Re: [PATCH v5 3/4] firmware: psci: Read and use vendor reset types

On Fri, Aug 09, 2024 at 03:30:38PM +0200, Lorenzo Pieralisi wrote:

On Wed, Aug 07, 2024 at 11:10:50AM -0700, Elliot Berman wrote:

[...]

quoted

quoted

quoted

+static void psci_vendor_sys_reset2(unsigned long action, void *data)

'action' is unused and therefore it is not really needed.

quoted

+{
+	const char *cmd = data;
+	unsigned long ret;
+	size_t i;
+
+	for (i = 0; i < num_psci_reset_params; i++) {
+		if (!strcmp(psci_reset_params[i].mode, cmd)) {
+			ret = invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2),
+					     psci_reset_params[i].reset_type,
+					     psci_reset_params[i].cookie, 0);
+			pr_err("failed to perform reset \"%s\": %ld\n",
+				cmd, (long)ret);
+		}
+	}
+}
+
 static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
 			  void *data)
 {
+	if (data && num_psci_reset_params)

So, reboot_mode here is basically ignored; if there is a vendor defined
reset, we fire it off.

I think Mark mentioned his concerns earlier related to REBOOT_* mode and
reset type (granted, the context was different):

https://lore.kernel.org/all/20200320120105.GA36658@C02TD0UTHF1T.local/ (local)

I would like to understand if this is the right thing to do before
accepting this patchset.

I don't have any concerns to move this part below checking reboot_mode.
Or, I could add reboot_mode == REBOOT_COLD check.

The question is how can we map vendor specific reboot magic to Linux
reboot modes sensibly in generic PSCI code - that's by definition
vendor specific.

I don't think it's a reasonable thing to do. "reboot bootloader" or
"reboot edl" don't make sense to the Linux reboot modes.

I believe the Linux reboot modes enum is oriented to perspective of
Linux itself and the vendor resets are oriented towards behavior of the
SoC.

Thanks,
Elliot