Messages in this thread | | | Subject | Re: [PATCH v2] spi: qup: Add DMA capabilities | From | "Ivan T. Ivanov" <> | Date | Tue, 24 Feb 2015 19:11:56 +0200 |
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Hi Stan,
Sorry I didn't saw this first look.
On Tue, 2015-02-24 at 15:00 +0200, Stanimir Varbanov wrote:
<snip>
> > +static bool spi_qup_can_dma(struct spi_master *master, struct spi_device *spi, > + struct spi_transfer *xfer) > +{ > + struct spi_qup *qup = spi_master_get_devdata(master); > + size_t dma_align = dma_get_cache_alignment(); > + int n_words, w_size; > + > + qup->dma_available = 0; > + > + if (xfer->rx_buf && xfer->len % qup->in_blk_sz) > + return false; > + > + if (xfer->tx_buf && xfer->len % qup->out_blk_sz) > + return false; > +
Actually we can end up here with tx_buf or rx_buf to be NULL. Which voids my previous comments about these pointers.
It will be simpler if you just check transfer length.
And better return false if both are NULL.
> + if (IS_ERR_OR_NULL(master->dma_rx) || IS_ERR_OR_NULL(master->dma_tx)) > + return false; > + > + if (!IS_ALIGNED((size_t)xfer->tx_buf, dma_align) || > + !IS_ALIGNED((size_t)xfer->rx_buf, dma_align)) > + return false;
Testing NULL for alignment is fine, right?
> + w_size = spi_qup_get_word_sz(xfer); > + n_words = xfer->len / w_size; > + > + /* will use fifo mode */ > + if (n_words <= (qup->in_fifo_sz / sizeof(u32))) > + return false; > + > + qup->dma_available = 1; > + > + return true; > +} > +
Regards, Ivan
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