On Fri, Jun 07, 2019 at 12:03:02PM +0530, Prabhat Chand Pandey wrote:
> This patch introduces the dbc_function structure as a first step in
> making DbC modular and capable in exposing different user interfaces using
> different "functions", which may implement the callbacks exposed here
> according to the driver's need.
>
> Only one "function" can be registered at a time.
> The generic way to enable a DbC function would be, using sys-fs:
"sysfs"
>
> Locate the directory for PCI enumerated XHCI host controller in the
> sysfs path.
> e.g.: cd /sys/bus/pci/devices/0000:00:14.0
> $ echo "enable" > dbc
You are adding a new sysfs file to the pci device? why?
> This is done AFTER the function is selected at build time. Only 1 function
> can be selected at a time.
Why?
And "dbc" is debug port, right? Or is it something else?
> Signed-off-by: Rajaram Regupathy <rajaram.regupathy@xxxxxxxxx>
> Signed-off-by: Abhilash K V <abhilash.k.v@xxxxxxxxx>
> Signed-off-by: Prabhat Chand Pandey <prabhat.chand.pandey@xxxxxxxxx>
> Acked-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/host/xhci-dbgcap.c | 159 ++++++++++++++++++++++-----------
> drivers/usb/host/xhci-dbgcap.h | 32 ++++++-
> 2 files changed, 138 insertions(+), 53 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
> index 52e32644a4b2..96adc53b0fdb 100644
> --- a/drivers/usb/host/xhci-dbgcap.c
> +++ b/drivers/usb/host/xhci-dbgcap.c
> @@ -9,11 +9,14 @@
> #include <linux/dma-mapping.h>
> #include <linux/slab.h>
> #include <linux/nls.h>
> +#include <linux/module.h>
>
> #include "xhci.h"
> #include "xhci-trace.h"
> #include "xhci-dbgcap.h"
>
> +static struct dbc_function *dbc_registered_func;
> +
> static inline void *
> dbc_dma_alloc_coherent(struct xhci_hcd *xhci, size_t size,
> dma_addr_t *dma_handle, gfp_t flags)
> @@ -35,41 +38,42 @@ dbc_dma_free_coherent(struct xhci_hcd *xhci, size_t size,
> size, cpu_addr, dma_handle);
> }
>
> -static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings)
> +static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings,
> + struct dbc_function *func)
> {
> struct usb_string_descriptor *s_desc;
> u32 string_length;
>
> /* Serial string: */
> s_desc = (struct usb_string_descriptor *)strings->serial;
> - utf8s_to_utf16s(DBC_STRING_SERIAL, strlen(DBC_STRING_SERIAL),
> + utf8s_to_utf16s(func->string.serial, strlen(func->string.serial),
> UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
> DBC_MAX_STRING_LENGTH);
>
> - s_desc->bLength = (strlen(DBC_STRING_SERIAL) + 1) * 2;
> + s_desc->bLength = (strlen(func->string.serial) + 1) * 2;
> s_desc->bDescriptorType = USB_DT_STRING;
> string_length = s_desc->bLength;
> string_length <<= 8;
>
> /* Product string: */
> s_desc = (struct usb_string_descriptor *)strings->product;
> - utf8s_to_utf16s(DBC_STRING_PRODUCT, strlen(DBC_STRING_PRODUCT),
> + utf8s_to_utf16s(func->string.product, strlen(func->string.product),
> UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
> DBC_MAX_STRING_LENGTH);
>
> - s_desc->bLength = (strlen(DBC_STRING_PRODUCT) + 1) * 2;
> + s_desc->bLength = (strlen(func->string.product) + 1) * 2;
> s_desc->bDescriptorType = USB_DT_STRING;
> string_length += s_desc->bLength;
> string_length <<= 8;
>
> /* Manufacture string: */
> s_desc = (struct usb_string_descriptor *)strings->manufacturer;
