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PCI: Add T_PERST_CLK_US macro

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The "Power Sequencing and Reset Signal Timings" table of the PCI
Express Card Electromechanical Specification, Revision 5.1, Section
2.9.2, indicates PERST# should be deasserted after minimum of 100us
once REFCLK is stable (symbol T_PERST-CLK).

Add a macro so that PCIe controller drivers can use it.

Link: https://lore.kernel.org/linux-pci/20240102-j7200-pcie-s2r-v7-5-a2f9156da6c3@bootlin.com
Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
[kwilczynski: commit log, update sleep interval macros code comments]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
This commit is contained in:
Thomas Richard 2024-06-19 12:15:13 +02:00 committed by Krzysztof Wilczyński
parent b8600b8791
commit 6aa9c09f1b
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1 changed files with 16 additions and 1 deletions
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17
drivers/pci/pci.h
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@ -13,9 +13,24 @@
#define PCIE_LINK_RETRAIN_TIMEOUT_MS 1000
/* Power stable to PERST# inactive from PCIe card Electromechanical Spec */
/*
* Power stable to PERST# inactive.
*
* See the "Power Sequencing and Reset Signal Timings" table of the PCI Express
* Card Electromechanical Specification, Revision 5.1, Section 2.9.2, Symbol
* "T_PVPERL".
*/
#define PCIE_T_PVPERL_MS 100
/*
* REFCLK stable before PERST# inactive.
*
* See the "Power Sequencing and Reset Signal Timings" table of the PCI Express
* Card Electromechanical Specification, Revision 5.1, Section 2.9.2, Symbol
* "T_PERST-CLK".
*/
#define PCIE_T_PERST_CLK_US 100
/*
* End of conventional reset (PERST# de-asserted) to first configuration
* request (device able to respond with a "Request Retry Status" completion),