Re: [PATCH v4] mmc: moxart: fix probe logic

Ulf Hansson
2015-02-04T08:40:52Z

On 3 February 2015 at 16:55, Jonas Jensen <jonas.jensen@gmail.com> wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Jonas Jensen wanted to submit a patch for these, but apparently
> forgot about it. I stumbled over this symptom first:
>
> drivers/built-in.o: In function `moxart_probe':
> :(.text+0x2af128): undefined reference to `of_dma_request_slave_channel'
>
> This is because of_dma_request_slave_channel is an internal helper
> and not exported to loadable module. I'm changing the driver to
> use dma_request_slave_channel_reason() instead.
>
> Further problems from inspection:
>
> * The remove function must not call kfree on the host pointer,
> because it is allocated together with the mmc_host.
>
> * The clock is never released
>
> * The dma_cap_mask_t is completely unused and can be removed
>
> * deferred probing does not work if the dma driver is loaded
> after the mmc driver.
>
> This patch should fix all of the above.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>

Thanks! Applied for next, with minor fixes - see below.

Kind regards
Uffe

> ---
>
> Notes:
> This is a forward of Arnd's v2 patch.
>
> v2: do not call clk_put() on an error pointer
> v3: fix NULL dereference on host->clk
> v4: rework to use devm_clk_get()
>
> Applies to next-20150113
>
> drivers/mmc/host/moxart-mmc.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/mmc/host/moxart-mmc.c b/drivers/mmc/host/moxart-mmc.c
> index d2a1ef6..6cb4053 100644
> --- a/drivers/mmc/host/moxart-mmc.c
> +++ b/drivers/mmc/host/moxart-mmc.c
> @@ -17,6 +17,7 @@
> #include <linux/init.h>
> #include <linux/platform_device.h>
> #include <linux/delay.h>
> +#include <linux/errno.h>
> #include <linux/interrupt.h>
> #include <linux/blkdev.h>
> #include <linux/dma-mapping.h>
> @@ -562,7 +563,6 @@ static int moxart_probe(struct platform_device *pdev)
> struct dma_slave_config cfg;
> struct clk *clk;
> void __iomem *reg_mmc;
> - dma_cap_mask_t mask;
> int irq, ret;
> u32 i;
>
> @@ -586,9 +586,9 @@ static int moxart_probe(struct platform_device *pdev)
> goto out;
> }
>
> - clk = of_clk_get(node, 0);
> + clk = devm_clk_get(dev, 0);

Changed to:
clk = devm_clk_get(dev, NULL);

> if (IS_ERR(clk)) {
> - dev_err(dev, "of_clk_get failed\n");
> + dev_err(dev, "devm_clk_get failed\n");

No need to print this, handled by clock framework.

> ret = PTR_ERR(clk);
> goto out;
> }
> @@ -603,9 +603,6 @@ static int moxart_probe(struct platform_device *pdev)
> if (ret)
> goto out;
>
> - dma_cap_zero(mask);
> - dma_cap_set(DMA_SLAVE, mask);
> -
> host = mmc_priv(mmc);
> host->mmc = mmc;
> host->base = reg_mmc;
> @@ -613,8 +610,8 @@ static int moxart_probe(struct platform_device *pdev)
> host->timeout = msecs_to_jiffies(1000);
> host->sysclk = clk_get_rate(clk);
> host->fifo_width = readl(host->base + REG_FEATURE) << 2;
> - host->dma_chan_tx = of_dma_request_slave_channel(node, "tx");
> - host->dma_chan_rx = of_dma_request_slave_channel(node, "rx");
> + host->dma_chan_tx = dma_request_slave_channel_reason(dev, "tx");
> + host->dma_chan_rx = dma_request_slave_channel_reason(dev, "rx");
>
> spin_lock_init(&host->lock);
>
> @@ -624,6 +621,11 @@ static int moxart_probe(struct platform_device *pdev)
> mmc->ocr_avail = 0xffff00; /* Support 2.0v - 3.6v power. */
>
> if (IS_ERR(host->dma_chan_tx) || IS_ERR(host->dma_chan_rx)) {
> + if (PTR_ERR(host->dma_chan_tx) == -EPROBE_DEFER ||
> + PTR_ERR(host->dma_chan_rx) == -EPROBE_DEFER) {
> + ret = -EPROBE_DEFER;
> + goto out;
> + }
> dev_dbg(dev, "PIO mode transfer enabled\n");
> host->have_dma = false;
> } else {
> @@ -702,9 +704,6 @@ static int moxart_remove(struct platform_device *pdev)
> writel(readl(host->base + REG_CLOCK_CONTROL) | CLK_OFF,
> host->base + REG_CLOCK_CONTROL);
> }
> -
> - kfree(host);
> -
> return 0;
> }
>
> --
> 1.8.2.1
>