> - utf8s_to_utf16s(DBC_STRING_MANUFACTURER,
> - strlen(DBC_STRING_MANUFACTURER),
> + utf8s_to_utf16s(func->string.manufacturer,
> + strlen(func->string.manufacturer),
> UTF16_LITTLE_ENDIAN, (wchar_t *)s_desc->wData,
> DBC_MAX_STRING_LENGTH);
>
> - s_desc->bLength = (strlen(DBC_STRING_MANUFACTURER) + 1) * 2;
> + s_desc->bLength = (strlen(func->string.manufacturer) + 1) * 2;
> s_desc->bDescriptorType = USB_DT_STRING;
> string_length += s_desc->bLength;
> string_length <<= 8;
> @@ -84,7 +88,9 @@ static u32 xhci_dbc_populate_strings(struct dbc_str_descs *strings)
> return string_length;
> }
>
> -static void xhci_dbc_init_contexts(struct xhci_hcd *xhci, u32 string_length)
> +static void xhci_dbc_init_contexts(struct xhci_hcd *xhci,
> + struct dbc_function *func,
> + u32 string_length)
> {
> struct xhci_dbc *dbc;
> struct dbc_info_context *info;
> @@ -124,10 +130,10 @@ static void xhci_dbc_init_contexts(struct xhci_hcd *xhci, u32 string_length)
> /* Set DbC context and info registers: */
> xhci_write_64(xhci, dbc->ctx->dma, &dbc->regs->dccp);
>
> - dev_info = cpu_to_le32((DBC_VENDOR_ID << 16) | DBC_PROTOCOL);
> + dev_info = cpu_to_le32((func->vid << 16) | func->protocol);
> writel(dev_info, &dbc->regs->devinfo1);
>
> - dev_info = cpu_to_le32((DBC_DEVICE_REV << 16) | DBC_PRODUCT_ID);
> + dev_info = cpu_to_le32((func->device_rev << 16) | func->pid);
> writel(dev_info, &dbc->regs->devinfo2);
> }
>
> @@ -181,11 +187,13 @@ static void xhci_dbc_flush_endpoint_requests(struct dbc_ep *dep)
> xhci_dbc_flush_single_request(req);
> }
>
> -static void xhci_dbc_flush_requests(struct xhci_dbc *dbc)
> +
> +void xhci_dbc_flush_requests(struct xhci_dbc *dbc)
> {
> xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_OUT]);
> xhci_dbc_flush_endpoint_requests(&dbc->eps[BULK_IN]);
> }
> +EXPORT_SYMBOL_GPL(xhci_dbc_flush_requests);
>
> struct dbc_request *
> dbc_alloc_request(struct dbc_ep *dep, gfp_t gfp_flags)
> @@ -205,6 +213,7 @@ dbc_alloc_request(struct dbc_ep *dep, gfp_t gfp_flags)
>
> return req;
> }
> +EXPORT_SYMBOL_GPL(dbc_alloc_request);
>
> void
> dbc_free_request(struct dbc_ep *dep, struct dbc_request *req)
> @@ -213,6 +222,7 @@ dbc_free_request(struct dbc_ep *dep, struct dbc_request *req)
>
> kfree(req);
> }
> +EXPORT_SYMBOL_GPL(dbc_free_request);
>
> static void
> xhci_dbc_queue_trb(struct xhci_ring *ring, u32 field1,
> @@ -344,6 +354,7 @@ int dbc_ep_queue(struct dbc_ep *dep, struct dbc_request *req,
>
> return ret;
> }
> +EXPORT_SYMBOL_GPL(dbc_ep_queue);
>
> static inline void xhci_dbc_do_eps_init(struct xhci_hcd *xhci, bool direction)
> {
> @@ -371,7 +382,9 @@ static void xhci_dbc_eps_exit(struct xhci_hcd *xhci)
> memset(dbc->eps, 0, sizeof(struct dbc_ep) * ARRAY_SIZE(dbc->eps));
> }
>
> -static int xhci_dbc_mem_init(struct xhci_hcd *xhci, gfp_t flags)
> +static int xhci_dbc_mem_init(struct xhci_hcd *xhci,
> + struct dbc_function *func,
> + gfp_t flags)
> {
> int ret;
> dma_addr_t deq;
> @@ -418,8 +431,8 @@ static int xhci_dbc_mem_init(struct xhci_hcd *xhci, gfp_t flags)
> xhci_write_64(xhci, deq, &dbc->regs->erdp);
>
> /* Setup strings and contexts: */
> - string_length = xhci_dbc_populate_strings(dbc->string);
> - xhci_dbc_init_contexts(xhci, string_length);
> + string_length = xhci_dbc_populate_strings(dbc->string, func);
