[5/8] firmware: qcom: scm: Use atomic SCM for cold boot
diff mbox

Message ID 1461363432-5730-6-git-send-email-andy.gross@linaro.org
State New, archived
Headers show

Commit Message

Andy Gross April 22, 2016, 10:17 p.m. UTC
This patch changes the cold_set_boot_addr function to use atomic SCM
calls.  This removes the need for memory allocation and instead places
all arguments in registers.

Signed-off-by: Andy Gross <andy.gross@linaro.org>
---
 drivers/firmware/qcom_scm-32.c | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

Comments

Bjorn Andersson April 22, 2016, 11:50 p.m. UTC | #1
On Fri 22 Apr 15:17 PDT 2016, Andy Gross wrote:

> This patch changes the cold_set_boot_addr function to use atomic SCM
> calls.  This removes the need for memory allocation and instead places
> all arguments in registers.
> 
> Signed-off-by: Andy Gross <andy.gross@linaro.org>
> ---
>  drivers/firmware/qcom_scm-32.c | 40 ++++++++++++++++++++++++++--------------
>  1 file changed, 26 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
[..]
>  /*
>   * Set the cold/warm boot address for one of the CPU cores.
>   */
> -static int qcom_scm_set_boot_addr(u32 addr, int flags)
> +static int qcom_scm_set_boot_addr(u32 addr, int flags, bool do_atomic)
>  {
>  	struct {
>  		__le32 flags;
>  		__le32 addr;
>  	} cmd;
>  
> -	cmd.addr = cpu_to_le32(addr);
> -	cmd.flags = cpu_to_le32(flags);
> -	return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
> -			&cmd, sizeof(cmd), NULL, 0);
> +	if (do_atomic) {
> +		return qcom_scm_call_atomic(QCOM_SCM_SVC_BOOT,
> +					    QCOM_SCM_BOOT_ADDR, 2, flags, addr);
> +	} else {
> +
> +		cmd.addr = cpu_to_le32(addr);
> +		cmd.flags = cpu_to_le32(flags);
> +
> +		return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
> +				     &cmd, sizeof(cmd), NULL, 0);
> +	}

I would prefer that you split this into two functions, rather than
hiding two functions bodies in one function.

Perhaps qcom_scm_set_boot_addr and qcom_scm_set_boot_addr_atomic?

>  }
>  

Regards,
Bjorn
Andy Gross April 23, 2016, 4:46 a.m. UTC | #2
On Fri, Apr 22, 2016 at 04:50:05PM -0700, Bjorn Andersson wrote:
> On Fri 22 Apr 15:17 PDT 2016, Andy Gross wrote:
> 
> > This patch changes the cold_set_boot_addr function to use atomic SCM
> > calls.  This removes the need for memory allocation and instead places
> > all arguments in registers.
> > 
> > Signed-off-by: Andy Gross <andy.gross@linaro.org>
> > ---
> >  drivers/firmware/qcom_scm-32.c | 40 ++++++++++++++++++++++++++--------------
> >  1 file changed, 26 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
> [..]
> >  /*
> >   * Set the cold/warm boot address for one of the CPU cores.
> >   */
> > -static int qcom_scm_set_boot_addr(u32 addr, int flags)
> > +static int qcom_scm_set_boot_addr(u32 addr, int flags, bool do_atomic)
> >  {
> >  	struct {
> >  		__le32 flags;
> >  		__le32 addr;
> >  	} cmd;
> >  
> > -	cmd.addr = cpu_to_le32(addr);
> > -	cmd.flags = cpu_to_le32(flags);
> > -	return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
> > -			&cmd, sizeof(cmd), NULL, 0);
> > +	if (do_atomic) {
> > +		return qcom_scm_call_atomic(QCOM_SCM_SVC_BOOT,
> > +					    QCOM_SCM_BOOT_ADDR, 2, flags, addr);
> > +	} else {
> > +
> > +		cmd.addr = cpu_to_le32(addr);
> > +		cmd.flags = cpu_to_le32(flags);
> > +
> > +		return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
> > +				     &cmd, sizeof(cmd), NULL, 0);
> > +	}
> 
> I would prefer that you split this into two functions, rather than
> hiding two functions bodies in one function.
> 
> Perhaps qcom_scm_set_boot_addr and qcom_scm_set_boot_addr_atomic?

Fair enough.  It does get a little contrived when you start throwing the extra
options in there.

