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    SubjectRe: [PATCH 3/7] dmaengine: st_fdma: Add STMicroelectronics FDMA engine driver support
    Hi Vinod,

    Thanks for reviewing.

    On Wed, 19 Aug 2015, Vinod Koul wrote:

    > On Wed, Jul 08, 2015 at 05:11:24PM +0100, Peter Griffin wrote:
    > > +static int
    > > +st_fdma_elf_sanity_check(struct st_fdma_dev *fdev, const struct firmware *fw)
    > > +{
    > > + const char *fw_name = fdev->pdata->fw_name;
    > > + struct elf32_hdr *ehdr;
    > > + char class;
    > > +
    > > + if (!fw) {
    > > + dev_err(fdev->dev, "failed to load %s\n", fw_name);
    > > + return -EINVAL;
    > > + }
    > > +
    > > + if (fw->size < sizeof(struct elf32_hdr)) {
    > sizeof(*ehdr) ?

    Ok fixed in v2.

    >
    > > + dev_err(fdev->dev, "Image is too small\n");
    > > + return -EINVAL;
    > > + }
    > > +
    > > + ehdr = (struct elf32_hdr *)fw->data;
    > > +
    > > + /* We only support ELF32 at this point */
    > > + class = ehdr->e_ident[EI_CLASS];
    > > + if (class != ELFCLASS32) {
    > > + dev_err(fdev->dev, "Unsupported class: %d\n", class);
    > > + return -EINVAL;
    > > + }
    > > +
    > > + if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
    > > + dev_err(fdev->dev, "Unsupported firmware endianness\n");
    > would be worth printing the value for debug

    Fixed in v2

    >
    > > + return -EINVAL;
    > > + }
    > > +
    > > + if (fw->size < ehdr->e_shoff + sizeof(struct elf32_shdr)) {
    > > + dev_err(fdev->dev, "Image is too small\n");
    > Again printing size helps when you get a log trace and have no idea why size
    > was small. Similar one other places

    Fixed in v2

    >
    >
    > > + dst = st_fdma_seg_to_mem(fdev, da, memsz);
    > > + if (!dst) {
    > > + dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
    > > + break;
    > > + }
    > > +
    > > + if (phdr->p_filesz)
    > > + memcpy(dst, elf_data + phdr->p_offset, filesz);
    > > +
    > > + if (memsz > filesz)
    > > + memset(dst + filesz, 0, memsz - filesz);
    > > +
    > > + mem_loaded++;
    > > + }
    > > +
    > > + return (mem_loaded != fdev->drvdata->num_mem) ? -EINVAL : 0;
    > so you are not expecting any segment with PT_LOAD otherwise this check will
    > fail as num_mem is assigned from e_phnum.

    That is correct.

    > Also perhaps EIO will be better return?

    Updated to -EIO in v2.

    >
    > > +}
    > > +
    > > +static void st_fdma_enable(struct st_fdma_dev *fdev)
    > > +{
    > > + unsigned long hw_id, hw_ver, fw_rev;
    > > + u32 val;
    > > +
    > > + /* disable CPU pipeline clock & reset cpu pipeline */
    > > + val = FDMA_CLK_GATE_DIS | FDMA_CLK_GATE_RESET;
    > > + fdma_write(fdev, val, CLK_GATE);
    >
    > empty line here

    Removed in v2.

    >
    > > + /* disable SLIM core STBus sync */
    > > + fdma_write(fdev, FDMA_STBUS_SYNC_DIS, STBUS_SYNC);
    > > + /* enable cpu pipeline clock */
    > > + fdma_write(fdev, !FDMA_CLK_GATE_DIS, CLK_GATE);
    > > +
    > > + /* clear int & cmd mailbox */
    > > + fdma_write(fdev, ~0UL, INT_CLR);
    > > + fdma_write(fdev, ~0UL, CMD_CLR);
    >
    > here too

    Removed in v2.
    >
    > > +static int st_fdma_get_fw(struct st_fdma_dev *fdev)
    > > +{
    > > + int ret;
    > > +
    > > + init_completion(&fdev->fw_ack);
    > > + atomic_set(&fdev->fw_loaded, 0);
    > > +
    > > + ret = request_firmware_nowait(THIS_MODULE, FW_ACTION_HOTPLUG,
    > > + fdev->pdata->fw_name, fdev->dev,
    > > + GFP_KERNEL, fdev, st_fdma_fw_cb);
    >
    > Isn't doing this in device probe too stringent and holding up load...

    No I don't think so, as we are using the _nowait variant which is
    asynchronous and sleeps for the smallest period possible so as not
    to increase boot time of built-in code.

    We could use GFP_ATOMIC which means request_firmware_nowait can't sleep
    at all. Although no other drivers which use request_firmware_nowait
    in their probe functions do that which I can see.

    >
    > > + fdesc = st_fdma_alloc_desc(fchan, sg_len);
    > > + if (!fdesc) {
    > > + dev_err(fchan->fdev->dev, "no memory for desc\n");
    > > + return NULL;
    > > + }
    > > +
    > > + fdesc->iscyclic = false;
    > > +
    > > + for_each_sg(sgl, sg, sg_len, i) {
    > > + hw_node = fdesc->node[i].desc;
    > > +
    > > + hw_node->next = fdesc->node[(i + 1) % sg_len].pdesc;
    > > + hw_node->control = NODE_CTRL_REQ_MAP_DREQ(fchan->dreq_line);
    > > +
    > > + if (direction == DMA_MEM_TO_DEV) {
    > > + hw_node->control |= NODE_CTRL_SRC_INCR;
    > > + hw_node->control |= NODE_CTRL_DST_STATIC;
    > > + hw_node->saddr = sg_dma_address(sg);
    > > + hw_node->daddr = fchan->cfg.dev_addr;
    > > + } else {
    > > + hw_node->control |= NODE_CTRL_SRC_STATIC;
    > > + hw_node->control |= NODE_CTRL_DST_INCR;
    > > + hw_node->saddr = fchan->cfg.dev_addr;
    > > + hw_node->daddr = sg_dma_address(sg);
    > > + }
    > > +
    > > + hw_node->nbytes = sg_dma_len(sg);
    > > + hw_node->generic.length = sg_dma_len(sg);
    > > + hw_node->generic.sstride = 0;
    > > + hw_node->generic.dstride = 0;
    >
    > This looks quite similar to previous one, I think some bits can be reused

    Will abstract out common parts in v2.

    >
    > > +static int st_fdma_slave_config(struct dma_chan *chan,
    > > + struct dma_slave_config *slave_cfg)
    > > +{
    > > + u32 maxburst = 0, addr = 0;
    > > + enum dma_slave_buswidth width;
    > > + struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
    > > + int ch_id = fchan->vchan.chan.chan_id;
    > > + struct st_fdma_dev *fdev = fchan->fdev;
    > > +
    > > + if (slave_cfg->direction == DMA_DEV_TO_MEM) {
    >
    > This is depreciated, you can't use direction here. Please save the fields and
    > then use them in prep_ call

    Ok, will save the fields and use in prep_ calls in v2.

    >
    > Also this is quite big patch, consider splitting it up for faster review

    Will split into smaller patches in v2.

    regards,

    Peter.


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