[PATCH v11 09/13] PCI: dwc: Add support for triggering legacy IRQs

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Add support for triggering legacy IRQs by using outbound iATU.
Outbound iATU is utilized to send assert and de-assert INTx TLPs.
The message is generated based on the payloadless Msg TLP with type
0x14, where 0x4 is the routing code implying the terminated at
Receiver message. The message code is specified as b1000xx for
the INTx assertion and b1001xx for the INTx de-assertion.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
 .../pci/controller/dwc/pcie-designware-ep.c   | 66 ++++++++++++--
 drivers/pci/controller/dwc/pcie-designware.c  | 88 +++++++++++++------
 drivers/pci/controller/dwc/pcie-designware.h  | 11 ++-
 3 files changed, 126 insertions(+), 39 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 95efe14f1036..73b3844e8a09 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -6,6 +6,7 @@
  * Author: Kishon Vijay Abraham I <kishon@xxxxxx>
  */
 
+#include <linux/delay.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 
@@ -182,8 +183,8 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
 	return 0;
 }
 
-static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, u8 func_no,
-				   phys_addr_t phys_addr,
+static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
+				   u8 code, u8 routing, phys_addr_t phys_addr,
 				   u64 pci_addr, size_t size)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
@@ -196,8 +197,9 @@ static int dw_pcie_ep_outbound_atu(struct dw_pcie_ep *ep, u8 func_no,
 		return -EINVAL;
 	}
 
-	ret = dw_pcie_prog_ep_outbound_atu(pci, func_no, free_win, PCIE_ATU_TYPE_MEM,
-					   phys_addr, pci_addr, size);
+	ret = dw_pcie_prog_ep_outbound_atu(pci, func_no, free_win, type,
+					   code, routing, phys_addr, pci_addr,
+					   size);
 	if (ret)
 		return ret;
 
@@ -306,7 +308,8 @@ static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	struct dw_pcie_ep *ep = epc_get_drvdata(epc);
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 
-	ret = dw_pcie_ep_outbound_atu(ep, func_no, addr, pci_addr, size);
+	ret = dw_pcie_ep_outbound_atu(ep, func_no, PCIE_ATU_TYPE_MEM, 0, 0,
+				      addr, pci_addr, size);
 	if (ret) {
 		dev_err(pci->dev, "Failed to enable address\n");
 		return ret;
@@ -479,14 +482,46 @@ static const struct pci_epc_ops epc_ops = {
 	.get_features		= dw_pcie_ep_get_features,
 };
 
+static int dw_pcie_ep_send_msg(struct dw_pcie_ep *ep, u8 func_no, u8 code,
+			       u8 routing)
+{
+	struct pci_epc *epc = ep->epc;
+	int ret;
+
+	ret = dw_pcie_ep_outbound_atu(ep, func_no, PCIE_ATU_TYPE_MSG, code,
+				      routing, ep->intx_mem_phys, 0,
+				      epc->mem->window.page_size);
+	if (ret)
+		return ret;
+	writel(0, ep->intx_mem);
+	dw_pcie_ep_unmap_addr(epc, func_no, 0, ep->intx_mem_phys);
+
+	return 0;
+}
+
+static int __dw_pcie_ep_raise_legacy_irq(struct dw_pcie_ep *ep, u8 func_no,
+					 int intx)
+{
+	int ret;
+
+	ret = dw_pcie_ep_send_msg(ep, func_no, PCIE_MSG_ASSERT_INTA + intx, 0x04);
+	if (ret)
+		return ret;
+	usleep_range(1000, 2000);
+	return dw_pcie_ep_send_msg(ep, func_no, PCIE_MSG_DEASSERT_INTA + intx, 0x04);
+}
+
 int dw_pcie_ep_raise_legacy_irq(struct dw_pcie_ep *ep, u8 func_no)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
 	struct device *dev = pci->dev;
 
-	dev_err(dev, "EP cannot trigger legacy IRQs\n");
+	if (!ep->intx_mem) {
+		dev_err(dev, "EP cannot trigger legacy IRQs\n");
+		return -EINVAL;
+	}
 
-	return -EINVAL;
+	return __dw_pcie_ep_raise_legacy_irq(ep, func_no, 0);
 }
 EXPORT_SYMBOL_GPL(dw_pcie_ep_raise_legacy_irq);
 
@@ -617,6 +652,10 @@ void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
 
 	dw_pcie_edma_remove(pci);
 
+	if (ep->intx_mem)
+		pci_epc_mem_free_addr(epc, ep->intx_mem_phys, ep->intx_mem,
+				      epc->mem->window.page_size);
+
 	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
 			      epc->mem->window.page_size);
 
@@ -789,9 +828,14 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 		goto err_exit_epc_mem;
 	}
 
