[PATCH net-next 3/6] net: ipa: disable misc clock gating for IPA v3.1

[Alex Elder <elder@linaro.org>]

For IPA v3.1, a workaround is needed to disable gating on a MISC
clock.  I have no further explanation, but this is what the
downstream code (msm-4.4) does.

This was suggested in a patch from AngeloGioacchino Del Regno.

Link: https://lore.kernel.org/netdev/20210211175015.200772-2-angelogioacchino.delregno@somainline.org
Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/ipa_main.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c
index f82130db32f6d..20a83c7f671f3 100644
--- a/drivers/net/ipa/ipa_main.c
+++ b/drivers/net/ipa/ipa_main.c
@@ -400,16 +400,20 @@ static void ipa_hardware_config(struct ipa *ipa, const struct ipa_data *data)
 
 	/* Implement some hardware workarounds */
 	if (version >= IPA_VERSION_4_0 && version < IPA_VERSION_4_5) {
-		/* Enable open global clocks (not needed for IPA v4.5) */
-		val = GLOBAL_FMASK;
-		val |= GLOBAL_2X_CLK_FMASK;
-		iowrite32(val, ipa->reg_virt + IPA_REG_CLKON_CFG_OFFSET);
-
 		/* Disable PA mask to allow HOLB drop */
 		val = ioread32(ipa->reg_virt + IPA_REG_TX_CFG_OFFSET);
 		val &= ~PA_MASK_EN_FMASK;
 		iowrite32(val, ipa->reg_virt + IPA_REG_TX_CFG_OFFSET);
+
+		/* Enable open global clocks in the CLKON configuration */
+		val = GLOBAL_FMASK | GLOBAL_2X_CLK_FMASK;
+	} else if (version == IPA_VERSION_3_1) {
+		val = MISC_FMASK;	/* Disable MISC clock gating */
+	} else {
+		val = 0;		/* No CLKON configuration needed */
 	}
+	if (val)
+		iowrite32(val, ipa->reg_virt + IPA_REG_CLKON_CFG_OFFSET);
 
 	ipa_hardware_config_comp(ipa);
 
-- 
2.27.0