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authorElliot Berman <eberman@codeaurora.org>2020-01-07 13:04:26 -0800
committerBjorn Andersson <bjorn.andersson@linaro.org>2020-01-07 22:14:43 -0800
commit9a434cee773ae15309ac225f27551b5492618e4a (patch)
tree26d7deff138efa039629a0611ada779626d552e5 /drivers/firmware/qcom_scm-smc.c
parent57d3b816718c1cf832e2929a754da3564c6127cc (diff)
firmware: qcom_scm: Dynamically support SMCCC and legacy conventions
Dynamically support SMCCCC and legacy conventions by detecting which convention to use at runtime. qcom_scm_call_atomic and qcom_scm_call can then be moved in qcom_scm.c and use underlying convention backend as appropriate. Thus, rename qcom_scm-64,-32 to reflect that they are backends for -smc and -legacy, respectively. Also add support for making SCM calls earlier than when SCM driver probes to support use cases such as qcom_scm_set_cold_boot_addr. Support is added by lazily initializing the convention and guarding the query with a spin lock. The limitation of these early SCM calls is that they cannot use DMA, as in the case of >4 arguments for SMC convention and any non-atomic call for legacy convention. Tested-by: Brian Masney <masneyb@onstation.org> # arm32 Tested-by: Stephan Gerhold <stephan@gerhold.net> Signed-off-by: Elliot Berman <eberman@codeaurora.org> Link: https://lore.kernel.org/r/1578431066-19600-18-git-send-email-eberman@codeaurora.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Diffstat (limited to 'drivers/firmware/qcom_scm-smc.c')
-rw-r--r--drivers/firmware/qcom_scm-smc.c151
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/firmware/qcom_scm-smc.c b/drivers/firmware/qcom_scm-smc.c
new file mode 100644
index 000000000000..497c13ba98d6
--- /dev/null
+++ b/drivers/firmware/qcom_scm-smc.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2015,2019 The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/qcom_scm.h>
+#include <linux/arm-smccc.h>
+#include <linux/dma-mapping.h>
+
+#include "qcom_scm.h"
+
+/**
+ * struct arm_smccc_args
+ * @args: The array of values used in registers in smc instruction
+ */
+struct arm_smccc_args {
+ unsigned long args[8];
+};
+
+static DEFINE_MUTEX(qcom_scm_lock);
+
+#define QCOM_SCM_EBUSY_WAIT_MS 30
+#define QCOM_SCM_EBUSY_MAX_RETRY 20
+
+#define SCM_SMC_N_REG_ARGS 4
+#define SCM_SMC_FIRST_EXT_IDX (SCM_SMC_N_REG_ARGS - 1)
+#define SCM_SMC_N_EXT_ARGS (MAX_QCOM_SCM_ARGS - SCM_SMC_N_REG_ARGS + 1)
+#define SCM_SMC_FIRST_REG_IDX 2
+#define SCM_SMC_LAST_REG_IDX (SCM_SMC_FIRST_REG_IDX + SCM_SMC_N_REG_ARGS - 1)
+
+static void __scm_smc_do_quirk(const struct arm_smccc_args *smc,
+ struct arm_smccc_res *res)
+{
+ unsigned long a0 = smc->args[0];
+ struct arm_smccc_quirk quirk = { .id = ARM_SMCCC_QUIRK_QCOM_A6 };
+
+ quirk.state.a6 = 0;
+
+ do {
+ arm_smccc_smc_quirk(a0, smc->args[1], smc->args[2],
+ smc->args[3], smc->args[4], smc->args[5],
+ quirk.state.a6, smc->args[7], res, &quirk);
+
+ if (res->a0 == QCOM_SCM_INTERRUPTED)
+ a0 = res->a0;
+
+ } while (res->a0 == QCOM_SCM_INTERRUPTED);
+}
+
+static void __scm_smc_do(const struct arm_smccc_args *smc,
+ struct arm_smccc_res *res, bool atomic)
+{
+ int retry_count = 0;
+
+ if (atomic) {
+ __scm_smc_do_quirk(smc, res);
+ return;
+ }
+
+ do {
+ mutex_lock(&qcom_scm_lock);
+
+ __scm_smc_do_quirk(smc, res);
+
+ mutex_unlock(&qcom_scm_lock);
+
+ if (res->a0 == QCOM_SCM_V2_EBUSY) {
+ if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
+ break;
+ msleep(QCOM_SCM_EBUSY_WAIT_MS);
+ }
+ } while (res->a0 == QCOM_SCM_V2_EBUSY);
+}
+
+int scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
+ struct qcom_scm_res *res, bool atomic)
+{
+ int arglen = desc->arginfo & 0xf;
+ int i;
+ dma_addr_t args_phys = 0;
+ void *args_virt = NULL;
+ size_t alloc_len;
+ 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_scm_convention == SMC_CONVENTION_ARM_32) ?
+ ARM_SMCCC_SMC_32 : ARM_SMCCC_SMC_64;
+ struct arm_smccc_res smc_res;
+ struct arm_smccc_args smc = {0};
+
+ smc.args[0] = ARM_SMCCC_CALL_VAL(
+ smccc_call_type,
+ qcom_smccc_convention,
+ desc->owner,
+ SCM_SMC_FNID(desc->svc, desc->cmd));
+ smc.args[1] = desc->arginfo;
+ for (i = 0; i < SCM_SMC_N_REG_ARGS; i++)
+ 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);
+
+ if (!args_virt)
+ return -ENOMEM;
+
+ if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
+ __le32 *args = args_virt;
+
+ for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++)
+ args[i] = cpu_to_le32(desc->args[i +
+ SCM_SMC_FIRST_EXT_IDX]);
+ } else {
+ __le64 *args = args_virt;
+
+ for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++)
+ args[i] = cpu_to_le64(desc->args[i +
+ 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;
+ }
+
+ __scm_smc_do(&smc, &smc_res, atomic);
+
+ if (args_virt) {
+ dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
+ kfree(args_virt);
+ }
+
+ if (res) {
+ res->result[0] = smc_res.a1;
+ res->result[1] = smc_res.a2;
+ res->result[2] = smc_res.a3;
+ }
+
+ return (long)smc_res.a0 ? qcom_scm_remap_error(smc_res.a0) : 0;
+}