Received-SPF: pass (google.com: domain of linux-kernel+bounces-145781-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
From: Frank Li <Frank.Li@nxp.com>
Date: Mon, 15 Apr 2024 15:33:29 -0400
Subject: [PATCH v6 5/5] PCI: dwc: Add generic MSG TLP support for sending
 PME_Turn_Off when system suspend
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-Id: <20240415-pme_msg-v6-5-56dad968ad3a@nxp.com>
References: <20240415-pme_msg-v6-0-56dad968ad3a@nxp.com>
In-Reply-To: <20240415-pme_msg-v6-0-56dad968ad3a@nxp.com>
To: Bjorn Helgaas <bhelgaas@google.com>, Jingoo Han <jingoohan1@gmail.com>, 
 Gustavo Pimentel <gustavo.pimentel@synopsys.com>, 
 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>, 
 Lorenzo Pieralisi <lpieralisi@kernel.org>, 
 =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>, 
 Rob Herring <robh@kernel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
 Conor Dooley <conor+dt@kernel.org>, imx@lists.linux.dev
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, 
 devicetree@vger.kernel.org, Frank Li <Frank.Li@nxp.com>
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?REF3ZW4zY0F2cnE4NEM0aC9PUmt5K2dLTjRaUGsvZStROHBKNEtyWWZyL3Nl?=
 =?utf-8?B?ZkM4VlErWlZDZ1lOc1EvUjFucDl2eGZGUENUbzVPbEJCVEpLdXMyUmpJbzhI?=
 =?utf-8?B?eVRnZXZhU3RlNHFTTHg5RmlXSWhuc3NnOXFuZnFMbDJmWm9oVU5vODQyd1lU?=
 =?utf-8?B?L0RCNFZiR2Z0SHVKZzN2RXFlUTJLUUNIdXRXbGI0UWdVMUJIYklaL3FwT2Jt?=
 =?utf-8?B?a2o1TGs0Q2N1KzROR1R5ZUVHV29FdkJFUlJaZjZjYmIyNmYycjQyKzNSOUtx?=
 =?utf-8?B?cWgrNXlLSUJiWTE2OEJydDZtSkpldnlyZWJINEpTN1NSWU90RGhYNUZHRlI1?=
 =?utf-8?B?d0IrWEc5cFQrc2ozTElrb2N4VkM3OHUrVmhjbmxBeDVSL3pRSXU1SVgyL2w0?=
 =?utf-8?B?UTAzU2txcWdMSTd1OHQ1TmNDLzBXNkNnNXY2NlQ1RVBYU2N3azJnZU1ZSUJt?=
 =?utf-8?B?MlYwaFdNME1ob3g1dkhkeSsyU0RqOVhBWkk1alZYVGxZM01UZlNJamcyNThX?=
 =?utf-8?B?Y1plRHVJSlV4cFBZbTJmK1dKZjlJV2NXKzl0L0RwVW5JY1ROM1phWU5EWFRo?=
 =?utf-8?B?cUxRa0FWQnc2NGgwOG0ydklIc1pPVkJSeG5RcVpvRjhvdXloclpJdUZpMmk5?=
 =?utf-8?B?eXNENWtCbDMrQ0tMUjJpSmxkSEMxWDJuQTBmN3FtdmV0ZFliN1pMRmJQVEpB?=
 =?utf-8?B?M0JOR1U5Qm91ZlJXQjdhTHRUSVVKKzlyRHVzUGtwQWRjZkFFekI2NUkzVHA1?=
 =?utf-8?B?TE5MVFFrYkJ0SEVncDZQcGlMelhmc09sNExMRGhGcGNzNG5PZnRIeVlvQlk1?=
 =?utf-8?B?dm1mZDlQMy91d1p4NnZUUWZEN3ZvV2pEbk1QOU9pRHlwN0pNcXRtdEhBR0g0?=
 =?utf-8?B?bys2c2k0eG5mUUlYTXYwYlVZRitrK3grNGJRbk1RQXpMcDVWaHFqYnJKOVRJ?=
 =?utf-8?B?NWJPbGowYUREWDVXQ0ptQkthTEp5MkI1aGx3dXdIVk1LbHEzMTF3T1R3TkN3?=
 =?utf-8?B?eUFCc1pTblpOSW9QSGwxdUlrVitDeHRqcmJVMHNCU044dE1XWFdIT3VlRytx?=
 =?utf-8?B?TEdLcnhURXc1U1BjMURRenBBR0FPMnFpQUR6ODczZEpaTTEvVk9FcVlUYWV6?=
 =?utf-8?B?TnV3OFUzYnQxWlIrUEFZREVoZHM2V3I5a2tFK2EzaEY3RWd1cEpVZkIyZHpn?=
 =?utf-8?B?ODdXRUpocXQ4VDU4Q1BWejk4SXBnVU8rSFpkYnFjSlg1NUVuczZGZXNKU25S?=
 =?utf-8?B?Y2VPZzdMd20zb21sY0VTWm5BQkZmS2grODlNM3JWNUl3RnppUFcrVlN0RFRN?=
 =?utf-8?B?VW5Kb1pLaTJyaENNVGVXNklGQjF5Vy9qYVdWZS9reDZCbUJhSXA3NjlwaS82?=
 =?utf-8?B?a0ZrYk9GcTRuTmtYczdUcTFWeFd6bVdsREZWMUJaSVJnWnc4MmQ5UHplTnRW?=
 =?utf-8?B?dHRtOTM5SHR1MkdkN1Y1ODBua2o4WG1QSTZ5TG1oeTR0NGt3bnFNejhnUW9F?=
 =?utf-8?B?Y1ZyeFJQYU4rS0hUV0phTTZpMCtFdUlIa2dBZUttZXJoUjBkNUVxeVdzd0JK?=
 =?utf-8?B?cTN1MGp2L0NRME1tbm56THlzaytmQTRrRExXS0Y1YTczb2kzeDlDREkzSDJQ?=
 =?utf-8?B?TXl0Q2NDZzFlcjdrYnZJZDR1dnZGOU5IZWVuS0IvcmpaQVZsOHdyaUhGNzZ4?=
 =?utf-8?B?c0JVN1d1b1d3VjBFcGE0ZjBGWFI1azUxZEdON1hjaEJYdWZoSmVUZ1ZhK0Ru?=
 =?utf-8?B?ck1iUUZjcGVUWkVPVVRNbGI0WU9lcEJGbjdWWkFKSEVZb0xvWThGKzdRT3NT?=
 =?utf-8?B?SUZpY0xOSEZMVlYrdUVaaW53cFdUd1hLdzUzYnNNNVFDWHlqRDFzcyt6OW5i?=
 =?utf-8?B?OWdVcjNyblZlcmt1R2l0dThNaXRRY2NjYUZweWJKZjBkamFjK0VheGxiSzUr?=
 =?utf-8?B?ZXRML3UzS2NURTd6Skg5U2NKUDl6b2MvbE1aYjcxWitDV3dneFJEUklHYUEv?=
 =?utf-8?B?aENzODAyTDduZ3B1TFFOblBxc2lwUWxocnpRbjBIM2l1ZVVIamJHajY5ZGpT?=
 =?utf-8?B?NDlqWFdKRkU5UFhObDdXRldEQ2FnK1dlSWNZNjQrZ3YxVjllTFJNZjhVdVZX?=
 =?utf-8?Q?Im9Q=3D?=
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-Network-Message-Id: a019d729-429f-4868-fd8c-08dc5d8306c9
X-MS-Exchange-CrossTenant-AuthSource: PAXPR04MB9642.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Apr 2024 19:34:11.7238
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: zgEOQmaRJINeTMfGUR/2iPj+zmuwPe5WSJzQFJxsFEFsdHjaE1WkdYS3whxIjqRaQCAmk/5kAenbEJruxtAOiQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA2PR04MB10279

