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Date: Wed, 8 Jul 2020 15:00:07 +0530
From: Kishon Vijay Abraham I <kishon@...com>
To: Tom Joseph <tjoseph@...ence.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Rob Herring <robh+dt@...nel.org>,
Kishon Vijay Abraham I <kishon@...com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Arnd Bergmann <arnd@...db.de>
CC: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
<linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH v6 03/14] PCI: cadence: Convert all r/w accessors to perform only 32-bit accesses
Certain platforms like TI's J721E using Cadence PCIe IP can perform only
32-bit accesses for reading or writing to Cadence registers. Convert all
read and write accesses to 32-bit in Cadence PCIe driver in preparation
for adding PCIe support in TI's J721E SoC.
Also add spin lock to disable interrupts while modifying PCI_STATUS
register while raising legacy interrupt since PCI_STATUS is accessible
by both remote RC and EP and time between read and write should be
minimized.
Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
---
.../pci/controller/cadence/pcie-cadence-ep.c | 4 +
drivers/pci/controller/cadence/pcie-cadence.h | 76 ++++++++++++++-----
2 files changed, 62 insertions(+), 18 deletions(-)
diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c
index 4a829ccff7d0..c6eb2db94680 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -228,6 +228,7 @@ static void cdns_pcie_ep_assert_intx(struct cdns_pcie_ep *ep, u8 fn,
u8 intx, bool is_asserted)
{
struct cdns_pcie *pcie = &ep->pcie;
+ unsigned long flags;
u32 offset;
u16 status;
u8 msg_code;
@@ -252,11 +253,13 @@ static void cdns_pcie_ep_assert_intx(struct cdns_pcie_ep *ep, u8 fn,
msg_code = MSG_CODE_DEASSERT_INTA + intx;
}
+ spin_lock_irqsave(&ep->lock, flags);
status = cdns_pcie_ep_fn_readw(pcie, fn, PCI_STATUS);
if (((status & PCI_STATUS_INTERRUPT) != 0) ^ (ep->irq_pending != 0)) {
status ^= PCI_STATUS_INTERRUPT;
cdns_pcie_ep_fn_writew(pcie, fn, PCI_STATUS, status);
}
+ spin_unlock_irqrestore(&ep->lock, flags);
offset = CDNS_PCIE_NORMAL_MSG_ROUTING(MSG_ROUTING_LOCAL) |
CDNS_PCIE_NORMAL_MSG_CODE(msg_code) |
@@ -464,6 +467,7 @@ int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep)
ep->irq_pci_addr = CDNS_PCIE_EP_IRQ_PCI_ADDR_NONE;
/* Reserve region 0 for IRQs */
set_bit(0, &ep->ob_region_map);
+ spin_lock_init(&ep->lock);
return 0;
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index bc49c22e48a9..a45c11158f49 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -304,6 +304,9 @@ struct cdns_pcie_rc {
* @irq_pci_fn: the latest PCI function that has updated the mapping of
* the MSI/legacy IRQ dedicated outbound region.
* @irq_pending: bitmask of asserted legacy IRQs.
+ * @lock: spin lock to disable interrupts while modifying PCIe controller
+ * registers fields (RMW) accessible by both remote RC and EP to
+ * minimize time between read and write
*/
struct cdns_pcie_ep {
struct cdns_pcie pcie;
@@ -315,54 +318,94 @@ struct cdns_pcie_ep {
u64 irq_pci_addr;
u8 irq_pci_fn;
u8 irq_pending;
+ /* protect writing to PCI_STATUS while raising legacy interrupts */
+ spinlock_t lock;
};
/* Register access */
-static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8 value)
+static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
{
- writeb(value, pcie->reg_base + reg);
+ writel(value, pcie->reg_base + reg);
}
-static inline void cdns_pcie_writew(struct cdns_pcie *pcie, u32 reg, u16 value)
+static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
{
- writew(value, pcie->reg_base + reg);
+ return readl(pcie->reg_base + reg);
}
-static inline void cdns_pcie_writel(struct cdns_pcie *pcie, u32 reg, u32 value)
+static inline u32 cdns_pcie_read_sz(void __iomem *addr, int size)
{
- writel(value, pcie->reg_base + reg);
+ void __iomem *aligned_addr = PTR_ALIGN_DOWN(addr, 0x4);
+ unsigned int offset = (unsigned long)addr & 0x3;
+ u32 val = readl(aligned_addr);
+
+ if (!IS_ALIGNED((uintptr_t)addr, size)) {
+ WARN(1, "Address %p and size %d are not aligned\n", addr, size);
+ return 0;
+ }
+
+ if (size > 2)
+ return val;
+
+ return (val >> (8 * offset)) & ((1 << (size * 8)) - 1);
}
-static inline u32 cdns_pcie_readl(struct cdns_pcie *pcie, u32 reg)
+static inline void cdns_pcie_write_sz(void __iomem *addr, int size, u32 value)
{
- return readl(pcie->reg_base + reg);
+ void __iomem *aligned_addr = PTR_ALIGN_DOWN(addr, 0x4);
+ unsigned int offset = (unsigned long)addr & 0x3;
+ u32 mask;
+ u32 val;
+
+ if (!IS_ALIGNED((uintptr_t)addr, size)) {
+ WARN(1, "Address %p and size %d are not aligned\n", addr, size);
+ return;
+ }
+
+ if (size > 2) {
+ writel(value, addr);
+ return;
+ }
+
+ mask = ~(((1 << (size * 8)) - 1) << (offset * 8));
+ val = readl(aligned_addr) & mask;
+ val |= value << (offset * 8);
+ writel(val, aligned_addr);
}
/* Root Port register access */
static inline void cdns_pcie_rp_writeb(struct cdns_pcie *pcie,
u32 reg, u8 value)
{
- writeb(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
+ void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
+
+ cdns_pcie_write_sz(addr, 0x1, value);
}
static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
u32 reg, u16 value)
{
- writew(value, pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
+ void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
+
+ cdns_pcie_write_sz(addr, 0x2, value);
}
/* Endpoint Function register access */
static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
u32 reg, u8 value)
{
- writeb(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+ void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+ cdns_pcie_write_sz(addr, 0x1, value);
}
static inline void cdns_pcie_ep_fn_writew(struct cdns_pcie *pcie, u8 fn,
u32 reg, u16 value)
{
- writew(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+ void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+ cdns_pcie_write_sz(addr, 0x2, value);
}
static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
@@ -371,14 +414,11 @@ static inline void cdns_pcie_ep_fn_writel(struct cdns_pcie *pcie, u8 fn,
writel(value, pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
}
-static inline u8 cdns_pcie_ep_fn_readb(struct cdns_pcie *pcie, u8 fn, u32 reg)
-{
- return readb(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
-}
-
static inline u16 cdns_pcie_ep_fn_readw(struct cdns_pcie *pcie, u8 fn, u32 reg)
{
- return readw(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg);
+ void __iomem *addr = pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) + reg;
+
+ return cdns_pcie_read_sz(addr, 0x2);
}
static inline u32 cdns_pcie_ep_fn_readl(struct cdns_pcie *pcie, u8 fn, u32 reg)
--
2.17.1
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