PCI: cadence: Add EndPoint Controller driver for Cadence PCIe controller

This patch adds support to the Cadence PCIe controller in endpoint mode.

Since pieces of source code are shared with the host driver (Root
Complex mode), we create a new directory under drivers/pci dedicated to
the Cadence PCIe controller. The common code is placed into
drivers/pci/cadence/pcie-cadence.c and used by both the host and
endpoint controller drivers.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

1 files changed, 126 insertions, 0 deletions

diff --git a/drivers/pci/cadence/pcie-cadence.c b/drivers/pci/cadence/pcie-cadence.c
new file mode 100644
index 000000000000..138d113eb45d
--- /dev/null
+++ b/drivers/pci/cadence/pcie-cadence.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2017 Cadence
+// Cadence PCIe controller driver.
+// Author: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
+
+#include <linux/kernel.h>
+
+#include "pcie-cadence.h"
+
+void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 fn,
+				   u32 r, bool is_io,
+				   u64 cpu_addr, u64 pci_addr, size_t size)
+{
+	/*
+	 * roundup_pow_of_two() returns an unsigned long, which is not suited
+	 * for 64bit values.
+	 */
+	u64 sz = 1ULL << fls64(size - 1);
+	int nbits = ilog2(sz);
+	u32 addr0, addr1, desc0, desc1;
+
+	if (nbits < 8)
+		nbits = 8;
+
+	/* Set the PCI address */
+	addr0 = CDNS_PCIE_AT_OB_REGION_PCI_ADDR0_NBITS(nbits) |
+		(lower_32_bits(pci_addr) & GENMASK(31, 8));
+	addr1 = upper_32_bits(pci_addr);
+
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), addr0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), addr1);
+
+	/* Set the PCIe header descriptor */
+	if (is_io)
+		desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_IO;
+	else
+		desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_MEM;
+	desc1 = 0;
+
+	/*
+	 * Whatever Bit [23] is set or not inside DESC0 register of the outbound
+	 * PCIe descriptor, the PCI function number must be set into
+	 * Bits [26:24] of DESC0 anyway.
+	 *
+	 * In Root Complex mode, the function number is always 0 but in Endpoint
+	 * mode, the PCIe controller may support more than one function. This
+	 * function number needs to be set properly into the outbound PCIe
+	 * descriptor.
+	 *
+	 * Besides, setting Bit [23] is mandatory when in Root Complex mode:
+	 * then the driver must provide the bus, resp. device, number in
+	 * Bits [7:0] of DESC1, resp. Bits[31:27] of DESC0. Like the function
+	 * number, the device number is always 0 in Root Complex mode.
+	 *
+	 * However when in Endpoint mode, we can clear Bit [23] of DESC0, hence
+	 * the PCIe controller will use the captured values for the bus and
+	 * device numbers.
+	 */
+	if (pcie->is_rc) {
+		/* The device and function numbers are always 0. */
+		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
+			 CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
+		desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
+	} else {
+		/*
+		 * Use captured values for bus and device numbers but still
+		 * need to set the function number.
+		 */
+		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(fn);
+	}
+
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
+
+	/* Set the CPU address */
+	cpu_addr -= pcie->mem_res->start;
+	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(nbits) |
+		(lower_32_bits(cpu_addr) & GENMASK(31, 8));
+	addr1 = upper_32_bits(cpu_addr);
+
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
+}
+
+void cdns_pcie_set_outbound_region_for_normal_msg(struct cdns_pcie *pcie, u8 fn,
+						  u32 r, u64 cpu_addr)
+{
+	u32 addr0, addr1, desc0, desc1;
+
+	desc0 = CDNS_PCIE_AT_OB_REGION_DESC0_TYPE_NORMAL_MSG;
+	desc1 = 0;
+
+	/* See cdns_pcie_set_outbound_region() comments above. */
+	if (pcie->is_rc) {
+		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_HARDCODED_RID |
+			 CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(0);
+		desc1 |= CDNS_PCIE_AT_OB_REGION_DESC1_BUS(pcie->bus);
+	} else {
+		desc0 |= CDNS_PCIE_AT_OB_REGION_DESC0_DEVFN(fn);
+	}
+
+	/* Set the CPU address */
+	cpu_addr -= pcie->mem_res->start;
+	addr0 = CDNS_PCIE_AT_OB_REGION_CPU_ADDR0_NBITS(17) |
+		(lower_32_bits(cpu_addr) & GENMASK(31, 8));
+	addr1 = upper_32_bits(cpu_addr);
+
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), desc0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), desc1);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), addr0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), addr1);
+}
+
+void cdns_pcie_reset_outbound_region(struct cdns_pcie *pcie, u32 r)
+{
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR0(r), 0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_PCI_ADDR1(r), 0);
+
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC0(r), 0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_DESC1(r), 0);
+
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR0(r), 0);
+	cdns_pcie_writel(pcie, CDNS_PCIE_AT_OB_REGION_CPU_ADDR1(r), 0);
+}