info->fifo->work);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +/* Get the next packet descriptor from the vring. */
> > +static struct vring_desc *mlxbf_tmfifo_get_next_desc(struct virtqueue *vq)
> > +{
> > + struct mlxbf_tmfifo_vring *vring;
> > + unsigned int idx, head;
> > + struct vring *vr;
> > +
> > + vr = (struct vring *)virtqueue_get_vring(vq);
>
> Return type is different? Is it safe to cast? Why?
It's 'const' casting. Fixed in v10 to use 'const struct vring *vr' instead.
>
> > + if (!vr)
> > + return NULL;
>
> + blank line
Updated in v10
>
> > + vring = (struct mlxbf_tmfifo_vring *)vq->priv;
>
> Do you need explicit casting?
Updated in v10
>
> > + if (vring->next_avail == virtio16_to_cpu(vq->vdev, vr->avail->idx))
> > + return NULL;
>
> +blank line
Updated in v10
>
> > + idx = vring->next_avail % vr->num;
> > + head = virtio16_to_cpu(vq->vdev, vr->avail->ring[idx]);
> > + if (WARN_ON(head >= vr->num))
> > + return NULL;
> > + vring->next_avail++;
> > +
> > + return &vr->desc[head];
> > +}
> > +
> > +/* Release virtio descriptor. */
> > +static void mlxbf_tmfifo_release_desc(struct virtio_device *vdev,
> > + struct vring *vr, struct vring_desc *desc,
> > + u32 len)
> > +{
> > + u16 idx, vr_idx;
> > +
> > + vr_idx = virtio16_to_cpu(vdev, vr->used->idx);
> > + idx = vr_idx % vr->num;
> > + vr->used->ring[idx].id = cpu_to_virtio32(vdev, desc - vr->desc);
> > + vr->used->ring[idx].len = cpu_to_virtio32(vdev, len);
> > +
> > + /* Virtio could poll and check the 'idx' to decide
> > + * whether the desc is done or not. Add a memory
> > + * barrier here to make sure the update above completes
> > + * before updating the idx.
> > + */
>
> Multi-line comment style is broken.
Updated in v10
>
> > + mb();
> > + vr->used->idx = cpu_to_virtio16(vdev, vr_idx + 1);
> > +}
>
> > +/* House-keeping timer. */
> > +static void mlxbf_tmfifo_timer(struct timer_list *arg)
> > +{
> > + struct mlxbf_tmfifo *fifo;
>
> > + fifo = container_of(arg, struct mlxbf_tmfifo, timer);
>
> Can't be done in the definition block?
Updated in v10
>
> > + /*
> > + * Wake up the work handler to poll the Rx FIFO in case interrupt
> > + * missing or any leftover bytes stuck in the FIFO.
> > + */
> > + test_and_set_bit(MLXBF_TM_RX_HWM_IRQ, &fifo->pend_events);
>
> How do you utilize test results?
Fixed in v10
>
> > +
> > + /*
> > + * Wake up Tx handler in case virtio has queued too many packets
> > + * and are waiting for buffer return.
> > + */
> > + test_and_set_bit(MLXBF_TM_TX_LWM_IRQ, &fifo->pend_events);
>
> Ditto.
Fixed in v10
>
> > +
> > + schedule_work(&fifo->work);
> > +
> > + mod_timer(&fifo->timer, jiffies + mlxbf_tmfifo_timer_interval);
> > +}
>
> > + /* Adjust the size to available space. */
> > + if (size + sizeof(hdr) > avail * sizeof(u64))
> > + size = avail * sizeof(u64) - sizeof(hdr);
>
> Can avail be 0?
It won't be 0. There is a check at the beginning of this function.
The function will return is avail is too small.
>
> > + /* Write header. */
> > + hdr.u.data = 0;
> > + hdr.type = VIRTIO_ID_CONSOLE;
> > + hdr.len = htons(size);
> > + hdr.u.data_le = cpu_to_le64(hdr.u.data);
>
> > + writeq(hdr.u.data, fifo->tx_base + MLXBF_TMFIFO_TX_DATA);
>
> So, this one is not protected anyhow? Potential race condition?
The spin-lock is to protect reference to the ‘tx_buf’, not the read/write of the fifo.
The fifo read/write is protected by mutex. Added a comment in v10 to avoid such
confusion.
