On Wednesday 17 December 2014 04:04 PM, Gabriel FERNANDEZ wrote:
sti pcie is built around a Synopsis Designware PCIe IP.
Signed-off-by: Fabrice Gasnier <fabrice.gasn...@st.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernan...@linaro.org>
---
drivers/pci/host/Kconfig | 5 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pci-st.c | 713 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 719 insertions(+)
create mode 100644 drivers/pci/host/pci-st.c
[...]
+static int st_pcie_abort_handler(unsigned long addr, unsigned int fsr,
+ struct pt_regs *regs)
+{
+ return 0;
+}
+
You should have modification here to populate registers having cfg read
values by 0xFFFFFFFF.
I would suggest to have a look here:
drivers/pci/host/pci-keystone.c:keystone_pcie_fault
+/*
+ * The PCI express core IP expects the following arrangement on it's address
+ * bus (slv_haddr) when driving config cycles.
+ * bus_number [31:24]
+ * dev_number [23:19]
+ * func_number [18:16]
+ * unused [15:12]
+ * ext_reg_number [11:8]
+ * reg_number [7:2]
+ *
+ * Bits [15:12] are unused.
+ *
+ * In the glue logic there is a 64K region of address space that can be
+ * written/read to generate config cycles. The base address of this is
+ * controlled by CFG_BASE_ADDRESS. There are 8 16 bit registers called
+ * FUNC0_BDF_NUM to FUNC8_BDF_NUM. These split the bottom half of the 64K
+ * window into 8 regions at 4K boundaries. These control the bus,device and
+ * function number you are trying to talk to.
+ *
+ * The decision on whether to generate a type 0 or type 1 access is controlled
+ * by bits 15:12 of the address you write to. If they are zero, then a type 0
+ * is generated, if anything else it will be a type 1. Thus the bottom 4K
+ * region controlled by FUNC0_BDF_NUM can only generate type 0, all the others
+ * can only generate type 1.
+ *
+ * We only use FUNC0_BDF_NUM and FUNC1_BDF_NUM. Which one you use is selected
+ * by bit 12 of the address you write to. The selected register is then used
+ * for the top 16 bits of the slv_haddr to form the bus/dev/func, bit 15:12 are
+ * wired to zero, and bits 11:2 form the address of the register you want to
+ * read in config space.
+ *
+ * We always write FUNC0_BDF_NUM as a 32 bit write. So if we want type 1
+ * accesses we have to shift by 16 so in effect we are writing to FUNC1_BDF_NUM
+ */
+static inline u32 bdf_num(int bus, int devfn, int is_root_bus)
+{
+ return ((bus << 8) | devfn) << (is_root_bus ? 0 : 16);
+}
+
+static inline unsigned config_addr(int where, int is_root_bus)
+{
+ return (where & ~3) | (!is_root_bus << 12);
+}
+
+static int st_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+ unsigned int devfn, int where, int size,
+ u32 *val)
+{
+ u32 data;
+ u32 bdf;
+ struct st_pcie *pcie = to_st_pcie(pp);
+ int is_root_bus = pci_is_root_bus(bus);
+ int retry_count = 0;
+ int ret;
+ void __iomem *addr;
+
+ /*
+ * Prerequisite
+ * PCI express devices will respond to all config type 0 cycles, since
+ * they are point to point links. Thus to avoid probing for multiple
+ * devices on the root, dw-pcie already check for us if it is on the
+ * root bus / other slots. Also, dw-pcie checks for the link being up
+ * as we will hang if we issue a config request and the link is down.
+ * A switch will reject requests for slots it knows do not exist.
+ */
+ bdf = bdf_num(bus->number, devfn, is_root_bus);
+ addr = pcie->config_area + config_addr(where,
+ bus->parent->number == pp->root_bus_nr);
+retry:
+ /* Set the config packet devfn */
+ writel_relaxed(bdf, pp->dbi_base + FUNC0_BDF_NUM);
+ readl_relaxed(pp->dbi_base + FUNC0_BDF_NUM);
+
+ ret = dw_pcie_cfg_read(addr, where, size, &data);
+
+ /*
+ * This is intended to help with when we are probing the bus. The
+ * problem is that the wrapper logic doesn't have any way to
+ * interrogate if the configuration request failed or not.
+ * On the ARM we actually get a real bus error.
+ *
+ * Unfortunately this means it is impossible to tell the difference
+ * between when a device doesn't exist (the switch will return a UR
+ * completion) or the device does exist but isn't yet ready to accept
+ * configuration requests (the device will return a CRS completion)
+ *
+ * The result of this is that we will miss devices when probing.
+ *
+ * So if we are trying to read the dev/vendor id on devfn 0 and we
+ * appear to get zero back, then we retry the request. We know that
+ * zero can never be a valid device/vendor id. The specification says
+ * we must retry for up to a second before we decide the device is
Not sure if retry has to be part of software. This might already be done
by hardware.
+ * dead. If we are still dead then we assume there is nothing there and
+ * return ~0
+ *
+ * The downside of this is that we incur a delay of 1s for every pci
+ * express link that doesn't have a device connected.
+ */
+ if (((where & ~3) == 0) && devfn == 0 && (data == 0 || data == ~0)) {
+ if (retry_count++ < 1000) {
+ mdelay(1);
+ goto retry;
+ } else {
+ *val = ~0;
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ }
+ }
Have you found a situation with any of the card when your retry_count >
0 and < 1000 at this point. If not then, I think modifying abort
handler will solve your issue.
+
+ *val = data;
+ return ret;
+}
+
~Pratyush
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