> + xhci_dbc_init_contexts(xhci, func, string_length);
>
> xhci_dbc_eps_init(xhci);
> dbc->state = DS_INITIALIZED;
> @@ -478,20 +491,9 @@ static int xhci_do_dbc_start(struct xhci_hcd *xhci)
> u32 ctrl;
> struct xhci_dbc *dbc = xhci->dbc;
>
> - if (dbc->state != DS_DISABLED)
> + if (dbc->state != DS_INITIALIZED)
> return -EINVAL;
>
> - writel(0, &dbc->regs->control);
> - ret = xhci_handshake(&dbc->regs->control,
> - DBC_CTRL_DBC_ENABLE,
> - 0, 1000);
> - if (ret)
> - return ret;
> -
> - ret = xhci_dbc_mem_init(xhci, GFP_ATOMIC);
> - if (ret)
> - return ret;
> -
> ctrl = readl(&dbc->regs->control);
> writel(ctrl | DBC_CTRL_DBC_ENABLE | DBC_CTRL_PORT_ENABLE,
> &dbc->regs->control);
> @@ -552,9 +554,13 @@ static void xhci_dbc_stop(struct xhci_hcd *xhci)
>
> cancel_delayed_work_sync(&dbc->event_work);
>
> - if (port->registered)
> - xhci_dbc_tty_unregister_device(xhci);
> -
> + if (port->registered &&
> + dbc_registered_func &&
> + dbc_registered_func->post_disconnect) {
> + ret = dbc_registered_func->post_disconnect(dbc);
> + if (ret)
> + xhci_err(xhci, "dbc post_disconnect error %d\n", ret);
> + }
> spin_lock_irqsave(&dbc->lock, flags);
> ret = xhci_do_dbc_stop(xhci);
> spin_unlock_irqrestore(&dbc->lock, flags);
> @@ -798,16 +804,12 @@ static void xhci_dbc_handle_events(struct work_struct *work)
>
> switch (evtr) {
> case EVT_GSER:
> - ret = xhci_dbc_tty_register_device(xhci);
> - if (ret) {
> - xhci_err(xhci, "failed to alloc tty device\n");
> - break;
> - }
> -
> - xhci_info(xhci, "DbC now attached to /dev/ttyDBC0\n");
> + if (dbc_registered_func->post_config)
> + dbc_registered_func->post_config(dbc);
> break;
> case EVT_DISC:
> - xhci_dbc_tty_unregister_device(xhci);
> + if (dbc_registered_func->post_disconnect)
> + ret = dbc_registered_func->post_disconnect(dbc);
> break;
> case EVT_DONE:
> break;
> @@ -912,46 +914,76 @@ static ssize_t dbc_store(struct device *dev,
> struct device_attribute *attr,
> const char *buf, size_t count)
> {
> + struct xhci_dbc *dbc;
> struct xhci_hcd *xhci;
> + int ret = 0;
>
> xhci = hcd_to_xhci(dev_get_drvdata(dev));
> + dbc = xhci->dbc;
>
> - if (!strncmp(buf, "enable", 6))
> + if (!strncmp(buf, "enable", 6) && dbc->state == DS_DISABLED) {
> + if (!dbc_registered_func)
> + return -EINVAL;
> + if (!try_module_get(dbc_registered_func->owner))
> + return -ENODEV;
> + ret = xhci_dbc_mem_init(dbc->xhci, dbc_registered_func,
> + GFP_ATOMIC);
> + if (ret)
> + goto err;
> + if (dbc_registered_func->run)
> + ret = dbc_registered_func->run(dbc);
> + if (ret) {
> + xhci_dbc_mem_cleanup(xhci);
> + dbc->state = DS_DISABLED;
> + goto err;
> + }
> xhci_dbc_start(xhci);
> - else if (!strncmp(buf, "disable", 7))
> + } else if (!strncmp(buf, "disable", 7) && dbc->state != DS_DISABLED) {
> + if (!dbc_registered_func)
> + return -EINVAL;
> xhci_dbc_stop(xhci);
> - else
> + if (dbc_registered_func->stop)
> + dbc_registered_func->stop(dbc);
> + module_put(dbc_registered_func->owner);
> + } else
> return -EINVAL;
>
> return count;
> +err:
> + module_put(dbc_registered_func->owner);
> + return ret;
> }
>
> static DEVICE_ATTR_RW(dbc);
>
> +static struct attribute *dbc_dev_attributes[] = {
> + &dev_attr_dbc.attr,
> + NULL
> +};
> +
> +static const struct attribute_group dbc_dev_attrib_grp = {
> + .attrs = dbc_dev_attributes,
