From: David Mosberger-Tang <davidm@xxxxxxxxxx>
kmalloc the SPI rx and tx data buffers. This appears to be the only
portable way to guarantee that the buffers are DMA-safe (e.g., in
separate DMA cache-lines). This patch makes the spi_rdX()/spi_wrX()
non-reentrant, but that's OK because calls to them are guaranteed to
be serialized by the per-HCD SPI-thread.
Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: David Mosberger <davidm@xxxxxxxxxx>
---
drivers/usb/host/max3421-hcd.c | 94 +++++++++++++++++++++++++---------------
1 file changed, 60 insertions(+), 34 deletions(-)
diff --git a/drivers/usb/host/max3421-hcd.c b/drivers/usb/host/max3421-hcd.c
index 28abda1..fa5ee8e 100644
--- a/drivers/usb/host/max3421-hcd.c
+++ b/drivers/usb/host/max3421-hcd.c
@@ -102,6 +102,10 @@ enum scheduling_pass {
SCHED_PASS_DONE
};
+struct max3421_dma_buf {
+ u8 data[2];
+};
+
struct max3421_hcd {
spinlock_t lock;
@@ -124,6 +128,12 @@ struct max3421_hcd {
u8 rev; /* chip revision */
u16 frame_number;
/*
+ * kmalloc'd buffers guaranteed to be in separate (DMA)
+ * cache-lines:
+ */
+ struct max3421_dma_buf *tx;
+ struct max3421_dma_buf *rx;
+ /*
* URB we're currently processing. Must not be reset to NULL
* unless MAX3421E chip is idle:
*/
@@ -332,51 +342,47 @@ max3421_to_hcd(struct max3421_hcd *max3421_hcd)
static u8
spi_rd8(struct usb_hcd *hcd, unsigned int reg)
{
+ struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
struct spi_device *spi = to_spi_device(hcd->self.controller);
struct spi_transfer transfer;
- u8 tx_data[1];
- /*
- * RX data must be in its own cache-line so it stays flushed
- * from the cache until the transfer is complete. Otherwise,
- * we get stale data from the cache.
- */
- u8 rx_data[SMP_CACHE_BYTES] ____cacheline_aligned;
struct spi_message msg;
memset(&transfer, 0, sizeof(transfer));
spi_message_init(&msg);
- tx_data[0] = (field(reg, MAX3421_SPI_REG_SHIFT) |
- field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
+ max3421_hcd->tx->data[0] =
+ (field(reg, MAX3421_SPI_REG_SHIFT) |
+ field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
- transfer.tx_buf = tx_data;
- transfer.rx_buf = rx_data;
+ transfer.tx_buf = max3421_hcd->tx->data;
+ transfer.rx_buf = max3421_hcd->rx->data;
transfer.len = 2;
spi_message_add_tail(&transfer, &msg);
spi_sync(spi, &msg);
- return rx_data[1];
+ return max3421_hcd->rx->data[1];
}
static void
spi_wr8(struct usb_hcd *hcd, unsigned int reg, u8 val)
{
struct spi_device *spi = to_spi_device(hcd->self.controller);
+ struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
struct spi_transfer transfer;
struct spi_message msg;
- u8 tx_data[2];
memset(&transfer, 0, sizeof(transfer));
spi_message_init(&msg);
- tx_data[0] = (field(reg, MAX3421_SPI_REG_SHIFT) |
- field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
- tx_data[1] = val;
+ max3421_hcd->tx->data[0] =
+ (field(reg, MAX3421_SPI_REG_SHIFT) |
+ field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
+ max3421_hcd->tx->data[1] = val;
- transfer.tx_buf = tx_data;
+ transfer.tx_buf = max3421_hcd->tx->data;
transfer.len = 2;
spi_message_add_tail(&transfer, &msg);
@@ -387,18 +393,18 @@ static void
spi_rd_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
