From: Arnd Bergmann <arnd@arndb.de>
To: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linus.walleij@stericsson.com,
Russell King <linux@arm.linux.org.uk>,
Chris Ball <cjb@laptop.org>,
linux-mmc@vger.kernel.org
Subject: Re: [PATCH] mmc: mmci: Allow MMCI to request channels with information acquired from DT
Date: Wed, 17 Apr 2013 17:31:56 +0200 [thread overview]
Message-ID: <201304171731.56292.arnd@arndb.de> (raw)
In-Reply-To: <20130417150437.GA3137@gmail.com>
On Wednesday 17 April 2013, Lee Jones wrote:
> > This looks unnecessarily complex.
>
> That thought did cross my mind.
>
> > Why not just do dma_request_slave_channel_compat() unconditionally here?
>
> So how about something like this instead, as it keeps the current
> semantics, and only differs in the case of DT.
Yes, looks better.
> @@ -298,14 +298,16 @@ static void mmci_init_sg(struct mmci_host *host, struct mmc_data *data)
> * no custom DMA interfaces are supported.
> */
> #ifdef CONFIG_DMA_ENGINE
> -static void mmci_dma_setup(struct mmci_host *host)
> +static void mmci_dma_setup(struct amba_device *dev,
> + struct mmci_host *host)
> {
> + struct device_node *np = dev->dev.of_node;
> struct mmci_platform_data *plat = host->plat;
> const char *rxname, *txname;
> dma_cap_mask_t mask;
>
> - if (!plat || !plat->dma_filter) {
> - dev_info(mmc_dev(host->mmc), "no DMA platform data\n");
> + if (!(plat && plat->dma_filter) && !np) {
> + dev_info(mmc_dev(host->mmc), "no DMA platform data or DT\n");
> return;
> }
I think you can further simplify this, given that in the DT case we always
allocate a zeroed mmci_platform_data for host->plat, so !plat cannot happen
when we get here.
> @@ -321,19 +323,21 @@ static void mmci_dma_setup(struct mmci_host *host)
> * attempt to use it bidirectionally, however if it is
> * is specified but cannot be located, DMA will be disabled.
> */
> - if (plat->dma_rx_param) {
> - host->dma_rx_channel = dma_request_channel(mask,
> - plat->dma_filter,
> - plat->dma_rx_param);
> + if ((plat && plat->dma_rx_param) || np) {
> + host->dma_rx_channel = dma_request_slave_channel_compat(mask,
> + (plat) ? plat->dma_filter : NULL,
> + (plat) ? plat->dma_rx_param : NULL,
> + &dev->dev, "rx");
> /* E.g if no DMA hardware is present */
> if (!host->dma_rx_channel)
> dev_err(mmc_dev(host->mmc), "no RX DMA channel\n");
And based on that, you can unconditionally pass plat->dma_filter and
plat->dma_rx_param here. In case of DT, they will be NULL, and they
will not be used either.
Arnd
next prev parent reply other threads:[~2013-04-17 15:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-17 13:32 [PATCH] mmc: mmci: Allow MMCI to request channels with information acquired from DT Lee Jones
2013-04-17 13:50 ` Arnd Bergmann
2013-04-17 15:04 ` Lee Jones
2013-04-17 15:31 ` Arnd Bergmann [this message]
2013-04-18 8:02 ` Lee Jones
2013-04-18 8:15 ` Russell King - ARM Linux
2013-04-18 9:25 ` Arnd Bergmann
2013-04-18 9:30 ` Russell King - ARM Linux
2013-04-18 8:21 ` Ulf Hansson
2013-04-24 10:58 Lee Jones
2013-04-30 13:01 ` Linus Walleij
2013-04-30 13:12 ` Lee Jones
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