Re: [PATCHv1 2/2] usb: gadget: add udc driver for max3420

Felipe Balbi
2019-12-10T07:13:48Z

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Hi,

jassisinghbrar@gmail.com writes:
> From: Jassi Brar <jaswinder.singh@linaro.org>
>
> The MAX3420 is USB2.0 only, UDC-over-SPI controller. This driver
> also supports the peripheral mode of MAX3421.
>
> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
> ---
> drivers/usb/gadget/udc/Kconfig | 10 +
> drivers/usb/gadget/udc/Makefile | 1 +
> drivers/usb/gadget/udc/max3420_udc.c | 1334 ++++++++++++++++++++++++++
> 3 files changed, 1345 insertions(+)
> create mode 100644 drivers/usb/gadget/udc/max3420_udc.c
>
> diff --git a/drivers/usb/gadget/udc/Kconfig b/drivers/usb/gadget/udc/Kconfig
> index ae70ce29d5e4..702cf1547c37 100644
> --- a/drivers/usb/gadget/udc/Kconfig
> +++ b/drivers/usb/gadget/udc/Kconfig
> @@ -441,6 +441,16 @@ config USB_GADGET_XILINX
> dynamically linked module called "udc-xilinx" and force all
> gadget drivers to also be dynamically linked.
>
> +config USB_MAX3420_UDC
> + tristate "MAX3420 (USB-over-SPI) support"
> + depends on SPI
> + help
> + The Maxim MAX3420 chip supports USB2.0 full-speed peripheral mode.
> + The MAX3420 is run by SPI interface, and hence the dependency.
> +
> + To compile this driver as a module, choose M here: the module will
> + be called max3420_udc
> +
> config USB_TEGRA_XUDC
> tristate "NVIDIA Tegra Superspeed USB 3.0 Device Controller"
> depends on ARCH_TEGRA || COMPILE_TEST
> diff --git a/drivers/usb/gadget/udc/Makefile b/drivers/usb/gadget/udc/Makefile
> index f6777e654a8e..f5a7ce28aecd 100644
> --- a/drivers/usb/gadget/udc/Makefile
> +++ b/drivers/usb/gadget/udc/Makefile
> @@ -42,3 +42,4 @@ obj-$(CONFIG_USB_GADGET_XILINX) += udc-xilinx.o
> obj-$(CONFIG_USB_SNP_UDC_PLAT) += snps_udc_plat.o
> obj-$(CONFIG_USB_ASPEED_VHUB) += aspeed-vhub/
> obj-$(CONFIG_USB_BDC_UDC) += bdc/
> +obj-$(CONFIG_USB_MAX3420_UDC) += max3420_udc.o
> diff --git a/drivers/usb/gadget/udc/max3420_udc.c b/drivers/usb/gadget/udc/max3420_udc.c
> new file mode 100644
> index 000000000000..0213255c4b9a
> --- /dev/null
> +++ b/drivers/usb/gadget/udc/max3420_udc.c
> @@ -0,0 +1,1337 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * MAX3420 Device Controller driver for USB.
> + *
> + * Author: Jaswinder Singh Brar <jaswinder.singh@linaro.org>
> + * (C) Copyright 2019 Linaro Ltd
> + *
> + * Based on:
> + * o MAX3420E datasheet
> + * http://datasheets.maximintegrated.com/en/ds/MAX3420E.pdf
> + * o MAX342{0,1}E Programming Guides
> + * https://pdfserv.maximintegrated.com/en/an/AN3598.pdf
> + * https://pdfserv.maximintegrated.com/en/an/AN3785.pdf
> + *
> + * This file is licenced under the GPL v2.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_irq.h>
> +#include <linux/prefetch.h>
> +#include <linux/usb/ch9.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/spi/spi.h>
> +#include <linux/gpio/consumer.h>
> +
> +#define MAX3420_MAX_EPS 4
> +#define EP_MAX_PACKET 64 /* Same for all Endpoints */
> +#define EPNAME_SIZE 16 /* Buffer size for endpoint name */
> +
> +#define ACKSTAT BIT(0)

Let's prepend everything with MAX3420_.