> +};
> +
> +
> int xhci_dbc_init(struct xhci_hcd *xhci)
> {
> int ret;
> struct device *dev = xhci_to_hcd(xhci)->self.controller;
>
> ret = xhci_do_dbc_init(xhci);
> - if (ret)
> - goto init_err3;
> -
> - ret = xhci_dbc_tty_register_driver(xhci);
> if (ret)
> goto init_err2;
>
> - ret = device_create_file(dev, &dev_attr_dbc);
> + ret = sysfs_create_group(&dev->kobj, &dbc_dev_attrib_grp);
> if (ret)
> goto init_err1;
>
> return 0;
>
> init_err1:
> - xhci_dbc_tty_unregister_driver();
> -init_err2:
> xhci_do_dbc_exit(xhci);
> -init_err3:
> +init_err2:
> return ret;
> }
>
> @@ -963,11 +995,38 @@ void xhci_dbc_exit(struct xhci_hcd *xhci)
> return;
>
> device_remove_file(dev, &dev_attr_dbc);
> - xhci_dbc_tty_unregister_driver();
> xhci_dbc_stop(xhci);
> xhci_do_dbc_exit(xhci);
> }
>
> +static inline int is_invalid(int val)
> +{
> + return (val < 0 || val > 0xffff);
> +}
> +
> +int xhci_dbc_register_function(struct dbc_function *func)
> +{
> + if (dbc_registered_func)
> + return -EBUSY;
> +
> + if (is_invalid(func->protocol) ||
> + is_invalid(func->vid) ||
> + is_invalid(func->pid) ||
> + is_invalid(func->device_rev))
> + return -EINVAL;
> + if (!func->run || !func->stop)
> + return -EINVAL;
> + dbc_registered_func = func;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(xhci_dbc_register_function);
> +
> +void xhci_dbc_unregister_function(void)
> +{
> + dbc_registered_func = NULL;
> +}
> +EXPORT_SYMBOL_GPL(xhci_dbc_unregister_function);
> +
> #ifdef CONFIG_PM
> int xhci_dbc_suspend(struct xhci_hcd *xhci)
> {
> diff --git a/drivers/usb/host/xhci-dbgcap.h b/drivers/usb/host/xhci-dbgcap.h
> index ce0c6072bd48..b4d5622a9030 100644
> --- a/drivers/usb/host/xhci-dbgcap.h
> +++ b/drivers/usb/host/xhci-dbgcap.h
> @@ -11,6 +11,7 @@
>
> #include <linux/tty.h>
> #include <linux/kfifo.h>
> +#include <linux/kernel.h>
>
> struct dbc_regs {
> __le32 capability;
> @@ -48,9 +49,9 @@ struct dbc_info_context {
>
> #define DBC_MAX_PACKET 1024
> #define DBC_MAX_STRING_LENGTH 64
> -#define DBC_STRING_MANUFACTURER "Linux Foundation"
> -#define DBC_STRING_PRODUCT "Linux USB Debug Target"
> -#define DBC_STRING_SERIAL "0001"
> +#define DBC_STR_MANUFACTURER "Linux Foundation"
> +#define DBC_STR_PRODUCT "Linux USB Debug Target"
> +#define DBC_STR_SERIAL "0001"
> #define DBC_CONTEXT_SIZE 64
>
> /*
> @@ -75,6 +76,7 @@ struct dbc_str_descs {
> #define DBC_PRODUCT_ID 0x0010 /* device 0010 */
> #define DBC_DEVICE_REV 0x0010 /* 0.10 */
>
> +
> enum dbc_state {
> DS_DISABLED = 0,
> DS_INITIALIZED,
> @@ -108,6 +110,25 @@ struct dbc_ep {
> unsigned direction:1;
> };
>
> +struct dbc_function {
> + char func_name[32];
> + /* string descriptors */
> + struct dbc_str_descs string;
> + /* other device or interface descriptors */
> + u16 protocol;
> + u16 vid;
> + u16 pid;
> + u16 device_rev;
le16 for all of these?
> + /* callbacks */
> + int (*run)(struct xhci_dbc *dbc);
> + int (*post_config)(struct xhci_dbc *dbc);
> + int (*post_disconnect)(struct xhci_dbc *dbc);
> + int (*stop)(struct xhci_dbc *dbc);
> +
> + /* module owner */
> + struct module *owner;
> +};
Why would a function have a module owner?
What exactly is a "function"? is it a driver? If so, why not make it a
real driver, have a real bus, and bind drivers to the devices on the
bus?
thanks,
greg k-h
