Hi Carl,

On Mon, Oct 08, 2018 at 05:49:42PM +0800, Carl Huang wrote:
> ath10k_pci_diag_write_mem may allocate big size of the dma memory
> based on the parameter nbytes. Take firmware diag download as
> example, the biggest size is about 500K. In some systems, the
> allocation is likely to fail because it can't acquire such a large
> contiguous dma memory.
> 
> The fix is to allocate a small size dma memory. In the loop,
> driver copies the data to the allocated dma memory and writes to
> the destination until all the data is written.
> 
> Tested with QCA6174 PCI with
> firmware-6.bin_WLAN.RM.4.4.1-00119-QCARMSWP-1, this also affects
> QCA9377 PCI.
> 
> Signed-off-by: Carl Huang <cjhu...@codeaurora.org>

Thanks for the patch! With one small comment, I think this otherwise
looks good, so feel free to add my:

Reviewed-by: Brian Norris <briannor...@chomium.org>

> ---
>  drivers/net/wireless/ath/ath10k/pci.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/pci.c 
> b/drivers/net/wireless/ath/ath10k/pci.c
> index 873dbb6..1872671 100644
> --- a/drivers/net/wireless/ath/ath10k/pci.c
> +++ b/drivers/net/wireless/ath/ath10k/pci.c
> @@ -1071,7 +1071,7 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 
> address,
>       struct ath10k_ce *ce = ath10k_ce_priv(ar);
>       int ret = 0;
>       u32 *buf;
> -     unsigned int completed_nbytes, orig_nbytes, remaining_bytes;
> +     unsigned int completed_nbytes, alloc_nbytes, remaining_bytes;
>       struct ath10k_ce_pipe *ce_diag;
>       void *data_buf = NULL;
>       u32 ce_data;    /* Host buffer address in CE space */

^^ I don't think this is needed any more.

> @@ -1088,9 +1088,10 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 
> address,
>        *   1) 4-byte alignment
>        *   2) Buffer in DMA-able space
>        */
> -     orig_nbytes = nbytes;
> +     alloc_nbytes = min_t(unsigned int, nbytes, DIAG_TRANSFER_LIMIT);
> +
>       data_buf = (unsigned char *)dma_alloc_coherent(ar->dev,
> -                                                    orig_nbytes,
> +                                                    alloc_nbytes,
>                                                      &ce_data_base,
>                                                      GFP_ATOMIC);
>       if (!data_buf) {
> @@ -1098,9 +1099,6 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 
> address,
>               goto done;
>       }
>  
> -     /* Copy caller's data to allocated DMA buf */
> -     memcpy(data_buf, data, orig_nbytes);
> -
>       /*
>        * The address supplied by the caller is in the
>        * Target CPU virtual address space.
> @@ -1113,12 +1111,15 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 
> address,
>        */
>       address = ath10k_pci_targ_cpu_to_ce_addr(ar, address);
>  
> -     remaining_bytes = orig_nbytes;
> +     remaining_bytes = nbytes;
>       ce_data = ce_data_base;

Because you no longer need to increment 'ce_data', you can just pass
'ce_data_base' to ath10k_ce_send_nolock() now.

Regards,
Brian

>       while (remaining_bytes) {
>               /* FIXME: check cast */
>               nbytes = min_t(int, remaining_bytes, DIAG_TRANSFER_LIMIT);
>  
> +             /* Copy caller's data to allocated DMA buf */
> +             memcpy(data_buf, data, nbytes);
> +
>               /* Set up to receive directly into Target(!) address */
>               ret = ce_diag->ops->ce_rx_post_buf(ce_diag, &address, address);
>               if (ret != 0)
> @@ -1171,12 +1172,12 @@ int ath10k_pci_diag_write_mem(struct ath10k *ar, u32 
> address,
>  
>               remaining_bytes -= nbytes;
>               address += nbytes;
> -             ce_data += nbytes;
> +             data += nbytes;
>       }
>  
>  done:
>       if (data_buf) {
> -             dma_free_coherent(ar->dev, orig_nbytes, data_buf,
> +             dma_free_coherent(ar->dev, alloc_nbytes, data_buf,
>                                 ce_data_base);
>       }
>  
> -- 
> 2.7.4
> 

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