Dear all,
On Wed, 16 Mar 2016 18:36:22 +0800 Jisheng Zhang wrote:
> dw_pcie_setup_rc(), as its name indicates, setups the RC. But current
> dw_pcie_host_init() also contains some necessary rc setup code.
>
> Another reason: the host may lost power during suspend to ram, the RC
> need to be re-setup after resume. The rc can't be correctly resumed
> without the rc setup code in dw_pcie_host_init().
>
> So this patch moves the code to dw_pcie_setup_rc() to address the above
> two issues. After this patch, each pcie designware driver users could
> call dw_pcie_setup_rc() to re-setup rc when resume back.
Some background of this patch: we want to add suspend/resume support to BG4CT
pcie hosts. The host will lost power when suspend to ram, and reset when resume
back. So I must re-setup the rc by dw_pcie_setup_rc().
Tested on Marvell BG4CT platforms.
Two issues need your help:
1. duplicate PCI_BASE_ADDRESS_0 programming. we first write 4 to
PCI_BASE_ADDRESS_0 in dw_pcie_setup_rc(), then write 0 to it again in
dw_pcie_host_init(). Is there any reason to do so? could we remove
the latter PCI_BASE_ADDRESS_0 programming?
2. could we move the PORT_LOGIC_SPEED_CHANGE bit setting early, I.E with
something as below:
Thanks,
Jisheng
diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 6474f80..b824f6f 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -737,6 +737,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
/* set link width speed control register */
dw_pcie_readl_rc(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, &val);
val &= ~PORT_LOGIC_LINK_WIDTH_MASK;
+ val |= PORT_LOGIC_SPEED_CHANGE;
switch (pp->lanes) {
case 1:
val |= PORT_LOGIC_LINK_WIDTH_1_LANES;
@@ -796,10 +797,6 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
/* program correct class for RC */
dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI);
-
- dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val);
- val |= PORT_LOGIC_SPEED_CHANGE;
- dw_pcie_wr_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, val);
}
MODULE_AUTHOR("Jingoo Han <jg1.han@xxxxxxxxxxx>");
>
> Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
> ---
> drivers/pci/host/pcie-designware.c | 38 +++++++++++++++++++-------------------
> 1 file changed, 19 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index a4cccd3..6474f80 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -544,25 +544,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
> if (pp->ops->host_init)
> pp->ops->host_init(pp);
>
> - /*
> - * If the platform provides ->rd_other_conf, it means the platform
> - * uses its own address translation component rather than ATU, so
> - * we should not program the ATU here.
> - */
> - if (!pp->ops->rd_other_conf)
> - dw_pcie_prog_outbound_atu(pp, PCIE_ATU_REGION_INDEX1,
> - PCIE_ATU_TYPE_MEM, pp->mem_base,
> - pp->mem_bus_addr, pp->mem_size);
> -
> - dw_pcie_wr_own_conf(pp, PCI_BASE_ADDRESS_0, 4, 0);
> -
> - /* program correct class for RC */
> - dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI);
> -
> - dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val);
> - val |= PORT_LOGIC_SPEED_CHANGE;
> - dw_pcie_wr_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, val);
> -
> pp->root_bus_nr = pp->busn->start;
> if (IS_ENABLED(CONFIG_PCI_MSI)) {
> bus = pci_scan_root_bus_msi(pp->dev, pp->root_bus_nr,
> @@ -800,6 +781,25 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
> val |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
> PCI_COMMAND_MASTER | PCI_COMMAND_SERR;
> dw_pcie_writel_rc(pp, val, PCI_COMMAND);
> +
> + /*
> + * If the platform provides ->rd_other_conf, it means the platform
> + * uses its own address translation component rather than ATU, so
> + * we should not program the ATU here.
> + */
> + if (!pp->ops->rd_other_conf)
> + dw_pcie_prog_outbound_atu(pp, PCIE_ATU_REGION_INDEX1,
> + PCIE_ATU_TYPE_MEM, pp->mem_base,
> + pp->mem_bus_addr, pp->mem_size);
> +
> + dw_pcie_wr_own_conf(pp, PCI_BASE_ADDRESS_0, 4, 0);
> +
> + /* program correct class for RC */
> + dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI);
> +
> + dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val);
> + val |= PORT_LOGIC_SPEED_CHANGE;
> + dw_pcie_wr_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, val);
> }
>
> MODULE_AUTHOR("Jingoo Han <jg1.han@xxxxxxxxxxx>");
--
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