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Subject[PATCH] tpm: constify transmit data pointers
Date
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 <arnd@arndb.de>
---
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
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