From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH] tpm: constify transmit data pointers Date: Thu, 7 Sep 2017 19:24:03 +0300 Message-ID: <20170907162403.4o3li6k74livw2bk@linux.intel.com> References: <20170907133130.2463746-1-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170907133130.2463746-1-arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Peter Huewe , Marcel Selhorst , Jason Gunthorpe , Colin Ian King , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org List-Id: tpmdd-devel@lists.sourceforge.net On Thu, Sep 07, 2017 at 03:30:45PM +0200, Arnd Bergmann wrote: > Making cmd_getticks 'const' introduced a couple of harmless warnings: > > drivers/char/tpm/tpm_tis_core.c: In function 'probe_itpm': > drivers/char/tpm/tpm_tis_core.c:469:31: error: passing argument 2 of 'tpm_tis_send_data' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers] > rc = tpm_tis_send_data(chip, cmd_getticks, len); > drivers/char/tpm/tpm_tis_core.c:477:31: error: passing argument 2 of 'tpm_tis_send_data' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers] > rc = tpm_tis_send_data(chip, cmd_getticks, len); > drivers/char/tpm/tpm_tis_core.c:255:12: note: expected 'u8 * {aka unsigned char *}' but argument is of type 'const u8 * {aka const unsigned char *}' > static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) > > This changes the related functions to all take 'const' pointers > so that gcc can see this as being correct. I had to slightly > modify the logic around tpm_tis_spi_transfer() for this to work > without introducing ugly casts. > > Fixes: 5e35bd8e06b9 ("tpm_tis: make array cmd_getticks static const to shink object code size") > Signed-off-by: Arnd Bergmann > --- > drivers/char/tpm/tpm_tis.c | 2 +- > drivers/char/tpm/tpm_tis_core.c | 4 ++-- > drivers/char/tpm/tpm_tis_core.h | 4 ++-- > drivers/char/tpm/tpm_tis_spi.c | 25 +++++++++++-------------- > 4 files changed, 16 insertions(+), 19 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c > index 7e55aa9ce680..ebd0e75a3e4d 100644 > --- a/drivers/char/tpm/tpm_tis.c > +++ b/drivers/char/tpm/tpm_tis.c > @@ -223,7 +223,7 @@ static int tpm_tcg_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len, > } > > static int tpm_tcg_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len, > - u8 *value) > + const u8 *value) > { > struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data); > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 1e957e923d21..fdde971bc810 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -252,7 +252,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) > * tpm.c can skip polling for the data to be available as the interrupt is > * waited for here > */ > -static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len) > +static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > { > struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > int rc, status, burstcnt; > @@ -343,7 +343,7 @@ static void disable_interrupts(struct tpm_chip *chip) > * tpm.c can skip polling for the data to be available as the interrupt is > * waited for here > */ > -static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len) > +static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) > { > struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); > int rc; > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index e2212f021a02..6bbac319ff3b 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -98,7 +98,7 @@ struct tpm_tis_phy_ops { > int (*read_bytes)(struct tpm_tis_data *data, u32 addr, u16 len, > u8 *result); > int (*write_bytes)(struct tpm_tis_data *data, u32 addr, u16 len, > - u8 *value); > + const u8 *value); > int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result); > int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result); > int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src); > @@ -128,7 +128,7 @@ static inline int tpm_tis_read32(struct tpm_tis_data *data, u32 addr, > } > > static inline int tpm_tis_write_bytes(struct tpm_tis_data *data, u32 addr, > - u16 len, u8 *value) > + u16 len, const u8 *value) > { > return data->phy_ops->write_bytes(data, addr, len, value); > } > diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c > index 88fe72ae967f..e49f5b9b739a 100644 > --- a/drivers/char/tpm/tpm_tis_spi.c > +++ b/drivers/char/tpm/tpm_tis_spi.c > @@ -57,7 +57,7 @@ static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *da > } > > static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > - u8 *buffer, u8 direction) > + u8 *in, const u8 *out) > { > struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data); > int ret = 0; > @@ -71,7 +71,7 @@ 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[0] = (in ? 0x80 : 0) | (transfer_len - 1); > phy->tx_buf[1] = 0xd4; > phy->tx_buf[2] = addr >> 8; > phy->tx_buf[3] = addr; > @@ -112,14 +112,8 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > spi_xfer.cs_change = 0; > spi_xfer.len = transfer_len; > spi_xfer.delay_usecs = 5; > - > - if (direction) { > - spi_xfer.tx_buf = NULL; > - spi_xfer.rx_buf = buffer; > - } else { > - spi_xfer.tx_buf = buffer; > - spi_xfer.rx_buf = NULL; > - } > + spi_xfer.tx_buf = out; > + spi_xfer.rx_buf = in; > > spi_message_init(&m); > spi_message_add_tail(&spi_xfer, &m); > @@ -128,7 +122,10 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > goto exit; > > len -= transfer_len; > - buffer += transfer_len; > + if (in) > + in += transfer_len; > + if (out) > + out += transfer_len; > } > > exit: > @@ -139,13 +136,13 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len, > static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr, > u16 len, u8 *result) > { > - return tpm_tis_spi_transfer(data, addr, len, result, 0x80); > + return tpm_tis_spi_transfer(data, addr, len, result, NULL); > } > > static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr, > - u16 len, u8 *value) > + u16 len, const u8 *value) > { > - return tpm_tis_spi_transfer(data, addr, len, value, 0); > + return tpm_tis_spi_transfer(data, addr, len, NULL, value); > } > > static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result) > -- > 2.9.0 > Thank you Arnd. Do you mind if squash this to Colin's commit and your signed-off-by to that one? /Jarkko