firmware: qcom: scm: smc: switch to using the SCM allocator

We need to allocate, map and pass a buffer to the trustzone if we have
more than 4 arguments for a given SCM call. Let's use the new TrustZone
allocator for that memory and shrink the code in process.

As this code lives in a different compilation unit than the rest of the
SCM code, we need to provide a helper in the form of
qcom_scm_get_tzmem_pool() that allows the SMC low-level routines to
access the SCM memory pool.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
Tested-by: Deepti Jaggi <quic_djaggi@quicinc.com> #sa8775p-ride
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
Link: https://lore.kernel.org/r/20240527-shm-bridge-v10-4-ce7afaa58d3a@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

diff --git a/drivers/firmware/qcom/qcom_scm-smc.c b/drivers/firmware/qcom/qcom_scm-smc.c
index 16cf88a..dca5f3f 100644 (file)
--- a/drivers/firmware/qcom/qcom_scm-smc.c
+++ b/drivers/firmware/qcom/qcom_scm-smc.c
@@ -2,6 +2,7 @@
 /* Copyright (c) 2015,2019 The Linux Foundation. All rights reserved.
  */
 
+#include <linux/cleanup.h>
 #include <linux/io.h>
 #include <linux/errno.h>
 #include <linux/delay.h>
@@ -9,6 +10,7 @@
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/firmware/qcom/qcom_tzmem.h>
 #include <linux/arm-smccc.h>
 #include <linux/dma-mapping.h>
 
@@ -150,11 +152,10 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
                   enum qcom_scm_convention qcom_convention,
                   struct qcom_scm_res *res, bool atomic)
 {
+       struct qcom_tzmem_pool *mempool = qcom_scm_get_tzmem_pool();
        int arglen = desc->arginfo & 0xf;
        int i, ret;
-       dma_addr_t args_phys = 0;
-       void *args_virt = NULL;
-       size_t alloc_len;
+       void *args_virt __free(qcom_tzmem) = NULL;
        gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
        u32 smccc_call_type = atomic ? ARM_SMCCC_FAST_CALL : ARM_SMCCC_STD_CALL;
        u32 qcom_smccc_convention = (qcom_convention == SMC_CONVENTION_ARM_32) ?
@@ -172,9 +173,9 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
                smc.args[i + SCM_SMC_FIRST_REG_IDX] = desc->args[i];
 
        if (unlikely(arglen > SCM_SMC_N_REG_ARGS)) {
-               alloc_len = SCM_SMC_N_EXT_ARGS * sizeof(u64);
-               args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag);
-
+               args_virt = qcom_tzmem_alloc(mempool,
+                                            SCM_SMC_N_EXT_ARGS * sizeof(u64),
+                                            flag);
                if (!args_virt)
                        return -ENOMEM;
 
@@ -192,25 +193,10 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
                                                      SCM_SMC_FIRST_EXT_IDX]);
                }
 
-               args_phys = dma_map_single(dev, args_virt, alloc_len,
-                                          DMA_TO_DEVICE);
-
-               if (dma_mapping_error(dev, args_phys)) {
-                       kfree(args_virt);
-                       return -ENOMEM;
-               }
-
-               smc.args[SCM_SMC_LAST_REG_IDX] = args_phys;
+               smc.args[SCM_SMC_LAST_REG_IDX] = qcom_tzmem_to_phys(args_virt);
        }
 
-       /* ret error check follows after args_virt cleanup*/
        ret = __scm_smc_do(dev, &smc, &smc_res, atomic);
-
-       if (args_virt) {
-               dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
-               kfree(args_virt);
-       }
-
        if (ret)
                return ret;
 

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 7ccbd87..1e873e8 100644 (file)
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -203,6 +203,11 @@ static void qcom_scm_bw_disable(void)
 enum qcom_scm_convention qcom_scm_convention = SMC_CONVENTION_UNKNOWN;
 static DEFINE_SPINLOCK(scm_query_lock);
 
+struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void)
+{
+       return __scm->mempool;
+}
+
 static enum qcom_scm_convention __get_convention(void)
 {
        unsigned long flags;

diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h
index 484e030..628f5ef 100644 (file)
--- a/drivers/firmware/qcom/qcom_scm.h
+++ b/drivers/firmware/qcom/qcom_scm.h
@@ -5,6 +5,7 @@
 #define __QCOM_SCM_INT_H
 
 struct device;
+struct qcom_tzmem_pool;
 
 enum qcom_scm_convention {
        SMC_CONVENTION_UNKNOWN,
@@ -78,6 +79,8 @@ int scm_legacy_call_atomic(struct device *dev, const struct qcom_scm_desc *desc,
 int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
                    struct qcom_scm_res *res);
 
+struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
+
 #define QCOM_SCM_SVC_BOOT              0x01
 #define QCOM_SCM_BOOT_SET_ADDR         0x01
 #define QCOM_SCM_BOOT_TERMINATE_PC     0x02