>
> > +
> > + spin_lock_irqsave(&fifo->spin_lock, flags);
> > +
> > + while (size > 0) {
> > + addr = cons->tx_buf + cons->tx_head;
> > +
> > + if (cons->tx_head + sizeof(u64) <=
> > + MLXBF_TMFIFO_CONS_TX_BUF_SIZE) {
> > + memcpy(&data, addr, sizeof(u64));
> > + } else {
> > + partial = MLXBF_TMFIFO_CONS_TX_BUF_SIZE - cons->tx_head;
> > + memcpy(&data, addr, partial);
> > + memcpy((u8 *)&data + partial, cons->tx_buf,
> > + sizeof(u64) - partial);
> > + }
> > + writeq(data, fifo->tx_base + MLXBF_TMFIFO_TX_DATA);
> > +
> > + if (size >= sizeof(u64)) {
> > + mlxbf_tmfifo_vdev_tx_buf_index_inc(&cons->tx_head,
> > + sizeof(u64));
> > + size -= sizeof(u64);
> > + } else {
> > + mlxbf_tmfifo_vdev_tx_buf_index_inc(&cons->tx_head,
> > + size);
> > + size = 0;
> > + }
> > + }
> > +
> > + spin_unlock_irqrestore(&fifo->spin_lock, flags);
> > +}
>
> > + /* Rx/Tx one word (8 bytes) if not done. */
> > + if (vring->cur_len != len)
> > + mlxbf_tmfifo_rxtx_word(fifo, vdev, vring, desc, is_rx, avail,
> > + len);
>
> In such case better to keep it in one line.
Updated in v10
>
> > +/* Get the array of feature bits for this device. */
> > +static u64 mlxbf_tmfifo_virtio_get_features(struct virtio_device *vdev)
> > +{
> > + struct mlxbf_tmfifo_vdev *tm_vdev;
> > +
> > + tm_vdev = container_of(vdev, struct mlxbf_tmfifo_vdev, vdev);
> > + return tm_vdev->features;
> > +}
> > +
> > +/* Confirm device features to use. */
> > +static int mlxbf_tmfifo_virtio_finalize_features(struct virtio_device *vdev)
> > +{
> > + struct mlxbf_tmfifo_vdev *tm_vdev;
> > +
>
> > + tm_vdev = container_of(vdev, struct mlxbf_tmfifo_vdev, vdev);
>
> This is candidate to be a macro
>
> #define mlxbt_vdev_to_tmfifo(...) ...
Updated in v10
>
> > + tm_vdev->features = vdev->features;
> > +
> > + return 0;
> > +}
>
> > +/* Create vdev type in a tmfifo. */
> > +static int mlxbf_tmfifo_create_vdev(struct device *dev,
> > + struct mlxbf_tmfifo *fifo,
> > + int vdev_id, u64 features,
> > + void *config, u32 size)
> > +{
> > + struct mlxbf_tmfifo_vdev *tm_vdev;
> > + int ret = 0;
> > +
> > + mutex_lock(&fifo->lock);
> > +
> > + tm_vdev = fifo->vdev[vdev_id];
> > + if (tm_vdev) {
> > + dev_err(dev, "vdev %d already exists\n", vdev_id);
> > + ret = -EEXIST;
> > + goto fail;
> > + }
> > +
> > + tm_vdev = devm_kzalloc(dev, sizeof(*tm_vdev), GFP_KERNEL);
> > + if (!tm_vdev) {
> > + ret = -ENOMEM;
> > + goto fail;
> > + }
> > +
> > + tm_vdev->vdev.id.device = vdev_id;
> > + tm_vdev->vdev.config = &mlxbf_tmfifo_virtio_config_ops;
> > + tm_vdev->vdev.dev.parent = &fifo->pdev->dev;
> > + tm_vdev->features = features;
> > + if (config)
> > + memcpy(&tm_vdev->config, config, size);
> > + if (mlxbf_tmfifo_alloc_vrings(fifo, tm_vdev, vdev_id)) {
> > + dev_err(dev, "unable to allocate vring\n");
> > + ret = -ENOMEM;
> > + goto fail;
> > + }
> > + if (vdev_id == VIRTIO_ID_CONSOLE)
>
> > + tm_vdev->tx_buf = devm_kmalloc(dev,
> > + MLXBF_TMFIFO_CONS_TX_BUF_SIZE,
> > + GFP_KERNEL);
>
> Are you sure devm_ suits here?
I think it's ok. The tx_buf is normal memory for output buffer.
It's running on SoC and the TmFifo is always there. So it's
allocated at init and supposed to be released on module remove.
>
> > + fifo->vdev[vdev_id] = tm_vdev;
> > +
> > + /* Register the virtio device. */
> > + ret = register_virtio_device(&tm_vdev->vdev);
> > + if (ret) {
> > + dev_err(&fifo->pdev->dev, "register_virtio_device failed\n");
> > + goto register_fail;
> > + }
> > +
> > + mutex_unlock(&fifo->lock);
> > + return 0;
> > +
> > +register_fail:
> > + mlxbf_tmfifo_free_vrings(fifo, vdev_id);
> > + fifo->vdev[vdev_id] = NULL;
> > +fail:
> > + mutex_unlock(&fifo->lock);
> > + return ret;
> > +}
>
> > +/* Read the configured network MAC address from efi variable. */
> > +static void mlxbf_tmfifo_get_cfg_mac(u8 *mac)
> > +{
> > + efi_guid_t guid = EFI_GLOBAL_VARIABLE_GUID;
> > + efi_status_t status;
> > + unsigned long size;
> > + u8 buf[6];
> > +
> > + size = sizeof(buf);
> > + status = efi.get_variable(mlxbf_tmfifo_efi_name, &guid, NULL, &size,
> > + buf);
> > + if (status == EFI_SUCCESS && size == sizeof(buf))
> > + memcpy(mac, buf, sizeof(buf));
> > +}
>
> Shouldn't be rather helper in EFI lib in kernel?
