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[pcie] Rip out kernel mode pcie drivers.
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Get rid of the concept of kernel mode pcie drivers.  Start to lay the
groundwork for re-defining the concept of "claimed" in order to allow
user mode code to hold multiple references to a PCI device, at most
one of which may have the device claimed at any point in time.

Change-Id: I7596de831f40feca6f846c5f78d5f9283a673abc
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@johngro
johngro committed Nov 1, 2016
1 parent 27bdfd9 commit 544684b
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Showing 8 changed files with 58 additions and 346 deletions.
13 changes: 6 additions & 7 deletions kernel/dev/pcie/debug.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -277,8 +277,8 @@ static void dump_pcie_hdr(const pcie_device_state_t& dev, lspci_params_t* params
if (dev.disabled)
printf(" [DISABLED]");

if (dev.driver)
printf(" [driver = \"%s\"]", pcie_driver_name(dev.driver));
if (dev.claimed)
printf(" [CLAIMED]");

printf("\n");
}
Expand Down Expand Up @@ -612,9 +612,8 @@ static int cmd_pciunplug(int argc, const cmd_args *argv)
if (!dev) {
printf("Failed to find PCI device %02x:%02x.%01x\n", bus_id, dev_id, func_id);
} else {
printf("Shutting down and unplugging PCI device %02x:%02x.%x (%s)...\n",
bus_id, dev_id, func_id, pcie_driver_name(dev->driver));
pcie_shutdown_device(dev);
printf("Unplugging PCI device %02x:%02x.%x...\n",
bus_id, dev_id, func_id);
dev->Unplug();
dev = nullptr;
printf("done\n");
Expand Down Expand Up @@ -673,7 +672,7 @@ static int cmd_pcirescan(int argc, const cmd_args *argv)
if (bus_drv == nullptr)
return ERR_BAD_STATE;

bus_drv->ScanAndStartDevices();
bus_drv->ScanDevices();

return NO_ERROR;
}
Expand All @@ -683,7 +682,7 @@ STATIC_COMMAND("lspci",
"Enumerate the devices detected in PCIe ECAM space",
&cmd_lspci)
STATIC_COMMAND("pciunplug",
"Unplug the specified PCIe device (shutting down the driver if needed)",
"Force \"unplug\" the specified PCIe device",
&cmd_pciunplug)
STATIC_COMMAND("pcireset",
"Initiate a Function Level Reset of the specified device.",
Expand Down
97 changes: 4 additions & 93 deletions kernel/dev/pcie/include/dev/pcie.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,9 +32,7 @@ struct pcie_config_t {
} __PACKED;

/* Fwd decls */
struct pcie_driver_registration;
struct pcie_legacy_irq_handler_state;

struct pcie_bridge_state_t;
struct pcie_device_state_t;

Expand All @@ -51,58 +49,6 @@ struct pcie_bar_info_t {
RegionAllocator::Region::UPtr allocation;
};

/* Function table registered by a device driver. Method requirements and device
* lifecycle are described below.
*
* + pcie_probe_fn
* Called by the bus driver during bus scanning/probing to determine which
* registered driver (if any) wishes to claim and manage a device. Drivers
* who wish to claim a device must return a non-NULL void* context pointer
* which will be made available as the driver_ctx member of the
* pcie_device_state_t structure and provided to subsequent callbacks via
* the pci_device member.
*
* + startup_hook
* Called by the bus driver in order to start a device after it has been
* claimed. All MMIO/PIO registers will be allocated, but un-mapped in at the
* time the startup hook is invoked, and the device IRQ will be masked.
* Devices should not enable their IRQ during startup. Device IRQs will be
* automatically enabled at the PCI level following a successful startup if a
* device has registered an IRQ hook.
*
* + shutdown_hook
* Called by the bus driver on a successfully started device when it is time
* to shut down. Device registers are guaranteed to be mapped when shutdown
* is called. Shutdown will not be called for devices who fail to start-up,
* so devices which encounter problems during start-up should take care to
* leave their device in a quiescent state before returning their error code
* to the bus driver. Devices may use pcie_enable_irq to mask their IRQ and
* synchronize with the bus's IRQ dispatcher at the appropriate point in their
* shutdown sequence.
*
* + release_hook
* Called on a non-started device when it is time to release any resources
* which may have been allocated during its life cycle. At a minimum, drivers
* who dynamically allocate context during pcie_probe_fn should register a
* release_hook in order to clean up their dynamically allocated resources. A
* driver's release hook will always be called if the driver attempted to
* claim a device during probe. Note that it is possible that the device was
* never started, or possibly never even claimed (due to hotplug or
* multithreaded races). Drivers should use the only as a chance to free any
* internal state associated with an attempt to claim a device.
*/
typedef struct pcie_driver_fn_table {
void* (*pcie_probe_fn) (const mxtl::RefPtr<pcie_device_state_t>& pci_device);
status_t (*pcie_startup_fn) (const mxtl::RefPtr<pcie_device_state_t>& pci_device);
void (*pcie_shutdown_fn)(const mxtl::RefPtr<pcie_device_state_t>& pci_device);
void (*pcie_release_fn) (void* ctx);
} pcie_driver_fn_table_t;

