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PCI: rockchip-host: Wait 100ms after reset before starting configuration

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PCIe r6.0, sec 6.6.1, states that the host should wait for at least 100
msec from the end of a conventional reset (PERST# is de-asserted) before
sending a configuration request to ensure that the device is able to
respond with a "Request Retry Status" completion.

Add the PCIE_T_RRS_READY_MS macro to define this wait time and modify
rockchip_pcie_host_init_port() to add this 100ms sleep after deasserting
PERST# using the ep_gpio GPIO.

Link: https://lore.kernel.org/linux-pci/20240413004120.1099089-3-dlemoal@kernel.org
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
This commit is contained in:
Damien Le Moal 2024-04-13 09:41:20 +09:00 committed by Bjorn Helgaas
parent c47f90be4c
commit 70a7bfb1e5
2 changed files with 9 additions and 0 deletions
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2
drivers/pci/controller/pcie-rockchip-host.c
View File

@ -325,6 +325,8 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
msleep(PCIE_T_PVPERL_MS);
gpiod_set_value_cansleep(rockchip->ep_gpio, 1);
msleep(PCIE_T_RRS_READY_MS);
/* 500ms timeout value should be enough for Gen1/2 training */
err = readl_poll_timeout(rockchip->apb_base + PCIE_CLIENT_BASIC_STATUS1,
status, PCIE_LINK_UP(status), 20,

7
drivers/pci/pci.h
View File

@ -16,6 +16,13 @@
/* Power stable to PERST# inactive from PCIe card Electromechanical Spec */
#define PCIE_T_PVPERL_MS 100
/*
* End of conventional reset (PERST# de-asserted) to first configuration
* request (device able to respond with a "Request Retry Status" completion),
* from PCIe r6.0, sec 6.6.1.
*/
#define PCIE_T_RRS_READY_MS 100
/*
* PCIe r6.0, sec 5.3.3.2.1 <PME Synchronization>
* Recommends 1ms to 10ms timeout to check L2 ready.