> +#define MAX3420_SPI_DIR_RD 0 /* read register from MAX3420 */
> +#define MAX3420_SPI_DIR_WR 1 /* write register to MAX3420 */
> +
> +/* SPI commands: */
> +#define MAX3420_SPI_DIR_SHIFT 1
> +#define MAX3420_SPI_REG_SHIFT 3
> +
> +#define MAX3420_REG_EP0FIFO 0
> +#define MAX3420_REG_EP1FIFO 1
> +#define MAX3420_REG_EP2FIFO 2
> +#define MAX3420_REG_EP3FIFO 3
> +#define MAX3420_REG_SUDFIFO 4
> +#define MAX3420_REG_EP0BC 5
> +#define MAX3420_REG_EP1BC 6
> +#define MAX3420_REG_EP2BC 7
> +#define MAX3420_REG_EP3BC 8
> +
> +#define MAX3420_REG_EPSTALLS 9
> + #define bACKSTAT BIT(6)

let's avoid CaMeLcAsE :-)

> +#define field(val, bit) ((val) << (bit))

The kernel has a bunch of helpers for this. Look at BIT() and GENMASK()
for example.

> +struct max3420_req {
> + struct usb_request usb_req;
> + struct list_head queue;
> + struct max3420_ep *ep;
> +};
> +
> +struct max3420_ep {
> + struct max3420_udc *udc;
> + struct list_head queue;
> + char name[EPNAME_SIZE];
> + unsigned int maxpacket;
> + struct usb_ep ep_usb;

considering you'll run container_of() on this ep_usb field, it's wise to
put it as the first field in the struct. That way, compiler can optimize
container_of() into a simple type cast.

> +struct max3420_udc {
> + struct max3420_ep ep[MAX3420_MAX_EPS];
> + struct usb_gadget_driver *driver;
> + struct task_struct *thread_task;
> + int remote_wkp, is_selfpowered;
> + bool vbus_active, softconnect;
> + struct usb_ctrlrequest setup;
> + struct mutex spi_bus_mutex;
> + struct max3420_req ep0req;
> + struct usb_gadget gadget;

likewise with gadget field.

> + struct spi_device *spi;
> + struct device *dev;
> + spinlock_t lock;
> + bool suspended;
> + u8 ep0buf[64];
> + u32 todo;
> +};
> +
> +#define to_max3420_req(r) container_of((r), struct max3420_req, usb_req)
> +#define to_max3420_ep(e) container_of((e), struct max3420_ep, ep_usb)
> +#define to_udc(g) container_of((g), struct max3420_udc, gadget)
> +
> +#define DRIVER_DESC "MAX3420 USB Device-Mode Driver"
> +static const char driver_name[] = "max3420-udc";
> +
> +/* Control endpoint configuration.*/
> +static const struct usb_endpoint_descriptor ep0_desc = {
> + .bEndpointAddress = USB_DIR_OUT,
> + .bmAttributes = USB_ENDPOINT_XFER_CONTROL,
> + .wMaxPacketSize = cpu_to_le16(EP_MAX_PACKET),
> +};
> +
> +static void spi_ack_ctrl(struct max3420_udc *udc)
> +{
> + struct spi_device *spi = udc->spi;
> + struct spi_transfer transfer;
> + struct spi_message msg;
> + u8 txdata[1];
> +
> + memset(&transfer, 0, sizeof(transfer));
> +
> + spi_message_init(&msg);
> +
> + txdata[0] = ACKSTAT;
> + transfer.tx_buf = txdata;
> + transfer.len = 1;
> +
> + spi_message_add_tail(&transfer, &msg);
> + spi_sync(spi, &msg);

Not checking return code?

> +}
> +
> +static u8 spi_rd8_ack(struct max3420_udc *udc, u8 reg, int actstat)
> +{
> + struct spi_device *spi = udc->spi;
> + struct spi_transfer transfer;
> + struct spi_message msg;
> + u8 txdata[2], rxdata[2];
> +
> + memset(&transfer, 0, sizeof(transfer));
> +
> + spi_message_init(&msg);
> +
> + txdata[0] = field(reg, MAX3420_SPI_REG_SHIFT) |
> + field(MAX3420_SPI_DIR_RD, MAX3420_SPI_DIR_SHIFT) |
> + (actstat ? ACKSTAT : 0);
> +
> + transfer.tx_buf = txdata;
> + transfer.rx_buf = rxdata;
> + transfer.len = 2;
> +
> + spi_message_add_tail(&transfer, &msg);
> + spi_sync(spi, &msg);

Not checking return code?

