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Date: Wed, 23 Aug 2017 23:38:04 -0700 From: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com> To: Michael Ellerman <mpe@...erman.id.au> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>, mikey@...ling.org, stewart@...ux.vnet.ibm.com, apopple@....ibm.com, hbabu@...ibm.com, oohall@...il.com, linuxppc-dev@...abs.org, <linux-kernel@...r.kernel.org> Subject: [PATCH v7 08/12] powerpc/vas: Define vas_win_id() Define an interface to return a system-wide unique id for a given VAS window. The vas_win_id() will be used in a follow-on patch to generate an unique handle for a user space receive window. Applications can use this handle to pair send and receive windows for fast thread-wakeup. The hardware refers to this system-wide unique id as a Partition Send Window ID which is expected to be used during fault handling. Hence the "pswid" in the function names. Signed-off-by: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com> --- arch/powerpc/include/asm/vas.h | 5 +++++ arch/powerpc/platforms/powernv/vas-window.c | 9 +++++++++ arch/powerpc/platforms/powernv/vas.h | 28 ++++++++++++++++++++++++++++ 3 files changed, 42 insertions(+) diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h index 2f1c168..6c126f3 100644 --- a/arch/powerpc/include/asm/vas.h +++ b/arch/powerpc/include/asm/vas.h @@ -53,6 +53,11 @@ enum vas_cop_type { }; /* + * Return a system-wide unique id for the VAS window @win. + */ +extern uint32_t vas_win_id(struct vas_window *win); + +/* * Return the power bus paste address associated with @win so the caller * can map that address into their address space. */ diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c index 3a4599f..42c1d4f 100644 --- a/arch/powerpc/platforms/powernv/vas-window.c +++ b/arch/powerpc/platforms/powernv/vas-window.c @@ -575,3 +575,12 @@ int vas_win_close(struct vas_window *window) { return -1; } + +/* + * Return a system-wide unique window id for the window @win. + */ +uint32_t vas_win_id(struct vas_window *win) +{ + return encode_pswid(win->vinst->vas_id, win->winid); +} +EXPORT_SYMBOL_GPL(vas_win_id); diff --git a/arch/powerpc/platforms/powernv/vas.h b/arch/powerpc/platforms/powernv/vas.h index 7b2bcd0..3eadf90 100644 --- a/arch/powerpc/platforms/powernv/vas.h +++ b/arch/powerpc/platforms/powernv/vas.h @@ -440,4 +440,32 @@ static inline uint64_t read_hvwc_reg(struct vas_window *win, return in_be64(win->hvwc_map+reg); } +/* + * Encode/decode the Partition Send Window ID (PSWID) for a window in + * a way that we can uniquely identify any window in the system. i.e. + * we should be able to locate the 'struct vas_window' given the PSWID. + * + * Bits Usage + * 0:7 VAS id (8 bits) + * 8:15 Unused, 0 (3 bits) + * 16:31 Window id (16 bits) + */ +static inline u32 encode_pswid(int vasid, int winid) +{ + u32 pswid = 0; + + pswid |= vasid << (31 - 7); + pswid |= winid; + + return pswid; +} + +static inline void decode_pswid(u32 pswid, int *vasid, int *winid) +{ + if (vasid) + *vasid = pswid >> (31 - 7) & 0xFF; + + if (winid) + *winid = pswid & 0xFFFF; +} #endif /* _VAS_H */ -- 2.7.4
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