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Commit 356b47bd authored by Abhijeet Dharmapurikar's avatar Abhijeet Dharmapurikar Committed by Stephen Boyd
Browse files

msm: krait-regulator: switch mode on the same cpu 



The driver currently runs LDO-BHS mode switches while possibly
running on a different CPU. The CPU for which the mode switch is
issued could be running its SPM sequence as a part of going in or
coming out of power collapse. The LDO-BHS switching executed from a
different CPU could race with the mode switches done in SPM sequence
leaving the CPU in a bad state.

Fix this by executing LDO-BHS mode switches on the target CPU. This
guarantees that the SPM sequence won't be running on that CPU while
changing modes.

CRs-Fixed: 523449
Change-Id: I863ce3bcd6dd9ba3155c4573071f01e7a020ef48
Signed-off-by: default avatarAbhijeet Dharmapurikar <adharmap@codeaurora.org>
parent 62a91ba9

arch/arm/mach-msm/krait-regulator.c

+26 −11
Original line number Diff line number Diff line
@@ -591,10 +591,10 @@ static unsigned int krait_power_get_mode(struct regulator_dev *rdev) 
	return kvreg->mode;

}



static int switch_to_using_hs(struct krait_power_vreg *kvreg)

static void __switch_to_using_bhs(void *info)

{

	if (kvreg->mode == HS_MODE)

		return 0;

	struct krait_power_vreg *kvreg = info;



	/* enable bhs */

	if (version > KPSS_VERSION_2P0) {

		krait_masked_write(kvreg, APC_PWR_GATE_MODE,
@@ -648,21 +648,18 @@ static int switch_to_using_hs(struct krait_power_vreg *kvreg) 


	kvreg->mode = HS_MODE;

	pr_debug("%s using BHS\n", kvreg->name);

	return 0;

}



static int switch_to_using_ldo(struct krait_power_vreg *kvreg)

static void __switch_to_using_ldo(void *info)

{

	if (kvreg->mode == LDO_MODE

		&& get_krait_ldo_uv(kvreg) == kvreg->uV - kvreg->ldo_delta_uV)

		return 0;

	struct krait_power_vreg *kvreg = info;



	/*

	 * if the krait is in ldo mode and a voltage change is requested on the

	 * ldo switch to using hs before changing ldo voltage

	 */

	if (kvreg->mode == LDO_MODE)

		switch_to_using_hs(kvreg);

		__switch_to_using_bhs(kvreg);



	set_krait_ldo_uv(kvreg, kvreg->uV - kvreg->ldo_delta_uV);

	if (version > KPSS_VERSION_2P0) {
@@ -701,7 +698,25 @@ static int switch_to_using_ldo(struct krait_power_vreg *kvreg) 


	kvreg->mode = LDO_MODE;

	pr_debug("%s using LDO\n", kvreg->name);

}



static int switch_to_using_ldo(struct krait_power_vreg *kvreg)

{

	if (kvreg->mode == LDO_MODE

		&& get_krait_ldo_uv(kvreg) == kvreg->uV - kvreg->ldo_delta_uV)

		return 0;



	return smp_call_function_single(kvreg->cpu_num,

			__switch_to_using_ldo, kvreg, 1);

}



static int switch_to_using_bhs(struct krait_power_vreg *kvreg)

{

	if (kvreg->mode == HS_MODE)

		return 0;



	return smp_call_function_single(kvreg->cpu_num,

			__switch_to_using_bhs, kvreg, 1);

}



static int set_pmic_gang_voltage(struct pmic_gang_vreg *pvreg, int uV)
@@ -772,7 +787,7 @@ static int configure_ldo_or_hs_all(struct krait_power_vreg *from, int vmax) 
				return rc;

			}

		} else {

			rc = switch_to_using_hs(kvreg);

			rc = switch_to_using_bhs(kvreg);

			if (rc < 0) {

				pr_err("could not switch %s to hs rc = %d\n",

							kvreg->name, rc);