From: Alexander Sverdlin <[email protected]>

commit f3b70b6e3390bfdf18fdd7d278a72a12784fdcce upstream

Underlying I2C bus drivers not always support longer transfers and
imx-lpi2c for instance doesn't. SLB 9673 offers 427-bytes packets.

Visible symptoms are:

tpm tpm0: Error left over data
tpm tpm0: tpm_transmit: tpm_recv: error -5
tpm_tis_i2c: probe of 1-002e failed with error -5

Cc: [email protected] # v5.20+
Fixes: bbc23a07b072 ("tpm: Add tpm_tis_i2c backend for tpm_tis_core")
Tested-by: Michael Haener <[email protected]>
Signed-off-by: Alexander Sverdlin <[email protected]>
Reviewed-by: Jarkko Sakkinen <[email protected]>
Reviewed-by: Jerry Snitselaar <[email protected]>
Signed-off-by: Jarkko Sakkinen <[email protected]>
Signed-off-by: Li Wang <[email protected]>
---
 drivers/char/tpm/tpm_tis_i2c.c | 37 ++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
index fe29039ce7b0..336bea6d37be 100644
--- a/drivers/char/tpm/tpm_tis_i2c.c
+++ b/drivers/char/tpm/tpm_tis_i2c.c
@@ -189,21 +189,28 @@ static int tpm_tis_i2c_read_bytes(struct tpm_tis_data 
*data, u32 addr, u16 len,
        int ret;
 
        for (i = 0; i < TPM_RETRY; i++) {
-               /* write register */
-               msg.len = sizeof(reg);
-               msg.buf = &reg;
-               msg.flags = 0;
-               ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
-               if (ret < 0)
-                       return ret;
-
-               /* read data */
-               msg.buf = result;
-               msg.len = len;
-               msg.flags = I2C_M_RD;
-               ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
-               if (ret < 0)
-                       return ret;
+               u16 read = 0;
+
+               while (read < len) {
+                       /* write register */
+                       msg.len = sizeof(reg);
+                       msg.buf = &reg;
+                       msg.flags = 0;
+                       ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
+                       if (ret < 0)
+                               return ret;
+
+                       /* read data */
+                       msg.buf = result + read;
+                       msg.len = len - read;
+                       msg.flags = I2C_M_RD;
+                       if (msg.len > I2C_SMBUS_BLOCK_MAX)
+                               msg.len = I2C_SMBUS_BLOCK_MAX;
+                       ret = tpm_tis_i2c_retry_transfer_until_ack(data, &msg);
+                       if (ret < 0)
+                               return ret;
+                       read += msg.len;
+               }
 
                ret = tpm_tis_i2c_sanity_check_read(reg, len, result);
                if (ret == 0)
-- 
2.39.1

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