| Message ID | 20170704135609.5064-1-Alexander.Steffen@infineon.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jul 04, 2017 at 03:56:09PM +0200, Alexander Steffen wrote: > struct tpm_tis_spi_phy { > struct tpm_tis_data priv; > struct spi_device *spi_device; > - > - u8 tx_buf[4]; > - u8 rx_buf[4]; > + u8 *iobuf; tpm_tis_spi_phy is already devm_kzalloc'd, why embed another kalloc pointer inside it? > + phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); > + if (!phy->iobuf) > + return -ENOMEM; Just do: struct tpm_tis_spi_phy { struct tpm_tis_data priv; struct spi_device *spi_device; u64 iobuf[MAX_SPI_FRAMESIZE/8]; Jason ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
On Tue, 2017-07-04 at 15:56 +0200, Alexander Steffen wrote: > The buffers used as tx_buf/rx_buf in a SPI transfer need to be DMA-safe. > This cannot be guaranteed for the buffers passed to tpm_tis_spi_read_bytes > and tpm_tis_spi_write_bytes. Therefore, we need to use our own DMA-safe > buffer and copy the data to/from it. > > Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") > Cc: stable@vger.kernel.org > Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> The commit message does not explain much how you are sorting it out and how/why it works. /Jarkko > --- > drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c > index 88fe72a..5321245 100644 > --- a/drivers/char/tpm/tpm_tis_spi.c > +++ b/drivers/char/tpm/tpm_tis_spi.c > @@ -46,9 +46,7 @@ > struct tpm_tis_spi_phy { > struct tpm_tis_data priv; > struct spi_device *spi_device; > - > - u8 tx_buf[4]; > - u8 rx_buf[4]; > + u8 *iobuf; > }; > > static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data) > @@ -71,14 +69,14 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > while (len) { > transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE); > > - phy->tx_buf[0] = direction | (transfer_len - 1); > - phy->tx_buf[1] = 0xd4; > - phy->tx_buf[2] = addr >> 8; > - phy->tx_buf[3] = addr; > + phy->iobuf[0] = direction | (transfer_len - 1); > + phy->iobuf[1] = 0xd4; > + phy->iobuf[2] = addr >> 8; > + phy->iobuf[3] = addr; > > memset(&spi_xfer, 0, sizeof(spi_xfer)); > - spi_xfer.tx_buf = phy->tx_buf; > - spi_xfer.rx_buf = phy->rx_buf; > + spi_xfer.tx_buf = phy->iobuf; > + spi_xfer.rx_buf = phy->iobuf; > spi_xfer.len = 4; > spi_xfer.cs_change = 1; > > @@ -88,9 +86,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > if (ret < 0) > goto exit; > > - if ((phy->rx_buf[3] & 0x01) == 0) { > + if ((phy->iobuf[3] & 0x01) == 0) { > // handle SPI wait states > - phy->tx_buf[0] = 0; > + phy->iobuf[0] = 0; > > for (i = 0; i < TPM_RETRY; i++) { > spi_xfer.len = 1; > @@ -99,7 +97,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > ret = spi_sync_locked(phy->spi_device, &m); > if (ret < 0) > goto exit; > - if (phy->rx_buf[0] & 0x01) > + if (phy->iobuf[0] & 0x01) > break; > } > > @@ -115,10 +113,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > > if (direction) { > spi_xfer.tx_buf = NULL; > - spi_xfer.rx_buf = buffer; > } else { > - spi_xfer.tx_buf = buffer; > spi_xfer.rx_buf = NULL; > + memcpy(phy->iobuf, buffer, transfer_len); > } > > spi_message_init(&m); > @@ -127,6 +124,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > if (ret < 0) > goto exit; > > + if (direction) > + memcpy(buffer, phy->iobuf, transfer_len); > + > len -= transfer_len; > buffer += transfer_len; > } > @@ -194,6 +194,10 @@ static int tpm_tis_spi_probe(struct spi_device *dev) > > phy->spi_device = dev; > > + phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); > + if (!phy->iobuf) > + return -ENOMEM; > + > return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops, > NULL); > } ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> > struct tpm_tis_spi_phy { > > struct tpm_tis_data priv; > > struct spi_device *spi_device; > > - > > - u8 tx_buf[4]; > > - u8 rx_buf[4]; > > + u8 *iobuf; > > tpm_tis_spi_phy is already devm_kzalloc'd, why embed another kalloc > pointer inside it? I was mostly going by the documentation in https://www.kernel.org/doc/Documentation/DMA-API-HOWTO.txt. Allocating a new buffer ensures that it is cacheline-aligned and not shared with other data, as advised: "Even if those classes of memory could physically work with DMA, you'd need to ensure the I/O buffers were cacheline-aligned." "Also, systems with caches that aren't DMA-coherent will work better when the underlying buffers don't share cache lines with other data." Is that sufficient to justify this implementation? Then I will add some more explanations along those lines to the commit message and resubmit the patch. Alexander ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c index 88fe72a..5321245 100644 --- a/drivers/char/tpm/tpm_tis_spi.c +++ b/drivers/char/tpm/tpm_tis_spi.c @@ -46,9 +46,7 @@ struct tpm_tis_spi_phy { struct tpm_tis_data priv; struct spi_device *spi_device; - - u8 tx_buf[4]; - u8 rx_buf[4]; + u8 *iobuf; }; static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data) @@ -71,14 +69,14 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, while (len) { transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE); - phy->tx_buf[0] = direction | (transfer_len - 1); - phy->tx_buf[1] = 0xd4; - phy->tx_buf[2] = addr >> 8; - phy->tx_buf[3] = addr; + phy->iobuf[0] = direction | (transfer_len - 1); + phy->iobuf[1] = 0xd4; + phy->iobuf[2] = addr >> 8; + phy->iobuf[3] = addr; memset(&spi_xfer, 0, sizeof(spi_xfer)); - spi_xfer.tx_buf = phy->tx_buf; - spi_xfer.rx_buf = phy->rx_buf; + spi_xfer.tx_buf = phy->iobuf; + spi_xfer.rx_buf = phy->iobuf; spi_xfer.len = 4; spi_xfer.cs_change = 1; @@ -88,9 +86,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; - if ((phy->rx_buf[3] & 0x01) == 0) { + if ((phy->iobuf[3] & 0x01) == 0) { // handle SPI wait states - phy->tx_buf[0] = 0; + phy->iobuf[0] = 0; for (i = 0; i < TPM_RETRY; i++) { spi_xfer.len = 1; @@ -99,7 +97,7 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, ret = spi_sync_locked(phy->spi_device, &m); if (ret < 0) goto exit; - if (phy->rx_buf[0] & 0x01) + if (phy->iobuf[0] & 0x01) break; } @@ -115,10 +113,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (direction) { spi_xfer.tx_buf = NULL; - spi_xfer.rx_buf = buffer; } else { - spi_xfer.tx_buf = buffer; spi_xfer.rx_buf = NULL; + memcpy(phy->iobuf, buffer, transfer_len); } spi_message_init(&m); @@ -127,6 +124,9 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, if (ret < 0) goto exit; + if (direction) + memcpy(buffer, phy->iobuf, transfer_len); + len -= transfer_len; buffer += transfer_len; } @@ -194,6 +194,10 @@ static int tpm_tis_spi_probe(struct spi_device *dev) phy->spi_device = dev; + phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL); + if (!phy->iobuf) + return -ENOMEM; + return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops, NULL); }
The buffers used as tx_buf/rx_buf in a SPI transfer need to be DMA-safe. This cannot be guaranteed for the buffers passed to tpm_tis_spi_read_bytes and tpm_tis_spi_write_bytes. Therefore, we need to use our own DMA-safe buffer and copy the data to/from it. Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy") Cc: stable@vger.kernel.org Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com> --- drivers/char/tpm/tpm_tis_spi.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-)