+	ep->intx_mem = pci_epc_mem_alloc_addr(epc, &ep->intx_mem_phys,
+					      epc->mem->window.page_size);
+	if (!ep->intx_mem)
+		dev_warn(dev, "Failed to reserve memory for INTx\n");
+
 	ret = dw_pcie_edma_detect(pci);
 	if (ret)
-		goto err_free_epc_mem;
+		goto err_free_epc_mem_intx;
 
 	if (ep->ops->get_features) {
 		epc_features = ep->ops->get_features(ep);
@@ -808,7 +852,11 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 err_remove_edma:
 	dw_pcie_edma_remove(pci);
 
-err_free_epc_mem:
+err_free_epc_mem_intx:
+	if (ep->intx_mem)
+		pci_epc_mem_free_addr(epc, ep->intx_mem_phys, ep->intx_mem,
+				      epc->mem->window.page_size);
+
 	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
 			      epc->mem->window.page_size);
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 47860da5738e..364926832126 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -23,6 +23,17 @@
 #include "../../pci.h"
 #include "pcie-designware.h"
 
+struct dw_pcie_outbound_atu {
+	u64 cpu_addr;
+	u64 pci_addr;
+	u64 size;
+	int index;
+	int type;
+	u8 func_no;
+	u8 code;
+	u8 routing;
+};
+
 static const char * const dw_pcie_app_clks[DW_PCIE_NUM_APP_CLKS] = {
 	[DW_PCIE_DBI_CLK] = "dbi",
 	[DW_PCIE_MSTR_CLK] = "mstr",
@@ -464,56 +475,58 @@ static inline u32 dw_pcie_enable_ecrc(u32 val)
 	return val | PCIE_ATU_TD;
 }
 
-static int __dw_pcie_prog_outbound_atu(struct dw_pcie *pci, u8 func_no,
-				       int index, int type, u64 cpu_addr,
-				       u64 pci_addr, u64 size)
+static int __dw_pcie_prog_outbound_atu(struct dw_pcie *pci,
+				       struct dw_pcie_outbound_atu *atu)
 {
 	u32 retries, val;
 	u64 limit_addr;
 
 	if (pci->ops && pci->ops->cpu_addr_fixup)
-		cpu_addr = pci->ops->cpu_addr_fixup(pci, cpu_addr);
+		atu->cpu_addr = pci->ops->cpu_addr_fixup(pci, atu->cpu_addr);
 
-	limit_addr = cpu_addr + size - 1;
+	limit_addr = atu->cpu_addr + atu->size - 1;
 
-	if ((limit_addr & ~pci->region_limit) != (cpu_addr & ~pci->region_limit) ||
-	    !IS_ALIGNED(cpu_addr, pci->region_align) ||
-	    !IS_ALIGNED(pci_addr, pci->region_align) || !size) {
+	if ((limit_addr & ~pci->region_limit) != (atu->cpu_addr & ~pci->region_limit) ||
+	    !IS_ALIGNED(atu->cpu_addr, pci->region_align) ||
+	    !IS_ALIGNED(atu->pci_addr, pci->region_align) || !atu->size) {
 		return -EINVAL;
 	}
 
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_LOWER_BASE,
-			      lower_32_bits(cpu_addr));
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_UPPER_BASE,
-			      upper_32_bits(cpu_addr));
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_LOWER_BASE,
+			      lower_32_bits(atu->cpu_addr));
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_UPPER_BASE,
+			      upper_32_bits(atu->cpu_addr));
 
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_LIMIT,
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_LIMIT,
 			      lower_32_bits(limit_addr));
 	if (dw_pcie_ver_is_ge(pci, 460A))
-		dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_UPPER_LIMIT,
+		dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_UPPER_LIMIT,
 				      upper_32_bits(limit_addr));
 
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_LOWER_TARGET,
-			      lower_32_bits(pci_addr));
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_UPPER_TARGET,
-			      upper_32_bits(pci_addr));
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_LOWER_TARGET,
+			      lower_32_bits(atu->pci_addr));
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_UPPER_TARGET,
+			      upper_32_bits(atu->pci_addr));
 
-	val = type | PCIE_ATU_FUNC_NUM(func_no);
-	if (upper_32_bits(limit_addr) > upper_32_bits(cpu_addr) &&
+	val = atu->type | atu->routing | PCIE_ATU_FUNC_NUM(atu->func_no);
+	if (upper_32_bits(limit_addr) > upper_32_bits(atu->cpu_addr) &&
 	    dw_pcie_ver_is_ge(pci, 460A))
 		val |= PCIE_ATU_INCREASE_REGION_SIZE;
 	if (dw_pcie_ver_is(pci, 490A))
 		val = dw_pcie_enable_ecrc(val);
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_REGION_CTRL1, val);
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL1, val);
 
-	dw_pcie_writel_atu_ob(pci, index, PCIE_ATU_REGION_CTRL2, PCIE_ATU_ENABLE);
+	val = PCIE_ATU_ENABLE;
+	if (atu->type == PCIE_ATU_TYPE_MSG)
+		val |= PCIE_ATU_INHIBIT_PAYLOAD | PCIE_ATU_HEADER_SUB_ENABLE | atu->code;
+	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL2, val);
 