{
struct spi_device *spi = to_spi_device(hcd->self.controller);
+ struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
struct spi_transfer transfer[2];
struct spi_message msg;
- u8 cmd;
memset(transfer, 0, sizeof(transfer));
spi_message_init(&msg);
- cmd = (field(reg, MAX3421_SPI_REG_SHIFT) |
- field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
-
- transfer[0].tx_buf = &cmd;
+ max3421_hcd->tx->data[0] =
+ (field(reg, MAX3421_SPI_REG_SHIFT) |
+ field(MAX3421_SPI_DIR_RD, MAX3421_SPI_DIR_SHIFT));
+ transfer[0].tx_buf = max3421_hcd->tx->data;
transfer[0].len = 1;
transfer[1].rx_buf = buf;
@@ -413,18 +419,19 @@ static void
spi_wr_buf(struct usb_hcd *hcd, unsigned int reg, void *buf, size_t len)
{
struct spi_device *spi = to_spi_device(hcd->self.controller);
+ struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd);
struct spi_transfer transfer[2];
struct spi_message msg;
- u8 cmd;
memset(transfer, 0, sizeof(transfer));
spi_message_init(&msg);
- cmd = (field(reg, MAX3421_SPI_REG_SHIFT) |
- field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
+ max3421_hcd->tx->data[0] =
+ (field(reg, MAX3421_SPI_REG_SHIFT) |
+ field(MAX3421_SPI_DIR_WR, MAX3421_SPI_DIR_SHIFT));
- transfer[0].tx_buf = &cmd;
+ transfer[0].tx_buf = max3421_hcd->tx->data;
transfer[0].len = 1;
transfer[1].tx_buf = buf;
@@ -1831,8 +1838,8 @@ static int
max3421_probe(struct spi_device *spi)
{
struct max3421_hcd *max3421_hcd;
- struct usb_hcd *hcd;
- int retval;
+ struct usb_hcd *hcd = NULL;
+ int retval = -ENOMEM;
if (spi_setup(spi) < 0) {
dev_err(&spi->dev, "Unable to setup SPI bus");
@@ -1843,7 +1850,7 @@ max3421_probe(struct spi_device *spi)
dev_name(&spi->dev));
if (!hcd) {
dev_err(&spi->dev, "failed to create HCD structure\n");
- return -ENOMEM;
+ goto error;
}
set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
max3421_hcd = hcd_to_max3421(hcd);
@@ -1851,29 +1858,48 @@ max3421_probe(struct spi_device *spi)
max3421_hcd_list = max3421_hcd;
INIT_LIST_HEAD(&max3421_hcd->ep_list);
+ max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
+ if (!max3421_hcd->tx) {
+ dev_err(&spi->dev, "failed to kmalloc tx buffer\n");
+ goto error;
+ }
+ max3421_hcd->rx = kmalloc(sizeof(*max3421_hcd->rx), GFP_KERNEL);
+ if (!max3421_hcd->rx) {
+ dev_err(&spi->dev, "failed to kmalloc rx buffer\n");
+ goto error;
+ }
+
max3421_hcd->spi_thread = kthread_run(max3421_spi_thread, hcd,
"max3421_spi_thread");
if (max3421_hcd->spi_thread == ERR_PTR(-ENOMEM)) {
dev_err(&spi->dev,
"failed to create SPI thread (out of memory)\n");
- return -ENOMEM;
+ goto error;
}
retval = usb_add_hcd(hcd, 0, 0);
if (retval) {
dev_err(&spi->dev, "failed to add HCD\n");
- usb_put_hcd(hcd);
- return retval;
+ goto error;
}
retval = request_irq(spi->irq, max3421_irq_handler,
IRQF_TRIGGER_LOW, "max3421", hcd);
if (retval < 0) {
- usb_put_hcd(hcd);
dev_err(&spi->dev, "failed to request irq %d\n", spi->irq);
- return retval;
+ goto error;
}
return 0;
+
+error:
+ if (hcd) {
+ kfree(max3421_hcd->tx);
+ kfree(max3421_hcd->rx);
+ if (max3421_hcd->spi_thread)
+ kthread_stop(max3421_hcd->spi_thread);
+ usb_put_hcd(hcd);
+ }
+ return retval;
}
static int
--
1.7.9.5
--
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