Re: [PATCH v3 1/7] firmware: rockchip: sip: Add rockchip SIP runtime service

From: Sudeep Holla
Date: Mon Jul 25 2016 - 13:36:17 EST

On 22/07/16 21:50, Heiko Stübner wrote:
Hi again,

one bigger thing I noticed only now.

Am Freitag, 22. Juli 2016, 17:07:14 schrieben Sie:
diff --git a/drivers/firmware/rockchip_sip.c
b/drivers/firmware/rockchip_sip.c new file mode 100644
index 0000000..7756af9
--- /dev/null
+++ b/drivers/firmware/rockchip_sip.c
@@ -0,0 +1,64 @@
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2016 ARM Limited
+ */
+#include <linux/errno.h>
+#include <linux/linkage.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/printk.h>
+#include "rockchip_sip.h"
+typedef unsigned long (psci_fn)(unsigned long, unsigned long,
+ unsigned long, unsigned long);
+asmlinkage psci_fn __invoke_psci_fn_smc;
+#define CONFIG_DRAM_INIT 0x00
+#define CONFIG_DRAM_SET_RATE 0x01
+#define CONFIG_DRAM_SET_AT_SR 0x03
+#define CONFIG_DRAM_GET_BW 0x04
+#define CONFIG_DRAM_GET_RATE 0x05
+#define CONFIG_DRAM_CLR_IRQ 0x06
+uint64_t sip_smc_ddr_init(void)
+ return __invoke_psci_fn_smc(SIP_DDR_FREQ, 0,

I don't think that is legal to use. For one this function itself is declared
static in the psci code - most likely for a specific reason.

And also if anything invoke_psci_fn would hold the correct pointer depending
on the calling method.

But as said above, accessing psci static stuff is most likely wrong. Maybe the
two psci people I've included can tell us how this is to be accessed.

Thanks Heiko for looping us in this thread.

The feature being added in this series is completely out of scope of
PSCI specification and hence PSCI can't be used. Firstly we need to
audit if these are need in Linux and why they can't be handled within
the existing PSCI APIs. But yes, this series is misuse of PSCI.

I also see to know that ARM Trusted Firmware community has not accepted
this PSCI approach, so this patches are useless without that.

If they are still needed they need to make use of SMC Calling Convention
(arm_smccc_smc). Either make these smc function identifiers standard on
their platforms and use them directly in the driver. If they tend to
change too much across their platforms, use the DT approach with
appropriate bindings.