> + return rxdata[1];
> +}
> +
> +static u8 spi_rd8(struct max3420_udc *udc, u8 reg)
> +{
> + return spi_rd8_ack(udc, reg, 0);
> +}
> +
> +static void spi_wr8_ack(struct max3420_udc *udc, u8 reg, u8 val, int actstat)
> +{
> + struct spi_device *spi = udc->spi;
> + struct spi_transfer transfer;
> + struct spi_message msg;
> + u8 txdata[2];
> +
> + memset(&transfer, 0, sizeof(transfer));
> +
> + spi_message_init(&msg);
> +
> + txdata[0] = field(reg, MAX3420_SPI_REG_SHIFT) |
> + field(MAX3420_SPI_DIR_WR, MAX3420_SPI_DIR_SHIFT) |
> + (actstat ? ACKSTAT : 0);
> + txdata[1] = val;
> +
> + transfer.tx_buf = txdata;
> + transfer.len = 2;
> +
> + spi_message_add_tail(&transfer, &msg);
> + spi_sync(spi, &msg);

Not checking return code?

> +}
> +
> +static void spi_wr8(struct max3420_udc *udc, u8 reg, u8 val)
> +{
> + spi_wr8_ack(udc, reg, val, 0);
> +}
> +
> +static void spi_rd_buf(struct max3420_udc *udc, u8 reg, void *buf, u8 len)
> +{
> + struct spi_device *spi = udc->spi;
> + struct spi_transfer transfer;
> + struct spi_message msg;
> + u8 local_buf[EP_MAX_PACKET + 1] = {};
> +
> + memset(&transfer, 0, sizeof(transfer));
> +
> + spi_message_init(&msg);
> +
> + local_buf[0] = (field(reg, MAX3420_SPI_REG_SHIFT) |
> + field(MAX3420_SPI_DIR_RD, MAX3420_SPI_DIR_SHIFT));
> +
> + transfer.tx_buf = &local_buf[0];
> + transfer.rx_buf = &local_buf[0];
> + transfer.len = len + 1;
> +
> + spi_message_add_tail(&transfer, &msg);
> + spi_sync(spi, &msg);

Not checking return code?

> + memcpy(buf, &local_buf[1], len);
> +}
> +
> +static void spi_wr_buf(struct max3420_udc *udc, u8 reg, void *buf, u8 len)
> +{
> + struct spi_device *spi = udc->spi;
> + struct spi_transfer transfer;
> + struct spi_message msg;
> + u8 local_buf[EP_MAX_PACKET + 1] = {};
> +
> + memset(&transfer, 0, sizeof(transfer));
> +
> + spi_message_init(&msg);
> +
> + local_buf[0] = (field(reg, MAX3420_SPI_REG_SHIFT) |
> + field(MAX3420_SPI_DIR_WR, MAX3420_SPI_DIR_SHIFT));
> + memcpy(&local_buf[1], buf, len);
> +
> + transfer.tx_buf = local_buf;
> + transfer.len = len + 1;
> +
> + spi_message_add_tail(&transfer, &msg);
> + spi_sync(spi, &msg);

Not checking return code?

> +static int spi_max3420_enable(struct max3420_ep *ep)
> +{
> + struct max3420_udc *udc = ep->udc;
> + unsigned long flags;
> + u8 epdis, epien;
> + int todo;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> + todo = ep->todo & ENABLE_EP;
> + ep->todo &= ~ENABLE_EP;
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + if (!todo || ep->id == 0)
> + return 0;
> +
> + epien = spi_rd8(udc, MAX3420_REG_EPIEN);
> + epdis = spi_rd8(udc, MAX3420_REG_CLRTOGS);
> +
> + if (todo == ENABLE) {
> + epdis &= ~BIT(ep->id + 4);
> + epien |= BIT(ep->id + 1);
> + } else {
> + epdis |= BIT(ep->id + 4);
> + epien &= ~BIT(ep->id + 1);
> + }
> +
> + spi_wr8(udc, MAX3420_REG_CLRTOGS, epdis);
> + spi_wr8(udc, MAX3420_REG_EPIEN, epien);
> +
> + return 1;

Usually we return 0 on success and a negative errno on failure. What do
you mean here by return 1?

> +static int spi_max3420_stall(struct max3420_ep *ep)
> +{
> + struct max3420_udc *udc = ep->udc;
> + unsigned long flags;
> + u8 epstalls;
> + int todo;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> + todo = ep->todo & STALL_EP;
> + ep->todo &= ~STALL_EP;
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + if (!todo || ep->id == 0)
> + return 0;
> +
> + epstalls = spi_rd8(udc, MAX3420_REG_EPSTALLS);
> + if (todo == STALL) {
> + ep->halted = 1;
> + epstalls |= BIT(ep->id + 1);
> + } else {
> + u8 clrtogs;
> +
> + ep->halted = 0;
> + epstalls &= ~BIT(ep->id + 1);
> + clrtogs = spi_rd8(udc, MAX3420_REG_CLRTOGS);
> + clrtogs |= BIT(ep->id + 1);
> + spi_wr8(udc, MAX3420_REG_CLRTOGS, clrtogs);
> + }
> + spi_wr8(udc, MAX3420_REG_EPSTALLS, epstalls | bACKSTAT);
> +
> + return 1;

and here?

