memory: mtk-smi: Add enable IOMMU SMC command for MM master

For concerns about security, the register to enable/disable IOMMU of
SMI LARB should only be configured in secure world. Thus, we add some
SMC command for multimedia master to enable/disable MM IOMMU in ATF by
setting the register of SMI LARB. This function is prepared for MT8188.

Signed-off-by: Chengci.Xu <[e-mail]>
Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/memory/mtk-smi.c

···
  * Copyright (c) 2015-2016 MediaTek Inc.
  * Author: Yong Wu <[e-mail]>
  */
+#include <linux/arm-smccc.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/device.h>
···
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/soc/mediatek/mtk_sip_svc.h>
 #include <soc/mediatek/smi.h>
 #include <dt-bindings/memory/mt2701-larb-port.h>
 #include <dt-bindings/memory/mtk-memory-port.h>
···
 #define MTK_SMI_FLAG_THRT_UPDATE	BIT(0)
 #define MTK_SMI_FLAG_SW_FLAG		BIT(1)
 #define MTK_SMI_FLAG_SLEEP_CTL		BIT(2)
+#define MTK_SMI_FLAG_CFG_PORT_SEC_CTL	BIT(3)
 #define MTK_SMI_CAPS(flags, _x)		(!!((flags) & (_x)))
 
 struct mtk_smi_reg_pair {
···
 	struct mtk_smi_larb *larb = dev_get_drvdata(dev);
 	u32 reg, flags_general = larb->larb_gen->flags_general;
 	const u8 *larbostd = larb->larb_gen->ostd ? larb->larb_gen->ostd[larb->larbid] : NULL;
+	struct arm_smccc_res res;
 	int i;
 
 	if (BIT(larb->larbid) & larb->larb_gen->larb_direct_to_common_mask)
···
 
 	for (i = 0; i < SMI_LARB_PORT_NR_MAX && larbostd && !!larbostd[i]; i++)
 		writel_relaxed(larbostd[i], larb->base + SMI_LARB_OSTDL_PORTx(i));
+
+	/*
+	 * When mmu_en bits are in security world, the bank_sel still is in the
+	 * LARB_NONSEC_CON below. And the mmu_en bits of LARB_NONSEC_CON have no
+	 * effect in this case.
+	 */
+	if (MTK_SMI_CAPS(flags_general, MTK_SMI_FLAG_CFG_PORT_SEC_CTL)) {
+		arm_smccc_smc(MTK_SIP_KERNEL_IOMMU_CONTROL, IOMMU_ATF_CMD_CONFIG_SMI_LARB,
+			      larb->larbid, *larb->mmu, 0, 0, 0, 0, &res);
+		if (res.a0 != 0) {
+			dev_err(dev, "Enable iommu fail, ret %ld\n", res.a0);
+			return -EINVAL;
+		}
+	}
 
 	for_each_set_bit(i, (unsigned long *)larb->mmu, 32) {
 		reg = readl_relaxed(larb->base + SMI_LARB_NONSEC_CON(i));

include/linux/soc/mediatek/mtk_sip_svc.h

···
 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, MTK_SIP_SMC_CONVENTION, \
 			   ARM_SMCCC_OWNER_SIP, fn_id)
 
+/* IOMMU related SMC call */
+#define MTK_SIP_KERNEL_IOMMU_CONTROL	MTK_SIP_SMC_CMD(0x514)
+
 #endif

include/soc/mediatek/smi.h

···
 
 #if IS_ENABLED(CONFIG_MTK_SMI)
 
+enum iommu_atf_cmd {
+	IOMMU_ATF_CMD_CONFIG_SMI_LARB,		/* For mm master to en/disable iommu */
+	IOMMU_ATF_CMD_MAX,
+};
+
 #define MTK_SMI_MMU_EN(port)	BIT(port)
 
 struct mtk_smi_larb_iommu {