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intelspi: Add support for ddb/kdb -compatible polled mode

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Required for Apple and Microsoft -compatible HID-over-SPI drivers.

Most logic was already implemented in commit 3c08673438
"spibus: extend API: add cs_delay ivar, KEEP_CS and NO_SLEEP flags".
It dissallowed driver sleeps in the interrupt context. This commit
extends this feature to handle ddb/kdb context with following:
- Skip driver locking if SPI functions were called from kdb/ddb.
- Reinitialize controller if kdb/ddb initiated SPI transfer has
  interrupted another already running one. Does not work very
  reliable yet.

Reviewed by:	manu
Differential Revision:	https://reviews.freebsd.org/D41247
This commit is contained in:
Vladimir Kondratyev 2023-08-03 19:10:50 +03:00
parent 4151ac9f12
commit 5adcec04b5
2 changed files with 42 additions and 17 deletions
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57
sys/dev/intel/spi.c
View File

@ -30,6 +30,7 @@
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/proc.h>
@ -46,14 +47,27 @@
/**
* Macros for driver mutex locking
*/
#define INTELSPI_LOCK(_sc) mtx_lock(&(_sc)->sc_mtx)
#define INTELSPI_UNLOCK(_sc) mtx_unlock(&(_sc)->sc_mtx)
#define INTELSPI_IN_POLLING_MODE() (SCHEDULER_STOPPED() || kdb_active)
#define INTELSPI_LOCK(_sc) do { \
if(!INTELSPI_IN_POLLING_MODE()) \
mtx_lock(&(_sc)->sc_mtx); \
} while (0)
#define INTELSPI_UNLOCK(_sc) do { \
if(!INTELSPI_IN_POLLING_MODE()) \
mtx_unlock(&(_sc)->sc_mtx); \
} while (0)
#define INTELSPI_LOCK_INIT(_sc) \
mtx_init(&_sc->sc_mtx, device_get_nameunit((_sc)->sc_dev), \
"intelspi", MTX_DEF)
#define INTELSPI_LOCK_DESTROY(_sc) mtx_destroy(&(_sc)->sc_mtx)
#define INTELSPI_ASSERT_LOCKED(_sc) mtx_assert(&(_sc)->sc_mtx, MA_OWNED)
#define INTELSPI_ASSERT_UNLOCKED(_sc) mtx_assert(&(_sc)->sc_mtx, MA_NOTOWNED)
#define INTELSPI_ASSERT_LOCKED(_sc) do { \
if(!INTELSPI_IN_POLLING_MODE()) \
mtx_assert(&(_sc)->sc_mtx, MA_OWNED); \
} while (0)
#define INTELSPI_ASSERT_UNLOCKED(_sc) do { \
if(!INTELSPI_IN_POLLING_MODE()) \
mtx_assert(&(_sc)->sc_mtx, MA_NOTOWNED);\
} while (0)
#define INTELSPI_WRITE(_sc, _off, _val) \
bus_write_4((_sc)->sc_mem_res, (_off), (_val))
@ -342,17 +356,26 @@ intelspi_transfer(device_t dev, device_t child, struct spi_command *cmd)
INTELSPI_LOCK(sc);
/* If the controller is in use wait until it is available. */
while (sc->sc_flags & INTELSPI_BUSY) {
if ((cmd->flags & SPI_FLAG_NO_SLEEP) == SPI_FLAG_NO_SLEEP) {
INTELSPI_UNLOCK(sc);
return (EBUSY);
}
err = mtx_sleep(dev, &sc->sc_mtx, 0, "intelspi", 0);
if (err == EINTR) {
INTELSPI_UNLOCK(sc);
return (err);
if (!INTELSPI_IN_POLLING_MODE()) {
/* If the controller is in use wait until it is available. */
while (sc->sc_flags & INTELSPI_BUSY) {
if ((cmd->flags & SPI_FLAG_NO_SLEEP) != 0) {
INTELSPI_UNLOCK(sc);
return (EBUSY);
}
err = mtx_sleep(dev, &sc->sc_mtx, 0, "intelspi", 0);
if (err == EINTR) {
INTELSPI_UNLOCK(sc);
return (err);
}
}
} else {
/*
* Now we are in the middle of other transfer. Try to reset
* controller state to get predictable context.
*/
if ((sc->sc_flags & INTELSPI_BUSY) != 0)
intelspi_init(sc);
}
/* Now we have control over SPI controller. */
@ -411,7 +434,8 @@ intelspi_transfer(device_t dev, device_t child, struct spi_command *cmd)
DELAY(cs_delay);
/* Transfer as much as possible to FIFOs */
if ((cmd->flags & SPI_FLAG_NO_SLEEP) == SPI_FLAG_NO_SLEEP) {
if ((cmd->flags & SPI_FLAG_NO_SLEEP) != 0 ||
INTELSPI_IN_POLLING_MODE() || cold) {
/* We cannot wait with mtx_sleep if we're called from e.g. an ithread */
poll_limit = 2000;
while (!intelspi_transact(sc) && poll_limit-- > 0)
@ -449,7 +473,8 @@ intelspi_transfer(device_t dev, device_t child, struct spi_command *cmd)
/* Release the controller and wakeup the next thread waiting for it. */
sc->sc_flags = 0;
wakeup_one(dev);
if (!INTELSPI_IN_POLLING_MODE())
wakeup_one(dev);
INTELSPI_UNLOCK(sc);
/*

2
sys/dev/intel/spi.h
View File

@ -54,7 +54,7 @@ struct intelspi_softc {
struct spi_command *sc_cmd;
uint32_t sc_len;
uint32_t sc_read;
uint32_t sc_flags;
volatile uint32_t sc_flags;
uint32_t sc_written;
uint32_t sc_clock;
uint32_t sc_mode;