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Violators will be prosecuted for from ; Thu, 30 Mar 2017 23:14:16 -0600 From: Sukadev Bhattiprolu To: Michael Ellerman Cc: Benjamin Herrenschmidt , michael.neuling@au1.ibm.com, stewart@linux.vnet.ibm.com, apopple@au1.ibm.com, hbabu@us.ibm.com, oohall@gmail.com, bsingharora@gmail.com, linuxppc-dev@ozlabs.org, Subject: [PATCH v4 09/11] VAS: Define vas_win_close() interface Date: Thu, 30 Mar 2017 22:13:42 -0700 In-Reply-To: <1490937224-29149-1-git-send-email-sukadev@linux.vnet.ibm.com> References: <1490937224-29149-1-git-send-email-sukadev@linux.vnet.ibm.com> Message-Id: <1490937224-29149-10-git-send-email-sukadev@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Define the vas_win_close() interface which should be used to close a send or receive windows. While the hardware configurations required to open send and receive windows differ, the configuration to close a window is the same for both. So we use a single interface to close the window. Signed-off-by: Sukadev Bhattiprolu --- Changelog[v4]: - Drop the poll for credits return (we can set the required credit, but cannot really find the available credit at a point in time) Changelog[v3]: - Fix order of parameters in GET_FIELD(). - Update references and sequence for closing/quiescing a window. --- arch/powerpc/include/asm/vas.h | 7 +++ arch/powerpc/platforms/powernv/vas-window.c | 96 +++++++++++++++++++++++++++-- 2 files changed, 99 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h index 09ea6f7..c923b8f 100644 --- a/arch/powerpc/include/asm/vas.h +++ b/arch/powerpc/include/asm/vas.h @@ -76,4 +76,11 @@ extern void vas_init_rx_win_attr(struct vas_rx_win_attr *rxattr, extern struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop, struct vas_rx_win_attr *attr); +/* + * Close the send or receive window identified by @win. For receive windows + * return -EAGAIN if there are active send windows attached to this receive + * window. + */ +int vas_win_close(struct vas_window *win); + #endif /* _MISC_VAS_H */ diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c index 04f6bb2..7b1a36c 100644 --- a/arch/powerpc/platforms/powernv/vas-window.c +++ b/arch/powerpc/platforms/powernv/vas-window.c @@ -470,7 +470,7 @@ int vas_assign_window_id(struct ida *ida) return winid; } -void vas_window_free(struct vas_window *window) +static void vas_window_free(struct vas_window *window) { unmap_wc_mmio_bars(window); kfree(window->paste_addr_name); @@ -498,10 +498,12 @@ static struct vas_window *vas_window_alloc(struct vas_instance *vinst, int id) return NULL; } -/* stub for now */ -int vas_win_close(struct vas_window *window) +static void put_rx_win(struct vas_window *rxwin) { - return -1; + /* Better not be a send window! */ + WARN_ON_ONCE(rxwin->tx_win); + + atomic_dec(&rxwin->num_txwins); } struct vas_window *get_vinstance_rxwin(struct vas_instance *vinst, @@ -706,3 +708,89 @@ struct vas_window *vas_rx_win_open(int vasid, enum vas_cop_type cop, vas_release_window_id(&vinst->ida, rxwin->winid); return ERR_PTR(rc); } + +static void poll_window_busy_state(struct vas_window *window) +{ + int busy; + uint64_t val; + +retry: + /* + * Poll Window Busy flag + */ + val = read_hvwc_reg(window, VREG(WIN_STATUS)); + busy = GET_FIELD(VAS_WIN_BUSY, val); + if (busy) { + val = 0; + schedule_timeout(2000); + goto retry; + } +} + +static void poll_window_castout(struct vas_window *window) +{ + int cached; + uint64_t val; + + /* Cast window context out of the cache */ +retry: + val = read_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL)); + cached = GET_FIELD(VAS_WIN_CACHE_STATUS, val); + if (cached) { + val = 0ULL; + val = SET_FIELD(VAS_CASTOUT_REQ, val, 1); + val = SET_FIELD(VAS_PUSH_TO_MEM, val, 0); + write_hvwc_reg(window, VREG(WIN_CTX_CACHING_CTL), val); + + schedule_timeout(2000); + goto retry; + } +} + +/* + * Close a window. + * + * See Section 1.12.1 of VAS workbook v1.05 for details on closing window: + * - disable new paste operations (unmap paste address) + * - Poll for the "Window Busy" bit to be cleared + * - Clear the Open/Enable bit for the Window. + * - Poll for return of window Credits (implies FIFO empty for Rx win?) + * - Unpin and cast window context out of cache + * + * Besides the hardware, kernel has some bookkeeping of course. + */ +int vas_win_close(struct vas_window *window) +{ + uint64_t val; + + if (!window) + return 0; + + if (!window->tx_win && atomic_read(&window->num_txwins) != 0) { + pr_devel("VAS: Attempting to close an active Rx window!\n"); + WARN_ON_ONCE(1); + return -EAGAIN; + } + + unmap_wc_paste_kaddr(window); + + poll_window_busy_state(window); + + /* Unpin window from cache and close it */ + val = read_hvwc_reg(window, VREG(WINCTL)); + val = SET_FIELD(VAS_WINCTL_PIN, val, 0); + val = SET_FIELD(VAS_WINCTL_OPEN, val, 0); + write_hvwc_reg(window, VREG(WINCTL), val); + + poll_window_castout(window); + + /* if send window, drop reference to matching receive window */ + if (window->tx_win) + put_rx_win(window->rxwin); + + vas_release_window_id(&window->vinst->ida, window->winid); + + vas_window_free(window); + + return 0; +} -- 2.7.4