> +}
> +
> +static int spi_max3420_rwkup(struct max3420_udc *udc)
> +{
> + unsigned long flags;
> + int wake_remote;
> + u8 usbctl;
> +
> + spin_lock_irqsave(&udc->lock, flags);
> + wake_remote = udc->todo & REMOTE_WAKEUP;
> + udc->todo &= ~REMOTE_WAKEUP;
> + spin_unlock_irqrestore(&udc->lock, flags);
> +
> + if (!wake_remote || !udc->suspended)
> + return 0;
> +
> + /* Set Remote-WkUp Signal*/
> + usbctl = spi_rd8(udc, MAX3420_REG_USBCTL);
> + usbctl |= bSIGRWU;
> + spi_wr8(udc, MAX3420_REG_USBCTL, usbctl);
> +
> + msleep_interruptible(5);
> +
> + /* Clear Remote-WkUp Signal*/
> + usbctl = spi_rd8(udc, MAX3420_REG_USBCTL);
> + usbctl &= ~bSIGRWU;
> + spi_wr8(udc, MAX3420_REG_USBCTL, usbctl);
> +
> + udc->suspended = false;
> +
> + return 1;

here?

> +}
> +
> +static void max3420_nuke(struct max3420_ep *ep, int status);
> +static void __max3420_stop(struct max3420_udc *udc)
> +{
> + u8 val;
> + int i;
> +
> + /* clear all pending requests */
> + for (i = 1; i < MAX3420_MAX_EPS; i++)
> + max3420_nuke(&udc->ep[i], -ECONNRESET);
> +
> + /* Disable IRQ to CPU */
> + spi_wr8(udc, MAX3420_REG_CPUCTL, 0);
> +
> + val = spi_rd8(udc, MAX3420_REG_USBCTL);
> + val |= bPWRDOWN;
> + if (udc->is_selfpowered)
> + val &= ~bHOSCSTEN;
> + else
> + val |= bHOSCSTEN;
> + spi_wr8(udc, MAX3420_REG_USBCTL, val);
> +}
> +
> +static void __max3420_start(struct max3420_udc *udc)
> +{
> + u8 val;
> +
> + /* Need this delay if bus-powered */
> + msleep_interruptible(250);

should you check if you're bus powered?

> + /* configure SPI */
> + spi_wr8(udc, MAX3420_REG_PINCTL, bFDUPSPI);
> +
> + /* Chip Reset */
> + spi_wr8(udc, MAX3420_REG_USBCTL, bCHIPRES);
> + msleep_interruptible(5);
> + spi_wr8(udc, MAX3420_REG_USBCTL, 0);
> +
> + /* Poll for OSC to stabilize */
> + while (1) {
> + val = spi_rd8(udc, MAX3420_REG_USBIRQ);
> + if (val & bOSCOKIRQ)
> + break;
> + cond_resched();
> + }

readl_poll_timeout(), maybe?

