63 lines
2.1 KiB
Diff
63 lines
2.1 KiB
Diff
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From 919357cfab0b8a07184b676b50c3a31582e3dcdc Mon Sep 17 00:00:00 2001
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From: Sylwester Nawrocki <s.nawrocki@samsung.com>
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Date: Mon, 4 May 2020 14:45:15 +0200
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Subject: [PATCH] usb: xhci: Use only 32-bit accesses in xhci_writeq/xhci_readq
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There might be hardware configurations where 64-bit data accesses
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to XHCI registers are not supported properly. This patch removes
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the readq/writeq so always two 32-bit accesses are used to read/write
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64-bit XHCI registers, similarly as it is done in Linux kernel.
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This patch fixes operation of the XHCI controller on RPI4 Broadcom
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BCM2711 SoC based board, where the VL805 USB XHCI controller is
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connected to the PCIe Root Complex, which is attached to the system
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through the SCB bridge.
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Even though the architecture is 64-bit the PCIe BAR is 32-bit and likely
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the 64-bit wide register accesses initiated by the CPU are not properly
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translated to a sequence of 32-bit PCIe accesses.
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xhci_readq(), for example, always returns same value in upper and lower
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32-bits, e.g. 0xabcd1234abcd1234 instead of 0x00000000abcd1234.
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Cc: Sergey Temerkhanov <s.temerkhanov@gmail.com>
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Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
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Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
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Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
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---
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include/usb/xhci.h | 8 --------
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1 file changed, 8 deletions(-)
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diff --git a/include/usb/xhci.h b/include/usb/xhci.h
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index 6017504488..c16106a2fc 100644
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--- a/include/usb/xhci.h
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+++ b/include/usb/xhci.h
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@@ -1111,28 +1111,20 @@ static inline void xhci_writel(uint32_t volatile *regs, const unsigned int val)
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*/
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static inline u64 xhci_readq(__le64 volatile *regs)
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{
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-#if BITS_PER_LONG == 64
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- return readq(regs);
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-#else
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__u32 *ptr = (__u32 *)regs;
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u64 val_lo = readl(ptr);
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u64 val_hi = readl(ptr + 1);
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return val_lo + (val_hi << 32);
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-#endif
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}
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static inline void xhci_writeq(__le64 volatile *regs, const u64 val)
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{
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-#if BITS_PER_LONG == 64
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- writeq(val, regs);
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-#else
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__u32 *ptr = (__u32 *)regs;
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u32 val_lo = lower_32_bits(val);
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/* FIXME */
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u32 val_hi = upper_32_bits(val);
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writel(val_lo, ptr);
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writel(val_hi, ptr + 1);
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-#endif
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}
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int xhci_hcd_init(int index, struct xhci_hccr **ret_hccr,
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