| Message ID | 1417183686-31481-5-git-send-email-ludovic.desroches@atmel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Let's look at the resulting code: On Fri, Nov 28, 2014 at 03:08:06PM +0100, Ludovic Desroches wrote: > +static int atmci_configure_dma(struct atmel_mci *host) > { > + int ret = 0; > > + host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx"); > + if (IS_ERR(host->dma.chan)) > + return PTR_ERR(host->dma.chan); > + > + dev_info(&host->pdev->dev, "using %s for DMA transfers\n", > + dma_chan_name(host->dma.chan)); > + > + host->dma_conf.src_addr = host->mapbase + ATMCI_RDR; > + host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; > + host->dma_conf.src_maxburst = 1; > + host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR; > + host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; > + host->dma_conf.dst_maxburst = 1; > + host->dma_conf.device_fc = false; > + > + return ret; > } I think you can clean this up a little further - what do you notice about the value of "ret" here?
On Fri, Nov 28, 2014 at 02:19:03PM +0000, Russell King - ARM Linux wrote: > Let's look at the resulting code: > > On Fri, Nov 28, 2014 at 03:08:06PM +0100, Ludovic Desroches wrote: > > +static int atmci_configure_dma(struct atmel_mci *host) > > { > > + int ret = 0; > > > > + host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx"); > > + if (IS_ERR(host->dma.chan)) > > + return PTR_ERR(host->dma.chan); > > + > > + dev_info(&host->pdev->dev, "using %s for DMA transfers\n", > > + dma_chan_name(host->dma.chan)); > > + > > + host->dma_conf.src_addr = host->mapbase + ATMCI_RDR; > > + host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; > > + host->dma_conf.src_maxburst = 1; > > + host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR; > > + host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; > > + host->dma_conf.dst_maxburst = 1; > > + host->dma_conf.device_fc = false; > > + > > + return ret; > > } > > I think you can clean this up a little further - what do you notice > about the value of "ret" here? I think I see what you mean :) The fix I have merged for this patch makes ret useless. > > -- > FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up > according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c index 00f6088..0a96819 100644 --- a/drivers/mmc/host/atmel-mci.c +++ b/drivers/mmc/host/atmel-mci.c @@ -2272,29 +2272,26 @@ static void atmci_cleanup_slot(struct atmel_mci_slot *slot, mmc_free_host(slot->mmc); } -static bool atmci_configure_dma(struct atmel_mci *host) +static int atmci_configure_dma(struct atmel_mci *host) { - if (host == NULL) - return false; + int ret = 0; - host->dma.chan = dma_request_slave_channel(&host->pdev->dev, "rxtx"); - if (!host->dma.chan) { - dev_warn(&host->pdev->dev, "no DMA channel available\n"); - return false; - } else { - dev_info(&host->pdev->dev, - "using %s for DMA transfers\n", - dma_chan_name(host->dma.chan)); - - host->dma_conf.src_addr = host->mapbase + ATMCI_RDR; - host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; - host->dma_conf.src_maxburst = 1; - host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR; - host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; - host->dma_conf.dst_maxburst = 1; - host->dma_conf.device_fc = false; - return true; - } + host->dma.chan = dma_request_slave_channel_reason(&host->pdev->dev, "rxtx"); + if (IS_ERR(host->dma.chan)) + return PTR_ERR(host->dma.chan); + + dev_info(&host->pdev->dev, "using %s for DMA transfers\n", + dma_chan_name(host->dma.chan)); + + host->dma_conf.src_addr = host->mapbase + ATMCI_RDR; + host->dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + host->dma_conf.src_maxburst = 1; + host->dma_conf.dst_addr = host->mapbase + ATMCI_TDR; + host->dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + host->dma_conf.dst_maxburst = 1; + host->dma_conf.device_fc = false; + + return ret; } /* @@ -2411,7 +2408,10 @@ static int atmci_probe(struct platform_device *pdev) /* Get MCI capabilities and set operations according to it */ atmci_get_cap(host); - if (atmci_configure_dma(host)) { + ret = atmci_configure_dma(host); + if (ret == -EPROBE_DEFER) + goto err_dma_probe_defer; + if (ret == 0) { host->prepare_data = &atmci_prepare_data_dma; host->submit_data = &atmci_submit_data_dma; host->stop_transfer = &atmci_stop_transfer_dma; @@ -2496,8 +2496,9 @@ err_init_slot: pm_runtime_put_noidle(&pdev->dev); del_timer_sync(&host->timer); - if (host->dma.chan) + if (!IS_ERR(host->dma.chan)) dma_release_channel(host->dma.chan); +err_dma_probe_defer: free_irq(irq, host); return ret; } @@ -2523,7 +2524,7 @@ static int atmci_remove(struct platform_device *pdev) atmci_readl(host, ATMCI_SR); del_timer_sync(&host->timer); - if (host->dma.chan) + if (!IS_ERR(host->dma.chan)) dma_release_channel(host->dma.chan); free_irq(platform_get_irq(pdev, 0), host);
Return probe defer if requesting a dma channel without a dma controller probed. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> --- drivers/mmc/host/atmel-mci.c | 49 ++++++++++++++++++++++---------------------- 1 file changed, 25 insertions(+), 24 deletions(-)