Op 11-10-2024 om 12:41 schreef Manikanta Guntupalli:
Rework the read and write code paths in the driver to support operation
in atomic contexts.
Similar changes have been implemented in other drivers, including:
commit 3a5ee18d2a32 ("i2c: imx: implement master_xfer_atomic callback")
commit 445094c8a9fb ("i2c: exynos5: add support for atomic transfers")
commit ede2299f7101 ("i2c: tegra: Support atomic transfers")
commit fe402bd09049 ("i2c: meson: implement the master_xfer_atomic
callback")
Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@xxxxxxx>
---
drivers/i2c/busses/i2c-xiic.c | 245 +++++++++++++++++++++++++++++-----
1 file changed, 212 insertions(+), 33 deletions(-)
diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c
index 052bae4fc664..e5e9a4993bd4 100644
--- a/drivers/i2c/busses/i2c-xiic.c
+++ b/drivers/i2c/busses/i2c-xiic.c
[...]
+static void xiic_recv_atomic(struct xiic_i2c *i2c)
+{
+ while (xiic_rx_space(i2c)) {
Let's remind what xiic_rx_space is
#define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos)
+ if (xiic_getreg32(i2c, XIIC_IISR_OFFSET) & XIIC_INTR_RX_FULL_MASK) {
+ if (!i2c->rx_msg) {
This check is suspicious. If i2c->rx_msg is NULL then the while
above already dereferenced a NULL pointer.
What is going on?
[...]
+}
[...]
+static void xiic_send_rem_atomic(struct xiic_i2c *i2c)
+{
+ if (!i2c->tx_msg)
+ goto send_atomic_out;
+ while (xiic_tx_space(i2c)) {
[...]
+ }
+send_atomic_out:
+ if (i2c->nmsgs > 1) {
+ i2c->nmsgs--;
+ i2c->tx_msg++;
We can get here with i2c->tx_msg being NULL. See the first if
in the function.
+ __xiic_start_xfer(i2c);
+ } else {
+ xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
+ }
}
[...]
