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Message-ID: <alpine.LFD.2.00.1102281858240.2701@localhost6.localdomain6>
Date: Mon, 28 Feb 2011 19:33:05 +0100 (CET)
From: Thomas Gleixner <tglx@...utronix.de>
To: Sascha Hauer <s.hauer@...gutronix.de>
cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-fbdev@...r.kernel.org, Paul Mundt <lethal@...ux-sh.org>,
Samuel Ortiz <sameo@...ux.intel.com>
Subject: Re: [PATCH 3/8] Add a mfd IPUv3 driver
On Mon, 28 Feb 2011, Sascha Hauer wrote:
> +
> +static int ipu_use_count;
> +
> +static struct ipu_channel channels[64];
> +
> +struct ipu_channel *ipu_idmac_get(unsigned num)
> +{
> + struct ipu_channel *channel;
> +
> + dev_dbg(ipu_dev, "%s %d\n", __func__, num);
> +
> + if (num > 63)
>= ARRAY_SIZE(channels) or a sensible define please
> + return ERR_PTR(-ENODEV);
> +
> + mutex_lock(&ipu_channel_lock);
> +
> + channel = &channels[num];
> +
> + if (channel->busy) {
> + channel = ERR_PTR(-EBUSY);
> + goto out;
> + }
> +
> + channel->busy = 1;
> + channel->num = num;
> +
> +out:
> + mutex_unlock(&ipu_channel_lock);
> +
> + return channel;
> +}
> +EXPORT_SYMBOL(ipu_idmac_get);
EXPORT_SYMBOL_GPL all over the place
> +void ipu_idmac_put(struct ipu_channel *channel)
> +{
> + dev_dbg(ipu_dev, "%s %d\n", __func__, channel->num);
Do we really need this debug stuff in all these functions ?
> + mutex_lock(&ipu_channel_lock);
> +
> + channel->busy = 0;
> +
> + mutex_unlock(&ipu_channel_lock);
> +}
> +EXPORT_SYMBOL(ipu_idmac_put);
> +
Also exported functions want a proper kerneldoc comment.
> +void ipu_idmac_set_double_buffer(struct ipu_channel *channel, bool doublebuffer)
> +static LIST_HEAD(ipu_irq_handlers);
> +
> +static void ipu_irq_update_irq_mask(void)
> +{
> + struct ipu_irq_handler *handler;
> + int i;
> +
> + DECLARE_IPU_IRQ_BITMAP(irqs);
Why the hell do we need this? It's a bog standard bitmap, right ?
> + bitmap_zero(irqs, IPU_IRQ_COUNT);
> +
> + list_for_each_entry(handler, &ipu_irq_handlers, list)
> + bitmap_or(irqs, irqs, handler->ipu_irqs, IPU_IRQ_COUNT);
> +
> + for (i = 0; i < BITS_TO_LONGS(IPU_IRQ_COUNT); i++)
> + ipu_cm_write(irqs[i], IPU_INT_CTRL(i + 1));
> +}
> +static void ipu_completion_handler(unsigned long *bitmask, void *context)
> +{
> + struct completion *completion = context;
> +
> + complete(completion);
> +}
> +
> +int ipu_wait_for_interrupt(int interrupt, int timeout_ms)
> +{
> + struct ipu_irq_handler handler;
> + DECLARE_COMPLETION_ONSTACK(completion);
> + int ret;
> +
> + bitmap_zero(handler.ipu_irqs, IPU_IRQ_COUNT);
> + bitmap_set(handler.ipu_irqs, interrupt, 1);
> +
> + ipu_cm_write(1 << (interrupt % 32), IPU_INT_STAT(interrupt / 32 + 1));
> +
> + handler.handler = ipu_completion_handler;
> + handler.context = &completion;
> + ipu_irq_add_handler(&handler);
> +
> + ret = wait_for_completion_timeout(&completion,
> + msecs_to_jiffies(timeout_ms));
> +
> + ipu_irq_remove_handler(&handler);
> +
> + if (ret > 0)
> + ret = 0;
> + else
> + ret = -ETIMEDOUT;
> +
> + return ret;
return ret > 0 ? 0 : -ETIMEDOUT;
perhaps ?
