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arm: a37xx: pci: Handle propagation of CRSSVE bit from PCIe Root Port

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Now that PCI Bridge (PCIe Root Port) for Aardvark is emulated in U-Boot,
add support for handling and propagation of CRSSVE bit.

When CRSSVE bit is unset (default), driver has to reissue config
read/write request on CRS response.

CRSSVE bit is supported only when CRSVIS bit is provided in read-only
Root Capabilities register. So manually inject this CRSVIS bit into read
response for that register.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Pali Rohár 2021-09-26 00:54:44 +02:00 committed by Stefan Roese
parent 95e101e86a
commit 1d7ad68559
2 changed files with 26 additions and 4 deletions
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26
drivers/pci/pci-aardvark.c
View file

@ -41,6 +41,7 @@
#define PCIE_CORE_CMD_MEM_IO_REQ_EN BIT(2)
#define PCIE_CORE_DEV_REV_REG 0x8
#define PCIE_CORE_EXP_ROM_BAR_REG 0x30
#define PCIE_CORE_PCIEXP_CAP_OFF 0xc0
#define PCIE_CORE_DEV_CTRL_STATS_REG 0xc8
#define PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE (0 << 4)
#define PCIE_CORE_DEV_CTRL_STATS_SNOOP_DISABLE (0 << 11)
@ -201,6 +202,7 @@ struct pcie_advk {
struct udevice *dev;
struct gpio_desc reset_gpio;
u32 cfgcache[0x34 - 0x10];
bool cfgcrssve;
};
static inline void advk_writel(struct pcie_advk *pcie, uint val, uint reg)
@ -413,6 +415,18 @@ static int pcie_advk_read_config(const struct udevice *bus, pci_dev_t bdf,
data |= PCI_HEADER_TYPE_BRIDGE << 16;
}
if ((offset & ~3) == PCIE_CORE_PCIEXP_CAP_OFF + PCI_EXP_RTCTL) {
/* CRSSVE bit is stored only in cache */
if (pcie->cfgcrssve)
data |= PCI_EXP_RTCTL_CRSSVE;
}
if ((offset & ~3) == PCIE_CORE_PCIEXP_CAP_OFF +
(PCI_EXP_RTCAP & ~3)) {
/* CRS is emulated below, so set CRSVIS capability */
data |= PCI_EXP_RTCAP_CRSVIS << 16;
}
*valuep = pci_conv_32_to_size(data, offset, size);
return 0;
@ -423,13 +437,14 @@ static int pcie_advk_read_config(const struct udevice *bus, pci_dev_t bdf,
* OS is allowed only for 4-byte PCI_VENDOR_ID config read request and
* only when CRSSVE bit in Root Port PCIe device is enabled. In all
* other error PCIe Root Complex must return all-ones.
* Aardvark HW does not have Root Port PCIe device and U-Boot does not
* implement emulation of this device.
*
* U-Boot currently does not support handling of CRS return value for
* PCI_VENDOR_ID config read request and also does not set CRSSVE bit.
* Therefore disable returning CRS response for now.
* So it means that pcie->cfgcrssve is false. But the code is prepared
* for returning CRS, so that if U-Boot does support CRS in the future,
* it will work for Aardvark.
*/
allow_crs = false;
allow_crs = pcie->cfgcrssve;
if (advk_readl(pcie, PIO_START)) {
dev_err(pcie->dev,
@ -583,6 +598,9 @@ static int pcie_advk_write_config(struct udevice *bus, pci_dev_t bdf,
(offset == PCI_PRIMARY_BUS && size != PCI_SIZE_8))
pcie->sec_busno = (data >> 8) & 0xff;
if ((offset & ~3) == PCIE_CORE_PCIEXP_CAP_OFF + PCI_EXP_RTCTL)
pcie->cfgcrssve = data & PCI_EXP_RTCTL_CRSSVE;
return 0;
}

4
include/pci.h
View file

@ -495,6 +495,10 @@
#define PCI_EXP_LNKSTA_DLLLA 0x2000 /* Data Link Layer Link Active */
#define PCI_EXP_SLTCAP 20 /* Slot Capabilities */
#define PCI_EXP_SLTCAP_PSN 0xfff80000 /* Physical Slot Number */
#define PCI_EXP_RTCTL 28 /* Root Control */
#define PCI_EXP_RTCTL_CRSSVE 0x0010 /* CRS Software Visibility Enable */
#define PCI_EXP_RTCAP 30 /* Root Capabilities */
#define PCI_EXP_RTCAP_CRSVIS 0x0001 /* CRS Software Visibility capability */
#define PCI_EXP_DEVCAP2 36 /* Device Capabilities 2 */
#define PCI_EXP_DEVCAP2_ARI 0x00000020 /* ARI Forwarding Supported */
#define PCI_EXP_DEVCTL2 40 /* Device Control 2 */