> + /* Enable PULL-UP only when Vbus detected */
> + val = spi_rd8(udc, MAX3420_REG_USBCTL);
> + val |= bVBGATE | bCONNECT;
> + spi_wr8(udc, MAX3420_REG_USBCTL, val);
> +
> + val = bURESDNIRQ | bURESIRQ;
> + if (udc->is_selfpowered)
> + val |= bNOVBUSIRQ;
> + spi_wr8(udc, MAX3420_REG_USBIEN, val);
> +
> + /* Enable only EP0 interrupts */
> + val = bIN0BAVIRQ | bOUT0DAVIRQ | bSUDAVIRQ;
> + spi_wr8(udc, MAX3420_REG_EPIEN, val);
> +
> + /* Enable IRQ to CPU */
> + spi_wr8(udc, MAX3420_REG_CPUCTL, bIE);
> +}
> +
> +static int max3420_start(struct max3420_udc *udc)
> +{
> + unsigned long flags;
> + int todo;
> +
> + spin_lock_irqsave(&udc->lock, flags);
> + todo = udc->todo & UDC_START;
> + udc->todo &= ~UDC_START;
> + spin_unlock_irqrestore(&udc->lock, flags);
> +
> + if (!todo)
> + return 0;
> +
> + if (udc->vbus_active && udc->softconnect)
> + __max3420_start(udc);
> + else
> + __max3420_stop(udc);
> +
> + return 1;
> +}
> +
> +static irqreturn_t max3420_vbus_handler(int irq, void *dev_id)
> +{
> + struct max3420_udc *udc = dev_id;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&udc->lock, flags);
> + /* its a vbus change interrupt */
> + udc->vbus_active = !udc->vbus_active;
> + udc->todo |= UDC_START;
> + usb_udc_vbus_handler(&udc->gadget, udc->vbus_active);
> + usb_gadget_set_state(&udc->gadget, udc->vbus_active
> + ? USB_STATE_POWERED : USB_STATE_NOTATTACHED);
> + spin_unlock_irqrestore(&udc->lock, flags);
> +
> + if (udc->thread_task &&
> + udc->thread_task->state != TASK_RUNNING)
> + wake_up_process(udc->thread_task);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t max3420_irq_handler(int irq, void *dev_id)
> +{
> + struct max3420_udc *udc = dev_id;
> + struct spi_device *spi = udc->spi;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&udc->lock, flags);
> + if ((udc->todo & ENABLE_IRQ) == 0) {
> + disable_irq_nosync(spi->irq);
> + udc->todo |= ENABLE_IRQ;
> + }
> + spin_unlock_irqrestore(&udc->lock, flags);
> +
> + if (udc->thread_task &&
> + udc->thread_task->state != TASK_RUNNING)
> + wake_up_process(udc->thread_task);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void max3420_getstatus(struct max3420_udc *udc)
> +{
> + struct max3420_ep *ep;
> + u16 status = 0;
> +
> + switch (udc->setup.bRequestType & USB_RECIP_MASK) {
> + case USB_RECIP_DEVICE:
> + /* Get device status */
> + status = udc->gadget.is_selfpowered << USB_DEVICE_SELF_POWERED;
> + status |= (udc->remote_wkp << USB_DEVICE_REMOTE_WAKEUP);
> + break;
> + case USB_RECIP_INTERFACE:
> + if (udc->driver->setup(&udc->gadget, &udc->setup) < 0)
> + goto stall;
> + break;
> + case USB_RECIP_ENDPOINT:
> + ep = &udc->ep[udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK];
> + if (udc->setup.wIndex & USB_DIR_IN) {
> + if (!ep->ep_usb.caps.dir_in)
> + goto stall;
> + } else {
> + if (!ep->ep_usb.caps.dir_out)
> + goto stall;
> + }
> + if (ep->halted)
> + status = 1 << USB_ENDPOINT_HALT;
> + break;
> + default:
> + goto stall;
> + }
> +
> + status = cpu_to_le16(status);
> + spi_wr_buf(udc, MAX3420_REG_EP0FIFO, &status, 2);
> + spi_wr8_ack(udc, MAX3420_REG_EP0BC, 2, 1);
> + return;
> +stall:
> + dev_err(udc->dev, "Can't respond to getstatus request\n");
> + spi_wr8(udc, MAX3420_REG_EPSTALLS, bSTLEP0IN | bSTLEP0OUT | bSTLSTAT);
> +}
> +
> +static void max3420_set_clear_feature(struct max3420_udc *udc)
> +{
> + struct max3420_ep *ep;
> + int set = udc->setup.bRequest == USB_REQ_SET_FEATURE;
> + unsigned long flags;
> + int id;
> +
> + switch (udc->setup.bRequestType) {
> + case USB_RECIP_DEVICE:
> + if (udc->setup.wValue != USB_DEVICE_REMOTE_WAKEUP)
> + break;
> +
> + if (udc->setup.bRequest == USB_REQ_SET_FEATURE)
> + udc->remote_wkp = 1;
> + else
> + udc->remote_wkp = 0;
> +
> + return spi_ack_ctrl(udc);
> +
> + case USB_RECIP_ENDPOINT:
> + if (udc->setup.wValue != USB_ENDPOINT_HALT)
> + break;
> +
> + id = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
> + ep = &udc->ep[id];
> +
> + spin_lock_irqsave(&ep->lock, flags);
> + ep->todo &= ~STALL_EP;
> + if (set)
> + ep->todo |= STALL;
> + else
> + ep->todo |= UNSTALL;
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + spi_max3420_stall(ep);
> + return;
> + default:
> + break;
> + }
> +
> + dev_err(udc->dev, "Can't respond to SET/CLEAR FEATURE\n");
> + spi_wr8(udc, MAX3420_REG_EPSTALLS, bSTLEP0IN | bSTLEP0OUT | bSTLSTAT);
> +}
> +
> +static void max3420_handle_setup(struct max3420_udc *udc)
> +{
> + struct usb_ctrlrequest setup;
> + u8 addr;
> +
> + spi_rd_buf(udc, MAX3420_REG_SUDFIFO, (void *)&setup, 8);
> +
> + udc->setup = setup;
> + udc->setup.wValue = cpu_to_le16(setup.wValue);
> + udc->setup.wIndex = cpu_to_le16(setup.wIndex);
> + udc->setup.wLength = cpu_to_le16(setup.wLength);
> +
> + switch (udc->setup.bRequest) {
> + case USB_REQ_GET_STATUS:
> + /* Data+Status phase form udc */
> + if ((udc->setup.bRequestType &
> + (USB_DIR_IN | USB_TYPE_MASK)) !=
> + (USB_DIR_IN | USB_TYPE_STANDARD)) {
> + break;
> + }
> + return max3420_getstatus(udc);
> + case USB_REQ_SET_ADDRESS:
> + /* Status phase from udc */
> + if (udc->setup.bRequestType != (USB_DIR_OUT |
> + USB_TYPE_STANDARD | USB_RECIP_DEVICE)) {
> + break;
> + }
> + addr = spi_rd8_ack(udc, MAX3420_REG_FNADDR, 1);
> + dev_dbg(udc->dev, "Assigned Address=%d\n", udc->setup.wValue);
> + return;
> + case USB_REQ_CLEAR_FEATURE:
> + case USB_REQ_SET_FEATURE:
> + /* Requests with no data phase, status phase from udc */
> + if ((udc->setup.bRequestType & USB_TYPE_MASK)
> + != USB_TYPE_STANDARD)
> + break;
> + return max3420_set_clear_feature(udc);
> + default:
> + break;
> + }
> +
> + if (udc->driver->setup(&udc->gadget, &setup) < 0) {
> + /* Stall EP0 */
> + spi_wr8(udc, MAX3420_REG_EPSTALLS,
> + bSTLEP0IN | bSTLEP0OUT | bSTLSTAT);
> + }
> +}
> +
> +static void max3420_req_done(struct max3420_req *req, int status)
> +{
> + struct max3420_ep *ep = req->ep;
> + struct max3420_udc *udc = ep->udc;
> +
> + if (req->usb_req.status == -EINPROGRESS)
> + req->usb_req.status = status;
> + else
> + status = req->usb_req.status;
> +
> + if (status && status != -ESHUTDOWN)
> + dev_err(udc->dev, "%s done %p, status %d\n",
> + ep->ep_usb.name, req, status);
> +
> + if (req->usb_req.complete)
> + req->usb_req.complete(&ep->ep_usb, &req->usb_req);
> +}
> +
> +static int do_data(struct max3420_udc *udc, int ep_id, int in)

