firmware: arm_scmi: Fix device node validation for mailbox transport

When mailboxes are used as a transport it is possible to setup the SCMI
transport layer, depending on the underlying channels configuration, to use
one or two mailboxes, associated, respectively, to one or two, distinct,
shared memory areas: any other combination should be treated as invalid.

Add more strict checking of SCMI mailbox transport device node descriptors.

Fixes: 5c8a47a5a9 ("firmware: arm_scmi: Make scmi core independent of the transport type")
Cc: <stable@vger.kernel.org> # 4.19
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230307162324.891866-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Cristian Marussi 2023-03-07 16:23:24 +00:00 committed by Sudeep Holla
parent b2b76e977f
commit 2ab4f4018c
1 changed files with 37 additions and 0 deletions

View File

@ -52,6 +52,39 @@ static bool mailbox_chan_available(struct device_node *of_node, int idx)
"#mbox-cells", idx, NULL);
}
static int mailbox_chan_validate(struct device *cdev)
{
int num_mb, num_sh, ret = 0;
struct device_node *np = cdev->of_node;
num_mb = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
num_sh = of_count_phandle_with_args(np, "shmem", NULL);
/* Bail out if mboxes and shmem descriptors are inconsistent */
if (num_mb <= 0 || num_sh > 2 || num_mb != num_sh) {
dev_warn(cdev, "Invalid channel descriptor for '%s'\n",
of_node_full_name(np));
return -EINVAL;
}
if (num_sh > 1) {
struct device_node *np_tx, *np_rx;
np_tx = of_parse_phandle(np, "shmem", 0);
np_rx = of_parse_phandle(np, "shmem", 1);
/* SCMI Tx and Rx shared mem areas have to be distinct */
if (!np_tx || !np_rx || np_tx == np_rx) {
dev_warn(cdev, "Invalid shmem descriptor for '%s'\n",
of_node_full_name(np));
ret = -EINVAL;
}
of_node_put(np_tx);
of_node_put(np_rx);
}
return ret;
}
static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
bool tx)
{
@ -64,6 +97,10 @@ static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
resource_size_t size;
struct resource res;
ret = mailbox_chan_validate(cdev);
if (ret)
return ret;
smbox = devm_kzalloc(dev, sizeof(*smbox), GFP_KERNEL);
if (!smbox)
return -ENOMEM;