Instead of relying on the vendor specific implementations to send the
PME_Turn_Off message, let's introduce a generic way of sending the message
using the MSG TLP.

This is achieved by reserving a region for MSG TLP of size
'pci->region_align', at the end of the first IORESOURCE_MEM window of the
host bridge. And then sending the PME_Turn_Off message during system
suspend with the help of iATU.

The reserve space at end is a little bit better than alloc_resource()
because the below reasons.
- alloc_resource() will allocate space at begin of IORESOURCE_MEM window.
There will be a hole when first Endpoint Device (EP) try to alloc a bigger
space then 'region_align' size.
- Keep EP device's IORESOURCE_MEM space unchange with/without this patch.

It should be noted that this generic implementation is optional for the
glue drivers and can be overridden by a custom 'pme_turn_off' callback.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 94 ++++++++++++++++++++++-
 drivers/pci/controller/dwc/pcie-designware.h      |  3 +
 2 files changed, 93 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 3a9cb4be22ab2..5001cdf220123 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -398,6 +398,31 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp)
 	return 0;
 }
 
+static void dw_pcie_host_request_msg_tlp_res(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct resource_entry *win;
+	struct resource *res;
+
+	win = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM);
+	if (win) {
+		res = devm_kzalloc(pci->dev, sizeof(*res), GFP_KERNEL);
+		if (!res)
+			return;
+
+		/* Reserve last region_align block as message TLP space */
+		res->start = win->res->end - pci->region_align + 1;
+		res->end = win->res->end;
+		res->name = "msg";
+		res->flags = win->res->flags | IORESOURCE_BUSY;
+
+		if (!devm_request_resource(pci->dev, win->res, res))
+			pp->msg_res = res;
+		else
+			devm_kfree(pci->dev, res);
+	}
+}
+
 int dw_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -484,6 +509,16 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 
 	dw_pcie_iatu_detect(pci);
 