add a max3420_ prefix like all other functions

> +{
> + struct max3420_ep *ep = &udc->ep[ep_id];
> + struct max3420_req *req;
> + int done, length, psz;
> + void *buf;
> +
> + if (list_empty(&ep->queue))
> + return 0;
> +
> + req = list_first_entry(&ep->queue, struct max3420_req, queue);
> + buf = req->usb_req.buf + req->usb_req.actual;
> +
> + psz = ep->ep_usb.maxpacket;
> + length = req->usb_req.length - req->usb_req.actual;
> + length = min(length, psz);
> +
> + if (length == 0) {
> + done = 1;
> + goto xfer_done;
> + }
> +
> + done = 0;
> + if (in) {
> + prefetch(buf);
> + spi_wr_buf(udc, MAX3420_REG_EP0FIFO + ep_id, buf, length);
> + spi_wr8(udc, MAX3420_REG_EP0BC + ep_id, length);
> + if (length < psz)
> + done = 1;
> + } else {
> + psz = spi_rd8(udc, MAX3420_REG_EP0BC + ep_id);
> + length = min(length, psz);
> + prefetchw(buf);
> + spi_rd_buf(udc, MAX3420_REG_EP0FIFO + ep_id, buf, length);
> + if (length < ep->ep_usb.maxpacket)
> + done = 1;
> + }
> +
> + req->usb_req.actual += length;
> +
> + if (req->usb_req.actual == req->usb_req.length)
> + done = 1;
> +
> +xfer_done:
> + if (done) {
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> + list_del_init(&req->queue);
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + if (ep_id == 0)
> + spi_ack_ctrl(udc);
> +
> + max3420_req_done(req, 0);
> + }
> +
> + return 1;
> +}
> +
> +static int max3420_handle_irqs(struct max3420_udc *udc)
> +{
> + u8 epien, epirq, usbirq, usbien, reg[4];
> + int ret = 0;
> +
> + spi_rd_buf(udc, MAX3420_REG_EPIRQ, reg, 4);
> + epirq = reg[0];
> + epien = reg[1];
> + usbirq = reg[2];
> + usbien = reg[3];
> +
> + usbirq &= usbien;
> + epirq &= epien;
> +
> + if (epirq & bSUDAVIRQ) {
> + spi_wr8(udc, MAX3420_REG_EPIRQ, bSUDAVIRQ);
> + max3420_handle_setup(udc);
> + return 1;
> + }
> +
> + if (usbirq & bVBUSIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bVBUSIRQ);
> + dev_dbg(udc->dev, "Cable plugged in\n");
> + return 1;
> + }
> +
> + if (usbirq & bNOVBUSIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bNOVBUSIRQ);
> + dev_dbg(udc->dev, "Cable pulled out\n");
> + return 1;
> + }
> +
> + if (usbirq & bURESIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bURESIRQ);
> + dev_dbg(udc->dev, "USB Reset - Start\n");
> + return 1;
> + }
> +
> + if (usbirq & bURESDNIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bURESDNIRQ);
> + dev_dbg(udc->dev, "USB Reset - END\n");
> + spi_wr8(udc, MAX3420_REG_USBIEN, bURESDNIRQ | bURESIRQ);
> + spi_wr8(udc, MAX3420_REG_EPIEN, bSUDAVIRQ | bIN0BAVIRQ
> + | bOUT0DAVIRQ);
> + return 1;
> + }
> +
> + if (usbirq & bSUSPIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bSUSPIRQ);
> + dev_dbg(udc->dev, "USB Suspend - Enter\n");
> + udc->suspended = true;
> + return 1;
> + }
> +
> + if (usbirq & bBUSACTIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bBUSACTIRQ);
> + dev_dbg(udc->dev, "USB Suspend - Exit\n");
> + udc->suspended = false;
> + return 1;
> + }
> +
> + if (usbirq & bRWUDNIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bRWUDNIRQ);
> + dev_dbg(udc->dev, "Asked Host to wakeup\n");
> + return 1;
> + }
> +
> + if (usbirq & bOSCOKIRQ) {
> + spi_wr8(udc, MAX3420_REG_USBIRQ, bOSCOKIRQ);
> + dev_dbg(udc->dev, "Osc stabilized, start work\n");
> + return 1;
> + }
> +
> + if (epirq & bOUT0DAVIRQ && do_data(udc, 0, 0)) {
> + spi_wr8_ack(udc, MAX3420_REG_EPIRQ, bOUT0DAVIRQ, 1);
> + ret = 1;
> + }
> +
> + if (epirq & bIN0BAVIRQ && do_data(udc, 0, 1))
> + ret = 1;
> +
> + if (epirq & bOUT1DAVIRQ && do_data(udc, 1, 0)) {
> + spi_wr8_ack(udc, MAX3420_REG_EPIRQ, bOUT1DAVIRQ, 1);
> + ret = 1;
> + }
> +
> + if (epirq & bIN2BAVIRQ && do_data(udc, 2, 1))
> + ret = 1;
> +
> + if (epirq & bIN3BAVIRQ && do_data(udc, 3, 1))
> + ret = 1;
> +
> + return ret;
> +}
> +
> +static int max3420_thread(void *dev_id)

Why do you need this thread? Sure you can't live without it?

