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 <20200212215717.9474-2-rentao.bupt@gmail.com>
Date:   Mon, 17 Feb 2020 10:18:11 +1030
From:   "Andrew Jeffery" <andrew@aj.id.au>
To:     "Tao Ren" <rentao.bupt@gmail.com>,
        "Felipe Balbi" <balbi@kernel.org>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        "Joel Stanley" <joel@jms.id.au>,
        "Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
        "Chunfeng Yun" <chunfeng.yun@mediatek.com>,
        "Colin King" <colin.king@canonical.com>,
        "Stephen Boyd" <swboyd@chromium.org>,
        "Rob Herring" <robh+dt@kernel.org>,
        "Mark Rutland" <mark.rutland@arm.com>, linux-usb@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org,
        "Tao Ren" <taoren@fb.com>
Subject: =?UTF-8?Q?Re:_[PATCH_v2_1/5]_usb:_gadget:_aspeed:_read_vhub_properties_f?=
 =?UTF-8?Q?rom_device_tree?=
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On Thu, 13 Feb 2020, at 08:27, rentao.bupt@gmail.com wrote:
> From: Tao Ren <rentao.bupt@gmail.com>
> 
> The patch introduces 2 DT properties ("aspeed,vhub-downstream-ports" and
> "aspeed,vhub-generic-endpoints") which replaces hardcoded port/endpoint
> number. It is to make it more convenient to add support for newer vhub
> revisions with different number of ports and endpoints.
> 
> Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
> Reviewed-by: Joel Stanley <joel@jms.id.au>
> ---
>  Changes in v2:
>    - removed ast_vhub_config structure and moved vhub port/endpoint
>      number into device tree.
> 
>  drivers/usb/gadget/udc/aspeed-vhub/core.c | 68 ++++++++++++++---------
>  drivers/usb/gadget/udc/aspeed-vhub/dev.c  | 30 +++++++---
>  drivers/usb/gadget/udc/aspeed-vhub/epn.c  |  4 +-
>  drivers/usb/gadget/udc/aspeed-vhub/hub.c  | 26 ++++++---
>  drivers/usb/gadget/udc/aspeed-vhub/vhub.h | 23 +++-----
>  5 files changed, 91 insertions(+), 60 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/aspeed-vhub/core.c 
> b/drivers/usb/gadget/udc/aspeed-vhub/core.c
> index 90b134d5dca9..d6f737fac4e2 100644
> --- a/drivers/usb/gadget/udc/aspeed-vhub/core.c
> +++ b/drivers/usb/gadget/udc/aspeed-vhub/core.c
> @@ -99,7 +99,7 @@ static irqreturn_t ast_vhub_irq(int irq, void *data)
>  {
>  	struct ast_vhub *vhub = data;
>  	irqreturn_t iret = IRQ_NONE;
> -	u32 istat;
> +	u32 i, istat;
>  
>  	/* Stale interrupt while tearing down */
>  	if (!vhub->ep0_bufs)
> @@ -121,10 +121,10 @@ static irqreturn_t ast_vhub_irq(int irq, void *data)
>  
>  	/* Handle generic EPs first */
>  	if (istat & VHUB_IRQ_EP_POOL_ACK_STALL) {
> -		u32 i, ep_acks = readl(vhub->regs + AST_VHUB_EP_ACK_ISR);
> +		u32 ep_acks = readl(vhub->regs + AST_VHUB_EP_ACK_ISR);
>  		writel(ep_acks, vhub->regs + AST_VHUB_EP_ACK_ISR);
>  
> -		for (i = 0; ep_acks && i < AST_VHUB_NUM_GEN_EPs; i++) {
> +		for (i = 0; ep_acks && i < vhub->max_epns; i++) {
>  			u32 mask = VHUB_EP_IRQ(i);
>  			if (ep_acks & mask) {
>  				ast_vhub_epn_ack_irq(&vhub->epns[i]);
> @@ -134,21 +134,11 @@ static irqreturn_t ast_vhub_irq(int irq, void *data)
>  	}
>  
>  	/* Handle device interrupts */
> -	if (istat & (VHUB_IRQ_DEVICE1 |
> -		     VHUB_IRQ_DEVICE2 |
> -		     VHUB_IRQ_DEVICE3 |
> -		     VHUB_IRQ_DEVICE4 |
> -		     VHUB_IRQ_DEVICE5)) {
> -		if (istat & VHUB_IRQ_DEVICE1)
> -			ast_vhub_dev_irq(&vhub->ports[0].dev);