+	/*
+	 * Allocate the resource for MSG TLP before programming the iATU outbound window in
+	 * dw_pcie_setup_rc(). Since the allocation depends on the value of 'region_align', this has
+	 * to be done after dw_pcie_iatu_detect().
+	 *
+	 * Glue driver need set use_atu_msg before dw_pcie_host_init() if want MSG TLP feature.
+	 */
+	if (pp->use_atu_msg)
+		dw_pcie_host_request_msg_tlp_res(pp);
+
 	ret = dw_pcie_edma_detect(pci);
 	if (ret)
 		goto err_free_msi;
@@ -541,6 +576,11 @@ void dw_pcie_host_deinit(struct dw_pcie_rp *pp)
 
 	dw_pcie_edma_remove(pci);
 
+	if (pp->msg_res) {
+		release_resource(pp->msg_res);
+		devm_kfree(pci->dev, pp->msg_res);
+	}
+
 	if (pp->has_msi_ctrl)
 		dw_pcie_free_msi(pp);
 
@@ -702,6 +742,10 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp)
 		atu.pci_addr = entry->res->start - entry->offset;
 		atu.size = resource_size(entry->res);
 
+		/* MSG TLB window resource reserve at one of end of IORESOURCE_MEM resource */
+		if (pp->msg_res && pp->msg_res->parent == entry->res)
+			atu.size -= resource_size(pp->msg_res);
+
 		ret = dw_pcie_prog_outbound_atu(pci, &atu);
 		if (ret) {
 			dev_err(pci->dev, "Failed to set MEM range %pr\n",
@@ -733,6 +777,8 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp)
 		dev_warn(pci->dev, "Ranges exceed outbound iATU size (%d)\n",
 			 pci->num_ob_windows);
 
+	pp->msg_atu_index = i;
+
 	i = 0;
 	resource_list_for_each_entry(entry, &pp->bridge->dma_ranges) {
 		if (resource_type(entry->res) != IORESOURCE_MEM)
@@ -838,11 +884,48 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
 }
 EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);
 
+/* Using message outbound ATU to send out PME_Turn_Off message for dwc PCIe controller */
+static int dw_pcie_pme_turn_off(struct dw_pcie *pci)
+{
+	struct dw_pcie_ob_atu_cfg atu = { 0 };
+	void __iomem *mem;
+	int ret;
+
+	if (pci->num_ob_windows <= pci->pp.msg_atu_index)
+		return -EINVAL;
+
+	if (!pci->pp.msg_res)
+		return -EINVAL;
+
+	atu.code = PCIE_MSG_CODE_PME_TURN_OFF;
+	atu.routing = PCIE_MSG_TYPE_R_BC;
+	atu.type = PCIE_ATU_TYPE_MSG;
+	atu.size = resource_size(pci->pp.msg_res);
+	atu.index = pci->pp.msg_atu_index;
+
+	atu.cpu_addr = pci->pp.msg_res->start;
+
+	ret = dw_pcie_prog_outbound_atu(pci, &atu);
+	if (ret)
+		return ret;
+
+	mem = ioremap(atu.cpu_addr, pci->region_align);
+	if (!mem)
+		return -ENOMEM;
+
+	/* A dummy write is converted to a Msg TLP */
+	writel(0, mem);
+
+	iounmap(mem);
+
+	return 0;
+}
+
 int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 {
 	u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
 	u32 val;
-	int ret;
+	int ret = 0;
 
 	/*
 	 * If L1SS is supported, then do not put the link into L2 as some
@@ -854,10 +937,13 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 	if (dw_pcie_get_ltssm(pci) <= DW_PCIE_LTSSM_DETECT_ACT)
 		return 0;
 
-	if (!pci->pp.ops->pme_turn_off)
-		return 0;
+	if (pci->pp.ops->pme_turn_off)
+		pci->pp.ops->pme_turn_off(&pci->pp);
+	else
+		ret = dw_pcie_pme_turn_off(pci);
 
-	pci->pp.ops->pme_turn_off(&pci->pp);
+	if (ret)
+		return ret;
 
 	ret = read_poll_timeout(dw_pcie_get_ltssm, val, val == DW_PCIE_LTSSM_L2_IDLE,
 				PCIE_PME_TO_L2_TIMEOUT_US/10,
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 703b50bc5e0f1..dca5de4c6e877 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -341,6 +341,9 @@ struct dw_pcie_rp {
 	struct pci_host_bridge  *bridge;
 	raw_spinlock_t		lock;
 	DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
+	bool			use_atu_msg;
+	int			msg_atu_index;
+	struct resource		*msg_res;
 };
 
 struct dw_pcie_ep_ops {

-- 
2.34.1