On 02/18/2016 11:23 AM, Paul Walmsley wrote:

On Thu, 18 Feb 2016, Sekhar Nori wrote:

quoted

On Friday 12 February 2016 10:50 PM, Suman Anna wrote:

quoted

Sekhar,
Will you be following up with above suggestion since Kishon is gonna be out?

Alright, noticed this action for me :) Went through the thread, and 
looks like this is what we want to see?

Thanks Sekhar.  Did you try the driver unbind/bind sequence a few times to 
ensure that works, per Suman's earlier E-mail? 

Should work since the assert/deassert is now out of the driver
probe/remove path and is done only at init time, but will let Sekhar
confirm this.

Suman, is there any further testing that you are planning to do on this 
patch?

No, nothing on my side, since this is now localized to PCIe and only on
DRA7xx. I will relook at your custom flags solution when I consolidate
the reset for OMAP IOMMUs and remoteprocs, that looks promising to
remove the pdata quirks for resets or dependencies in drivers against a
reset API.

- Paul

quoted

Thanks,
Sekhar

---8<---

quoted

From e3ba368f2235e1bf38a22ba8ea4e5c12aaafda19 Mon Sep 17 00:00:00 2001

Message-Id: [off-list ref]
From: Sekhar Nori <redacted>
Date: Thu, 18 Feb 2016 16:49:56 +0530
Subject: [PATCH 1/1] ARM: DRA7: hwmod: Add custom reset handler for PCIeSS

Add a custom reset handler for DRA7x PCIeSS. This
handler is required to deassert PCIe hardreset lines
after they have been asserted.

This enables the PCIe driver to access registers after
PCIeSS has been runtime enabled without having to
deassert hardreset lines itself.

With this patch applied, used lspci to make sure
connected PCIe device enumerates on DRA74x and DRA72x
EVMs.

Yep, this is what I had in mind. Glad that it resolves the issue.

quoted

Signed-off-by: Sekhar Nori <redacted>
---
Applies to tag for-v4.6/omap-hwmod-a of Paul W's tree.

 arch/arm/mach-omap2/omap_hwmod_7xx_data.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
index b61355e2a771..252b74633e31 100644
--- a/arch/arm/mach-omap2/omap_hwmod_7xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_7xx_data.c

@@ -1526,8 +1526,31 @@ static struct omap_hwmod dra7xx_ocp2scp3_hwmod = {
  *
  */
 
+/*
+ * As noted in documentation for _reset() in omap_hwmod.c, the stock reset
+ * functionality of OMAP HWMOD layer does not deassert the hardreset lines
+ * associated with an IP automatically leaving the driver to handle that
+ * by itself. This does not work for PCIeSS which needs the reset lines
+ * deasserted for the driver to start accessing registers.
+ *
+ * We use a PCIeSS HWMOD class specific reset handler to deassert the hardreset
+ * lines after asserting them.
+ */
+static int dra7xx_pciess_reset(struct omap_hwmod *oh)
+{
+	int i;
+
+	for (i = 0; i < oh->rst_lines_cnt; i++) {
+		omap_hwmod_assert_hardreset(oh, oh->rst_lines[i].name);
+		omap_hwmod_deassert_hardreset(oh, oh->rst_lines[i].name);

Hmm, ignoring return values??

regards
Suman

quoted

+	}
+
+	return 0;
+}
+
 static struct omap_hwmod_class dra7xx_pciess_hwmod_class = {
 	.name	= "pcie",
+	.reset	= dra7xx_pciess_reset,
 };
 
 /* pcie1 */
-- 
2.6.3

- Paul