> -		if (istat & VHUB_IRQ_DEVICE2)
> -			ast_vhub_dev_irq(&vhub->ports[1].dev);
> -		if (istat & VHUB_IRQ_DEVICE3)
> -			ast_vhub_dev_irq(&vhub->ports[2].dev);
> -		if (istat & VHUB_IRQ_DEVICE4)
> -			ast_vhub_dev_irq(&vhub->ports[3].dev);
> -		if (istat & VHUB_IRQ_DEVICE5)
> -			ast_vhub_dev_irq(&vhub->ports[4].dev);
> +	for (i = 0; i < vhub->max_ports; i++) {
> +		u32 dev_mask = VHUB_IRQ_DEVICE1 << i;
> +
> +		if (istat & dev_mask)
> +			ast_vhub_dev_irq(&vhub->ports[i].dev);
>  	}
>  
>  	/* Handle top-level vHub EP0 interrupts */
> @@ -182,7 +172,7 @@ static irqreturn_t ast_vhub_irq(int irq, void *data)
>  
>  void ast_vhub_init_hw(struct ast_vhub *vhub)
>  {
> -	u32 ctrl;
> +	u32 ctrl, port_mask, epn_mask;
>  
>  	UDCDBG(vhub,"(Re)Starting HW ...\n");
>  
> @@ -222,15 +212,20 @@ void ast_vhub_init_hw(struct ast_vhub *vhub)
>  	}
>  
>  	/* Reset all devices */
> -	writel(VHUB_SW_RESET_ALL, vhub->regs + AST_VHUB_SW_RESET);
> +	port_mask = GENMASK(vhub->max_ports, 1);
> +	writel(VHUB_SW_RESET_ROOT_HUB |
> +	       VHUB_SW_RESET_DMA_CONTROLLER |
> +	       VHUB_SW_RESET_EP_POOL |
> +	       port_mask, vhub->regs + AST_VHUB_SW_RESET);
>  	udelay(1);
>  	writel(0, vhub->regs + AST_VHUB_SW_RESET);
>  
>  	/* Disable and cleanup EP ACK/NACK interrupts */
> +	epn_mask = GENMASK(vhub->max_epns - 1, 0);
>  	writel(0, vhub->regs + AST_VHUB_EP_ACK_IER);
>  	writel(0, vhub->regs + AST_VHUB_EP_NACK_IER);
> -	writel(VHUB_EP_IRQ_ALL, vhub->regs + AST_VHUB_EP_ACK_ISR);
> -	writel(VHUB_EP_IRQ_ALL, vhub->regs + AST_VHUB_EP_NACK_ISR);
> +	writel(epn_mask, vhub->regs + AST_VHUB_EP_ACK_ISR);
> +	writel(epn_mask, vhub->regs + AST_VHUB_EP_NACK_ISR);
>  
>  	/* Default settings for EP0, enable HW hub EP1 */
>  	writel(0, vhub->regs + AST_VHUB_EP0_CTRL);
> @@ -273,7 +268,7 @@ static int ast_vhub_remove(struct platform_device *pdev)
>  		return 0;
>  
>  	/* Remove devices */
> -	for (i = 0; i < AST_VHUB_NUM_PORTS; i++)
> +	for (i = 0; i < vhub->max_ports; i++)
>  		ast_vhub_del_dev(&vhub->ports[i].dev);
>  
>  	spin_lock_irqsave(&vhub->lock, flags);
> @@ -295,7 +290,7 @@ static int ast_vhub_remove(struct platform_device *pdev)
>  	if (vhub->ep0_bufs)
>  		dma_free_coherent(&pdev->dev,
>  				  AST_VHUB_EP0_MAX_PACKET *
> -				  (AST_VHUB_NUM_PORTS + 1),
> +				  (vhub->max_ports + 1),
>  				  vhub->ep0_bufs,
>  				  vhub->ep0_bufs_dma);
>  	vhub->ep0_bufs = NULL;
> @@ -309,11 +304,32 @@ static int ast_vhub_probe(struct platform_device *pdev)
>  	struct ast_vhub *vhub;
>  	struct resource *res;
>  	int i, rc = 0;
> +	const struct device_node *np = pdev->dev.of_node;
>  
>  	vhub = devm_kzalloc(&pdev->dev, sizeof(*vhub), GFP_KERNEL);
>  	if (!vhub)
>  		return -ENOMEM;
>  
> +	rc = of_property_read_u32(np, "aspeed,vhub-downstream-ports",
> +				  &vhub->max_ports);
> +	if (rc < 0)
> +		return -ENODEV;

This breaks the driver for old devicetrees, or at the very least,
devicetrees without your subsequent two patches in the series.

I feel we shouldn't drop the built-in values for the 2400 and 2500, that
way we can fall back to them if the devicetree properties aren't present.

For the 2600 we can have a clean break and require the properties be
present (i.e. not hardcode the values in the driver for fallback) as there
aren't yet any devicetrees describing the device.

Andrew