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Subject[PATCH 5.0 118/238] i2c: tegra: update maximum transfer size
Date
5.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sowjanya Komatineni <skomatineni@nvidia.com>

commit b03ff2a23359d0dd6f0a1516c6a9e9c4760ed230 upstream.

Tegra194 supports maximum 64K bytes per packet including 12 bytes of
packet header irrespective of PIO or DMA mode transfer.

This patch updates Tegra194 max write length to account for packet
header size for transfers.

Cc: stable@vger.kernel.org # 4.20+

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/i2c/busses/i2c-tegra.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -118,6 +118,9 @@
#define I2C_MST_FIFO_STATUS_TX_MASK 0xff0000
#define I2C_MST_FIFO_STATUS_TX_SHIFT 16

+/* Packet header size in bytes */
+#define I2C_PACKET_HEADER_SIZE 12
+
/*
* msg_end_type: The bus control which need to be send at end of transfer.
* @MSG_END_STOP: Send stop pulse at end of transfer.
@@ -836,12 +839,13 @@ static const struct i2c_algorithm tegra_
/* payload size is only 12 bit */
static const struct i2c_adapter_quirks tegra_i2c_quirks = {
.flags = I2C_AQ_NO_ZERO_LEN,
- .max_read_len = 4096,
- .max_write_len = 4096 - 12,
+ .max_read_len = SZ_4K,
+ .max_write_len = SZ_4K - I2C_PACKET_HEADER_SIZE,
};

static const struct i2c_adapter_quirks tegra194_i2c_quirks = {
.flags = I2C_AQ_NO_ZERO_LEN,
+ .max_write_len = SZ_64K - I2C_PACKET_HEADER_SIZE,
};

static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {

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