Patch
diff mbox

diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
index 0d2a3f8..f596091 100644
--- a/drivers/firmware/qcom_scm-32.c
+++ b/drivers/firmware/qcom_scm-32.c
@@ -294,34 +294,39 @@  out:
 				(n & 0xf))
 
 /**
- * qcom_scm_call_atomic1() - Send an atomic SCM command with one argument
+ * qcom_scm_call_atomic() - Send an atomic SCM command with one argument
  * @svc_id: service identifier
  * @cmd_id: command identifier
+ * @arglen: number of arguments
  * @arg1: first argument
+ * @arg2: second argument (optional - fill with 0 if unused)
  *
  * This shall only be used with commands that are guaranteed to be
  * uninterruptable, atomic and SMP safe.
  */
-static s32 qcom_scm_call_atomic1(u32 svc, u32 cmd, u32 arg1)
+static s32 qcom_scm_call_atomic(u32 svc, u32 cmd, u32 arglen, u32 arg1,
+				u32 arg2)
 {
 	int context_id;
 
-	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, 1);
+	register u32 r0 asm("r0") = SCM_ATOMIC(svc, cmd, arglen);
 	register u32 r1 asm("r1") = (u32)&context_id;
 	register u32 r2 asm("r2") = arg1;
+	register u32 r3 asm("r3") = arg2;
 
 	asm volatile(
 			__asmeq("%0", "r0")
 			__asmeq("%1", "r0")
 			__asmeq("%2", "r1")
 			__asmeq("%3", "r2")
+			__asmeq("%4", "r3")
 #ifdef REQUIRES_SEC
 			".arch_extension sec\n"
 #endif
 			"smc    #0      @ switch to secure world\n"
 			: "=r" (r0)
-			: "r" (r0), "r" (r1), "r" (r2)
-			: "r3");
+			: "r" (r0), "r" (r1), "r" (r2), "r" (r3)
+			);
 	return r0;
 }
 
@@ -364,17 +369,24 @@  EXPORT_SYMBOL(qcom_scm_get_version);
 /*
  * Set the cold/warm boot address for one of the CPU cores.
  */
-static int qcom_scm_set_boot_addr(u32 addr, int flags)
+static int qcom_scm_set_boot_addr(u32 addr, int flags, bool do_atomic)
 {
 	struct {
 		__le32 flags;
 		__le32 addr;
 	} cmd;
 
-	cmd.addr = cpu_to_le32(addr);
-	cmd.flags = cpu_to_le32(flags);
-	return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
-			&cmd, sizeof(cmd), NULL, 0);
+	if (do_atomic) {
+		return qcom_scm_call_atomic(QCOM_SCM_SVC_BOOT,
+					    QCOM_SCM_BOOT_ADDR, 2, flags, addr);
+	} else {
+
+		cmd.addr = cpu_to_le32(addr);
+		cmd.flags = cpu_to_le32(flags);
+
+		return qcom_scm_call(QCOM_SCM_SVC_BOOT, QCOM_SCM_BOOT_ADDR,
+				     &cmd, sizeof(cmd), NULL, 0);
+	}
 }
 
 /**
@@ -406,7 +418,7 @@  int __qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
 			set_cpu_present(cpu, false);
 	}
 
-	return qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
+	return qcom_scm_set_boot_addr(virt_to_phys(entry), flags, true);
 }
 
 /**
@@ -437,7 +449,7 @@  int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
 	if (!flags)
 		return 0;
 
-	ret = qcom_scm_set_boot_addr(virt_to_phys(entry), flags);
+	ret = qcom_scm_set_boot_addr(virt_to_phys(entry), flags, false);
 	if (!ret) {
 		for_each_cpu(cpu, cpus)
 			qcom_scm_wb[cpu].entry = entry;
@@ -456,8 +468,8 @@  int __qcom_scm_set_warm_boot_addr(void *entry, const cpumask_t *cpus)
  */
 void __qcom_scm_cpu_power_down(u32 flags)
 {
-	qcom_scm_call_atomic1(QCOM_SCM_SVC_BOOT, QCOM_SCM_CMD_TERMINATE_PC,
-			flags & QCOM_SCM_FLUSH_FLAG_MASK);
+	qcom_scm_call_atomic(QCOM_SCM_SVC_BOOT, QCOM_SCM_CMD_TERMINATE_PC, 1,
+			flags & QCOM_SCM_FLUSH_FLAG_MASK, 0);
 }
 
 int __qcom_scm_is_call_available(u32 svc_id, u32 cmd_id)