typedef struct pcie_driver_registration {
const char* name;
const pcie_driver_fn_table_t* fn_table;
} pcie_driver_registration_t;

/*
* Struct used to manage the relationship between a PCIe device/function and its
* associated driver. During a bus scan/probe operation, all drivers will have
Expand Down Expand Up @@ -138,14 +84,9 @@ struct pcie_device_state_t : public mxtl::RefCounted<pcie_device_state_t> {

/* State related to lifetime management */
mutable Mutex dev_lock;
mutable Mutex start_claim_lock;
bool plugged_in;
bool disabled;

/* State tracking for this device's driver (if this device has been claimed by a driver) */
const pcie_driver_registration_t* driver;
void* driver_ctx;
bool started;
bool claimed;

/* Info about the BARs computed and cached during the initial setup/probe,
* indexed by starting BAR register index */
Expand Down Expand Up @@ -284,15 +225,12 @@ mxtl::RefPtr<pcie_device_state_t> pcie_get_nth_device(uint32_t index);
* Attaches a driver to a PCI device. Returns ERR_ALREADY_BOUND if the device has already been
* claimed by another driver.
*/
status_t pcie_claim_and_start_device(const mxtl::RefPtr<pcie_device_state_t>& device,
const pcie_driver_registration_t* driver,
void* driver_ctx);
status_t pcie_claim_device(const mxtl::RefPtr<pcie_device_state_t>& device);

/*
* Shutdown and unclaim a device had been successfully claimed with
* pcie_claim_and_start_device()
* Unclaim a device had been successfully claimed with pcie_claim_device().
*/
void pcie_shutdown_device(const mxtl::RefPtr<pcie_device_state_t>& device);
void pcie_unclaim_device(const mxtl::RefPtr<pcie_device_state_t>& device);

/*
* Trigger a function level reset (if possible)
Expand Down Expand Up @@ -385,30 +323,3 @@ static inline status_t pcie_enable_mmio(const mxtl::RefPtr<pcie_device_state_t>&
enabled ? 0 : PCI_COMMAND_MEM_EN,
enabled ? PCI_COMMAND_MEM_EN : 0);
}

/*
* Simple inline helper which fetches a device driver's name, or substitutes
* "<unknown>" if the driver didn't supply a name, or for some mysterious
* reason, is NULL.
*/
static inline const char* pcie_driver_name(const pcie_driver_registration_t* driver) {
return (driver && driver->name) ? driver->name : "<unknown>";
}

#if WITH_DEV_PCIE
#define STATIC_PCIE_DRIVER(var_name, drv_name, drv_fn_table) \
extern const pcie_driver_registration_t __pcie_drv_reg_##var_name; \
const pcie_driver_registration_t __pcie_drv_reg_##var_name \
__ALIGNED(sizeof(void *)) __SECTION("pcie_builtin_drivers") = \
{ \
.name = drv_name, \
.fn_table = &drv_fn_table, \
};
#else // WITH_DEV_PCIE
#define STATIC_PCIE_DRIVER(var_name, drv_name, drv_fn_table)
#endif // WITH_DEV_PCIE

/**
* Temporary hack; do not use!
*/
void pcie_rescan_bus(void);
2 changes: 1 addition & 1 deletion kernel/dev/pcie/include/dev/pcie_bus_driver.h
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ class PcieBusDriver : public mxtl::RefCounted<PcieBusDriver> {

// TODO(johngro) : Make these private when we can.
void ForeachDevice(ForeachCallback cbk, void* ctx);
void ScanAndStartDevices();
void ScanDevices();
mxtl::RefPtr<SharedLegacyIrqHandler> FindLegacyIrqHandler(uint irq_id);
// TODO(johngro) : end TODO section

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