> +{
> + struct max3420_udc *udc = dev_id;
> + struct spi_device *spi = udc->spi;
> + int i, loop_again = 1;
> + unsigned long flags;
> +
> + while (!kthread_should_stop()) {
> + if (!loop_again) {
> + ktime_t kt = ns_to_ktime(1000 * 1000 * 250); /* 250ms */
> +
> + set_current_state(TASK_INTERRUPTIBLE);
> +
> + spin_lock_irqsave(&udc->lock, flags);
> + if (udc->todo & ENABLE_IRQ) {
> + enable_irq(spi->irq);
> + udc->todo &= ~ENABLE_IRQ;
> + }
> + spin_unlock_irqrestore(&udc->lock, flags);
> +
> + schedule_hrtimeout(&kt, HRTIMER_MODE_REL);
> + }
> + loop_again = 0;
> +
> + mutex_lock(&udc->spi_bus_mutex);
> +
> + /* If bus-vbus_active and disconnected */
> + if (!udc->vbus_active || !udc->softconnect)
> + goto loop;
> +
> + if (max3420_start(udc)) {
> + loop_again = 1;
> + goto loop;
> + }
> +
> + if (max3420_handle_irqs(udc)) {
> + loop_again = 1;
> + goto loop;
> + }
> +
> + if (spi_max3420_rwkup(udc)) {
> + loop_again = 1;
> + goto loop;
> + }
> +
> + do_data(udc, 0, 1); /* get done with the EP0 ZLP */
> +
> + for (i = 1; i < MAX3420_MAX_EPS; i++) {
> + struct max3420_ep *ep = &udc->ep[i];
> +
> + if (spi_max3420_enable(ep))
> + loop_again = 1;
> + if (spi_max3420_stall(ep))
> + loop_again = 1;
> + }
> +loop:
> + mutex_unlock(&udc->spi_bus_mutex);
> + }
> +
> + set_current_state(TASK_RUNNING);
> + dev_info(udc->dev, "SPI thread exiting");
> + return 0;
> +}
> +
> +static int max3420_ep_set_halt(struct usb_ep *_ep, int stall)
> +{
> + struct max3420_ep *ep = to_max3420_ep(_ep);
> + struct max3420_udc *udc = ep->udc;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> +
> + ep->todo &= ~STALL_EP;
> + if (stall)
> + ep->todo |= STALL;
> + else
> + ep->todo |= UNSTALL;
> +
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + wake_up_process(udc->thread_task);
> +
> + dev_dbg(udc->dev, "%sStall %s\n", stall ? "" : "Un", ep->name);
> + return 0;
> +}
> +
> +static int __max3420_ep_enable(struct max3420_ep *ep,
> + const struct usb_endpoint_descriptor *desc)
> +{
> + unsigned int maxp = usb_endpoint_maxp(desc);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> + ep->ep_usb.desc = desc;
> + ep->ep_usb.maxpacket = maxp;
> +
> + ep->todo &= ~ENABLE_EP;
> + ep->todo |= ENABLE;
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + return 0;
> +}
> +
> +static int max3420_ep_enable(struct usb_ep *_ep,
> + const struct usb_endpoint_descriptor *desc)
> +{
> + struct max3420_ep *ep = to_max3420_ep(_ep);
> + struct max3420_udc *udc = ep->udc;
> +
> + __max3420_ep_enable(ep, desc);
> +
> + wake_up_process(udc->thread_task);
> +
> + return 0;
> +}
> +
> +static void max3420_nuke(struct max3420_ep *ep, int status)
> +{
> + struct max3420_req *req, *r;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> +
> + list_for_each_entry_safe(req, r, &ep->queue, queue) {
> +
> + list_del_init(&req->queue);
> +
> + spin_unlock_irqrestore(&ep->lock, flags);
> + max3420_req_done(req, status);
> + spin_lock_irqsave(&ep->lock, flags);
> + }
> +
> + spin_unlock_irqrestore(&ep->lock, flags);
> +}
> +
> +static void __max3420_ep_disable(struct max3420_ep *ep)
> +{
> + struct max3420_udc *udc = ep->udc;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ep->lock, flags);
> +
> + ep->ep_usb.desc = NULL;
> +
> + ep->todo &= ~ENABLE_EP;
> + ep->todo |= DISABLE;
> +
> + spin_unlock_irqrestore(&ep->lock, flags);
> +
> + dev_dbg(udc->dev, "Disabled %s\n", ep->name);
> +}
> +
> +static int max3420_ep_disable(struct usb_ep *_ep)
> +{
> + struct max3420_ep *ep = to_max3420_ep(_ep);
> + struct max3420_udc *udc = ep->udc;
> +
> + max3420_nuke(ep, -ESHUTDOWN);
> +
> + __max3420_ep_disable(ep);
> +
> + wake_up_process(udc->thread_task);
> +
> + return 0;
> +}
> +
> +static struct usb_request *max3420_alloc_request(struct usb_ep *_ep,
> + gfp_t gfp_flags)
> +{
> + struct max3420_ep *ep = to_max3420_ep(_ep);
> + struct max3420_req *req;
> +
> + req = kzalloc(sizeof(*req), gfp_flags);
> + if (!req)
> + return NULL;
> +
> + req->ep = ep;
> + INIT_LIST_HEAD(&req->queue);

unnecessary list initialization

--
balbi

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