> +}
> +EXPORT_SYMBOL(ipu_wait_for_interrupt);
> +
> +static irqreturn_t ipu_irq_handler(int irq, void *desc)
> +{
> + DECLARE_IPU_IRQ_BITMAP(status);
> + struct ipu_irq_handler *handler;
> + int i;
> +
> + for (i = 0; i < BITS_TO_LONGS(IPU_IRQ_COUNT); i++) {
> + status[i] = ipu_cm_read(IPU_INT_STAT(i + 1));
> + ipu_cm_write(status[i], IPU_INT_STAT(i + 1));
> + }
> +
> + list_for_each_entry(handler, &ipu_irq_handlers, list) {
> + DECLARE_IPU_IRQ_BITMAP(tmp);
> + if (bitmap_and(tmp, status, handler->ipu_irqs, IPU_IRQ_COUNT))
> + handler->handler(tmp, handler->context);
> + }
And what protects the list walk? Just the fact that this is a UP
machine?
> +void ipu_put(void)
> +{
> + mutex_lock(&ipu_channel_lock);
> +
> + ipu_use_count--;
> +
> + if (ipu_use_count == 0)
> + clk_disable(ipu_clk);
> +
> + if (ipu_use_count < 0) {
> + dev_err(ipu_dev, "ipu use count < 0\n");
This wants to be a WARN_ON(ipu_use_count < 0) so you get some
information which code is calling this.
> + ipu_use_count = 0;
> + }
> +
> + mutex_unlock(&ipu_channel_lock);
> +}
> +static int __devinit ipu_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + unsigned long ipu_base;
> + int ret, irq1, irq2;
> +
> + /* There can be only one */
> + if (ipu_dev)
> + return -EBUSY;
> +
> + spin_lock_init(&ipu_lock);
> +
> + ipu_dev = &pdev->dev;
> +
> + irq1 = platform_get_irq(pdev, 0);
> + irq2 = platform_get_irq(pdev, 1);
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> + if (!res || irq1 < 0 || irq2 < 0)
> + return -ENODEV;
> +
> + ipu_base = res->start;
> +
> + ipu_cm_reg = ioremap(ipu_base + IPU_CM_REG_BASE, PAGE_SIZE);
> + if (!ipu_cm_reg) {
> + ret = -ENOMEM;
> + goto failed_ioremap1;
> + }
> +
> + ipu_idmac_reg = ioremap(ipu_base + IPU_IDMAC_REG_BASE, PAGE_SIZE);
> + if (!ipu_idmac_reg) {
> + ret = -ENOMEM;
> + goto failed_ioremap2;
> + }
> +
> + ipu_clk = clk_get(&pdev->dev, "ipu");
> + if (IS_ERR(ipu_clk)) {
> + ret = PTR_ERR(ipu_clk);
> + dev_err(&pdev->dev, "clk_get failed with %d", ret);
> + goto failed_clk_get;
> + }
> +
> + ipu_get();
> +
> + ret = request_irq(irq1, ipu_irq_handler, IRQF_DISABLED, pdev->name,
> + &pdev->dev);
s/IRQF_DISABLED/0/ We run all handlers with interrupts disabled
nowadays.
> + ret = ipu_submodules_init(pdev, ipu_base, ipu_clk);
> + if (ret)
> + goto failed_submodules_init;
> +
> + /* Set sync refresh channels as high priority */
> + ipu_idmac_write(0x18800000, IDMAC_CHA_PRI(0));
Hmm, this random prio setting here is odd.
> + ret = ipu_add_client_devices(pdev);
> + if (ret) {
> + dev_err(&pdev->dev, "adding client devices failed with %d\n", ret);
> + goto failed_add_clients;
> + }
White space damage.
> + ret = ipu_wait_for_interrupt(irq, 50);
> + if (ret)
> + return;
> +
> + /* Wait for DC triple buffer to empty */
> + if (dc_channels[dc_chan].di == 0)
> + while ((__raw_readl(DC_STAT) & 0x00000002)
> + != 0x00000002) {
> + msleep(2);
> + timeout -= 2;
> + if (timeout <= 0)
> + break;
So we poll stuff which is updated from some other function ?
> + }
> + else if (dc_channels[dc_chan].di == 1)
> + while ((__raw_readl(DC_STAT) & 0x00000020)
> + != 0x00000020) {
> + msleep(2);
> + timeout -= 2;
> + if (timeout <= 0)
> + break;
Ditto
> + }
Thanks,
tglx
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