It's a little strange that there seems no such existing lib function. I searched
a little bit in kernel tree like below, they seem using the efi.get_variable()
approach.
arch/x86/kernel/ima_arch.c
drivers/scsi/isci/probe_roms.c
security/integrity/platform_certs/load_uefi.c
>
> > +/* Probe the TMFIFO. */
> > +static int mlxbf_tmfifo_probe(struct platform_device *pdev)
> > +{
> > + struct virtio_net_config net_config;
> > + struct resource *rx_res, *tx_res;
> > + struct mlxbf_tmfifo *fifo;
> > + int i, ret;
> > +
> > + /* Get the resource of the Rx FIFO. */
> > + rx_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + if (!rx_res)
> > + return -ENODEV;
> > +
> > + /* Get the resource of the Tx FIFO. */
> > + tx_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> > + if (!tx_res)
> > + return -ENODEV;
> > +
> > + if (!devm_request_mem_region(&pdev->dev, rx_res->start,
> > + resource_size(rx_res), "bf-tmfifo"))
> > + return -EBUSY;
> > +
> > + if (!devm_request_mem_region(&pdev->dev, tx_res->start,
> > + resource_size(tx_res), "bf-tmfifo"))
> > + return -EBUSY;
> > +
> > + fifo = devm_kzalloc(&pdev->dev, sizeof(*fifo), GFP_KERNEL);
> > + if (!fifo)
> > + return -ENOMEM;
> > +
> > + fifo->pdev = pdev;
> > + platform_set_drvdata(pdev, fifo);
> > +
> > + spin_lock_init(&fifo->spin_lock);
> > + INIT_WORK(&fifo->work, mlxbf_tmfifo_work_handler);
> > +
> > + timer_setup(&fifo->timer, mlxbf_tmfifo_timer, 0);
> > +
> > + for (i = 0; i < MLXBF_TM_IRQ_CNT; i++) {
> > + fifo->irq_info[i].index = i;
> > + fifo->irq_info[i].fifo = fifo;
>
> > + fifo->irq_info[i].irq = platform_get_irq(pdev, i);
>
>
> > + ret = devm_request_irq(&pdev->dev, fifo->irq_info[i].irq,
> > + mlxbf_tmfifo_irq_handler, 0,
> > + "tmfifo", &fifo->irq_info[i]);
> > + if (ret) {
> > + dev_err(&pdev->dev, "devm_request_irq failed\n");
> > + fifo->irq_info[i].irq = 0;
> > + return ret;
> > + }
> > + }
> > +
>
> > + fifo->rx_base = devm_ioremap(&pdev->dev, rx_res->start,
> > + resource_size(rx_res));
> > + if (!fifo->rx_base)
> > + return -ENOMEM;
> > +
> > + fifo->tx_base = devm_ioremap(&pdev->dev, tx_res->start,
> > + resource_size(tx_res));
> > + if (!fifo->tx_base)
> > + return -ENOMEM;
>
> Switch to devm_ioremap_resource().
> However, I think you probably need memremap().
Updated in v10 to use devm_ioremap_resource().
The map is just for several registers which is not meant to be
cache-able. Probably devm_ioremap_nocache() might make
more sense? I checked arm64/include/asm/io.h, looks like
ioremap/ioremap_nocache/ioremap_wt are defined the same
thing.
>
> > + mutex_init(&fifo->lock);
>
> Isn't too late for initializing this one?
It won't cause problem here due to the 'is_ready'
flag, but definitely better to move it ahead. Updated in v10.
>
>
> > +/* Device remove function. */
> > +static int mlxbf_tmfifo_remove(struct platform_device *pdev)
> > +{
> > + struct mlxbf_tmfifo *fifo = platform_get_drvdata(pdev);
> > +
>
> > + if (fifo)
>
> How is it possible to be not true?
Updated in v10. Removed.
>
> > + mlxbf_tmfifo_cleanup(fifo);
> > +
>
> > + platform_set_drvdata(pdev, NULL);
>
> Redundant.
Updated in v10. Removed.
>
> > +
> > + return 0;
> > +}
>
> > +MODULE_LICENSE("GPL");
>
> Is it correct?
Fixed in v10 and updated to MODULE_LICENSE("GPL v2");
>
> --
> With Best Regards,
> Andy Shevchenko
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