Add a comment to explain the code under is_secure condition of
ti_sci_do_xfer. This will help avoid confusion amongst people who may in
future touch upon this code.

Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>

The ti_sci driver in U-Boot has support for secure_msg as part of it's
do_xfer function. This let's U-boot send secure messages during boot up.

The protocol to send such secure messages is described as part of the
struct ti_sci_secure_msg_hdr. As part of this, there are 2 fields for
checksum and reserved that occupy the first 4 bytes of any secure
message. This is called as the secure_hdr.

As of now, the secure_hdr needs to be 0 init-ed before sending secure
messages. However the existing code was never putting the zero-inited vars
into the secure_buf, leading to possibility of the first 4 bytes of
secure_buf being possibly garbage.

Fix this by initialising the secure_hdr itself to the secure_buf
location, thus when we make secure_hdr members 0, it automatically ensures
the first 4 bytes of secure_buf are 0.

Fixes: 32cd25128bd849 ("firmware: Add basic support for TI System Control Interface (TI SCI)")
Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>

As of now only one mailbox agent is supported by mailbox driver.
On zynqmp platform there are about 7 mailbox agents which can communicate
over same IPI channel to U-Boot. This patch series introduces new
"zynqmp_ipi_dest" driver which adds one to multi-channel mailbox
support.

Following format in device-tree is expected as per latest bindings:
zynqmp-ipi {
	compatible = "xlnx,zynqmp-ipi-mailbox";

	mbox_1: mailbox@1 {
		/* New compatible for child node */
		compatible = "xlnx,zynqmp-ipi-dest-mailbox";
		...
	};

	...

	mbox_n: mailbox@n {
		compatible = "xlnx,zynqmp-ipi-dest-mailbox";
		...
	}
};

Then mailbox client uses child mailbox node as following:

ipi-dest-1 {
	...
	mboxes = <mbox_1 0>, <mbox_1 1>;
	mbox-names = "tx", "rx";
	...
};

New "zynqmp_ipi_dest" driver is for devices with
"xlnx,zynqmp-ipi-dest-mailbox" compatible string. This driver will take care
of mailbox send recv ops and it replaces previous "zynqmp_ipi" driver.
Now "zynqmp_ipi" driver simply binds each child device with "zynqmp_ipi_dest"
driver.

However, its important to maintain backward comaptibility with previous
bindings where child node does not have compatible string. In such case, new
driver isn't probed by U-Boot during boot and system fails to boot. To
resolve this issue firmware-zynqmp.c driver probes all the IPI parent node
driver which binds each child node device with "zynqmp_ipi_dest" driver.

This makes sure corresponding child driver will be
probed when requested using mbox_get_by_name or mbox_get_by_idx
framework calls.

This way multiple mailbox agents are supported in device-tree without breaking
previous binding support.

Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
Link: https://lore.kernel.org/r/20231204215620.63334-4-tanmay.shah@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>

This change will be useful when we manually test SCMI on sandbox
by enabling/disabling a specific SCMI protocol.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

Replace instances of http://www.ti.com with https://www.ti.com

Signed-off-by: Nishanth Menon <nm@ti.com>

A power domain id on sandbox should be in the range from zero to
ARRAY_SIZE(scmi_pwdom) - 1. Correct the validity check logic.

Addresses-Coverity-ID: 467401 ("Out-of-bounds write")
Addresses-Coverity-ID: 467405 ("Out-of-bounds read")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

Unhandled error coming from xilinx_pm_request() but return
value is not read back that's why getting sparse warning
as below:
warning: variable 'ret' set but not used [-Wunused-but-set-variable].
In case of error return the "ret" value.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://lore.kernel.org/r/20231011025647.17200-1-venkatesh.abbarapu@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>

address the CID 464361 Control flow issues [1]

[1]: https://lore.kernel.org/all/20230821210927.GL3953269@bill-the-cat/

Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
Cc: Tom Rini <trini@konsulko.com>

SCMI power domain management protocol is supported on sandbox
for test purpose. Add fake agent interfaces and associated
power domain devices.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

Add power domain driver based on SCMI power domain management protocol.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>