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firmware: qcom: scm: Fix interrupted SCM calls

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This patch adds a Qualcomm specific quirk to the arm_smccc_smc call.

On Qualcomm ARM64 platforms, the SMC call can return before it has
completed.  If this occurs, the call can be restarted, but it requires
using the returned session ID value from the interrupted SMC call.

The quirk stores off the session ID from the interrupted call in the
quirk structure so that it can be used by the caller.

This patch folds in a fix given by Sricharan R:
https://lkml.org/lkml/2016/9/28/272

Signed-off-by: Andy Gross <andy.gross@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Andy Gross 2017-02-01 11:28:28 -06:00 committed by Will Deacon
parent 680a0873e1
commit 82bcd08702
3 changed files with 26 additions and 7 deletions
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9
arch/arm64/kernel/smccc-call.S
View File

@ -12,6 +12,7 @@
*
*/
#include <linux/linkage.h>
#include <linux/arm-smccc.h>
#include <asm/asm-offsets.h>
.macro SMCCC instr
@ -20,7 +21,13 @@
ldr x4, [sp]
stp x0, x1, [x4, #ARM_SMCCC_RES_X0_OFFS]
stp x2, x3, [x4, #ARM_SMCCC_RES_X2_OFFS]
ret
ldr x4, [sp, #8]
cbz x4, 1f /* no quirk structure */
ldr x9, [x4, #ARM_SMCCC_QUIRK_ID_OFFS]
cmp x9, #ARM_SMCCC_QUIRK_QCOM_A6
b.ne 1f
str x6, [x4, ARM_SMCCC_QUIRK_STATE_OFFS]
1: ret
.cfi_endproc
.endm

13
drivers/firmware/qcom_scm-64.c
View File

@ -91,6 +91,7 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
dma_addr_t args_phys = 0;
void *args_virt = NULL;
size_t alloc_len;
struct arm_smccc_quirk quirk = {.id = ARM_SMCCC_QUIRK_QCOM_A6};
if (unlikely(arglen > N_REGISTER_ARGS)) {
alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
@ -131,10 +132,16 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
qcom_smccc_convention,
ARM_SMCCC_OWNER_SIP, fn_id);
quirk.state.a6 = 0;
do {
arm_smccc_smc(cmd, desc->arginfo, desc->args[0],
desc->args[1], desc->args[2], x5, 0, 0,
res);
arm_smccc_smc_quirk(cmd, desc->arginfo, desc->args[0],
desc->args[1], desc->args[2], x5,
quirk.state.a6, 0, res, &quirk);
if (res->a0 == QCOM_SCM_INTERRUPTED)
cmd = res->a0;
} while (res->a0 == QCOM_SCM_INTERRUPTED);
mutex_unlock(&qcom_scm_lock);

11
include/linux/arm-smccc.h
View File

@ -14,9 +14,6 @@
#ifndef __LINUX_ARM_SMCCC_H
#define __LINUX_ARM_SMCCC_H
#include <linux/linkage.h>
#include <linux/types.h>
/*
* This file provides common defines for ARM SMC Calling Convention as
* specified in
@ -60,6 +57,13 @@
#define ARM_SMCCC_OWNER_TRUSTED_OS 50
#define ARM_SMCCC_OWNER_TRUSTED_OS_END 63
#define ARM_SMCCC_QUIRK_NONE 0
#define ARM_SMCCC_QUIRK_QCOM_A6 1 /* Save/restore register a6 */
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
#include <linux/types.h>
/**
* struct arm_smccc_res - Result from SMC/HVC call
* @a0-a3 result values from registers 0 to 3
@ -125,4 +129,5 @@ asmlinkage void __arm_smccc_hvc(unsigned long a0, unsigned long a1,
#define arm_smccc_hvc_quirk(...) __arm_smccc_hvc(__VA_ARGS__)
#endif /*__ASSEMBLY__*/
#endif /*__LINUX_ARM_SMCCC_H*/