 	/*
 	 * Make sure ATU enable takes effect before any subsequent config
 	 * and I/O accesses.
 	 */
 	for (retries = 0; retries < LINK_WAIT_MAX_IATU_RETRIES; retries++) {
-		val = dw_pcie_readl_atu_ob(pci, index, PCIE_ATU_REGION_CTRL2);
+		val = dw_pcie_readl_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL2);
 		if (val & PCIE_ATU_ENABLE)
 			return 0;
 
@@ -528,16 +541,33 @@ static int __dw_pcie_prog_outbound_atu(struct dw_pcie *pci, u8 func_no,
 int dw_pcie_prog_outbound_atu(struct dw_pcie *pci, int index, int type,
 			      u64 cpu_addr, u64 pci_addr, u64 size)
 {
-	return __dw_pcie_prog_outbound_atu(pci, 0, index, type,
-					   cpu_addr, pci_addr, size);
+	struct dw_pcie_outbound_atu atu;
+
+	memset(&atu, 0, sizeof(atu));
+	atu.index = index;
+	atu.type = type;
+	atu.cpu_addr = cpu_addr;
+	atu.pci_addr = pci_addr;
+	atu.size = size;
+	return __dw_pcie_prog_outbound_atu(pci, &atu);
 }
 
 int dw_pcie_prog_ep_outbound_atu(struct dw_pcie *pci, u8 func_no, int index,
-				 int type, u64 cpu_addr, u64 pci_addr,
-				 u64 size)
+				 int type, u8 code, u8 routing, u64 cpu_addr,
+				 u64 pci_addr, u64 size)
 {
-	return __dw_pcie_prog_outbound_atu(pci, func_no, index, type,
-					   cpu_addr, pci_addr, size);
+	struct dw_pcie_outbound_atu atu;
+
+	memset(&atu, 0, sizeof(atu));
+	atu.func_no = func_no;
+	atu.index = index;
+	atu.type = type;
+	atu.code = code;
+	atu.routing = routing;
+	atu.cpu_addr = cpu_addr;
+	atu.pci_addr = pci_addr;
+	atu.size = size;
+	return __dw_pcie_prog_outbound_atu(pci, &atu);
 }
 
 static inline u32 dw_pcie_readl_atu_ib(struct dw_pcie *pci, u32 index, u32 reg)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 36f3e2c818fe..3dbadb8043ab 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -147,11 +147,14 @@
 #define PCIE_ATU_TYPE_IO		0x2
 #define PCIE_ATU_TYPE_CFG0		0x4
 #define PCIE_ATU_TYPE_CFG1		0x5
+#define PCIE_ATU_TYPE_MSG		0x10
 #define PCIE_ATU_TD			BIT(8)
 #define PCIE_ATU_FUNC_NUM(pf)           ((pf) << 20)
 #define PCIE_ATU_REGION_CTRL2		0x004
 #define PCIE_ATU_ENABLE			BIT(31)
 #define PCIE_ATU_BAR_MODE_ENABLE	BIT(30)
+#define PCIE_ATU_INHIBIT_PAYLOAD	BIT(22)
+#define PCIE_ATU_HEADER_SUB_ENABLE	BIT(21)
 #define PCIE_ATU_FUNC_NUM_MATCH_EN      BIT(19)
 #define PCIE_ATU_LOWER_BASE		0x008
 #define PCIE_ATU_UPPER_BASE		0x00C
@@ -244,6 +247,9 @@
 /* Default eDMA LLP memory size */
 #define DMA_LLP_MEM_SIZE		PAGE_SIZE
 
+#define PCIE_MSG_ASSERT_INTA		0x20
+#define PCIE_MSG_DEASSERT_INTA		0x24
+
 struct dw_pcie;
 struct dw_pcie_rp;
 struct dw_pcie_ep;
@@ -352,6 +358,8 @@ struct dw_pcie_ep {
 	unsigned long		*ob_window_map;
 	void __iomem		*msi_mem;
 	phys_addr_t		msi_mem_phys;
+	void __iomem		*intx_mem;
+	phys_addr_t		intx_mem_phys;
 	struct pci_epf_bar	*epf_bar[PCI_STD_NUM_BARS];
 };
 
@@ -420,7 +428,8 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci);
 int dw_pcie_prog_outbound_atu(struct dw_pcie *pci, int index, int type,
 			      u64 cpu_addr, u64 pci_addr, u64 size);
 int dw_pcie_prog_ep_outbound_atu(struct dw_pcie *pci, u8 func_no, int index,
-				 int type, u64 cpu_addr, u64 pci_addr, u64 size);
+				 int type, u8 code, u8 routing, u64 cpu_addr,
+				 u64 pci_addr, u64 size);
 int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type,
 			     u64 cpu_addr, u64 pci_addr, u64 size);
 int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index,
-- 
2.25.1




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