From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423786AbeE1LMX (ORCPT ); Mon, 28 May 2018 07:12:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:59988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938038AbeE1LMN (ORCPT ); Mon, 28 May 2018 07:12:13 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vaibhav Jain , Andrew Donnellan , Frederic Barrat , Michael Ellerman , Sasha Levin Subject: [PATCH 4.16 179/272] cxl: Check if PSL data-cache is available before issue flush request Date: Mon, 28 May 2018 12:03:32 +0200 Message-Id: <20180528100255.757970401@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100240.256525891@linuxfoundation.org> References: <20180528100240.256525891@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vaibhav Jain [ Upstream commit 94322ed8e857e3b2a33cf75118051af9baaa110f ] PSL9D doesn't have a data-cache that needs to be flushed before resetting the card. However when cxl tries to flush data-cache on such a card, it times-out as PSL_Control register never indicates flush operation complete due to missing data-cache. This is usually indicated in the kernel logs with this message: "WARNING: cache flush timed out" To fix this the patch checks PSL_Debug register CDC-Field(BIT:27) which indicates the absence of a data-cache and sets a flag 'no_data_cache' in 'struct cxl_native' to indicate this. When cxl_data_cache_flush() is called it checks the flag and if set bails out early without requesting a data-cache flush operation to the PSL. Signed-off-by: Vaibhav Jain Acked-by: Andrew Donnellan Acked-by: Frederic Barrat Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/misc/cxl/cxl.h | 4 ++++ drivers/misc/cxl/native.c | 11 ++++++++++- drivers/misc/cxl/pci.c | 19 +++++++++++++------ 3 files changed, 27 insertions(+), 7 deletions(-) --- a/drivers/misc/cxl/cxl.h +++ b/drivers/misc/cxl/cxl.h @@ -369,6 +369,9 @@ static const cxl_p2n_reg_t CXL_PSL_WED_A #define CXL_PSL_TFC_An_AE (1ull << (63-30)) /* Restart PSL with address error */ #define CXL_PSL_TFC_An_R (1ull << (63-31)) /* Restart PSL transaction */ +/****** CXL_PSL_DEBUG *****************************************************/ +#define CXL_PSL_DEBUG_CDC (1ull << (63-27)) /* Coherent Data cache support */ + /****** CXL_XSL9_IERAT_ERAT - CAIA 2 **********************************/ #define CXL_XSL9_IERAT_MLPID (1ull << (63-0)) /* Match LPID */ #define CXL_XSL9_IERAT_MPID (1ull << (63-1)) /* Match PID */ @@ -669,6 +672,7 @@ struct cxl_native { irq_hw_number_t err_hwirq; unsigned int err_virq; u64 ps_off; + bool no_data_cache; /* set if no data cache on the card */ const struct cxl_service_layer_ops *sl_ops; }; --- a/drivers/misc/cxl/native.c +++ b/drivers/misc/cxl/native.c @@ -353,8 +353,17 @@ int cxl_data_cache_flush(struct cxl *ada u64 reg; unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT); - pr_devel("Flushing data cache\n"); + /* + * Do a datacache flush only if datacache is available. + * In case of PSL9D datacache absent hence flush operation. + * would timeout. + */ + if (adapter->native->no_data_cache) { + pr_devel("No PSL data cache. Ignoring cache flush req.\n"); + return 0; + } + pr_devel("Flushing data cache\n"); reg = cxl_p1_read(adapter, CXL_PSL_Control); reg |= CXL_PSL_Control_Fr; cxl_p1_write(adapter, CXL_PSL_Control, reg); --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -456,6 +456,7 @@ static int init_implementation_adapter_r u64 chipid; u32 phb_index; u64 capp_unit_id; + u64 psl_debug; int rc; rc = cxl_calc_capp_routing(dev, &chipid, &phb_index, &capp_unit_id); @@ -506,6 +507,16 @@ static int init_implementation_adapter_r } else cxl_p1_write(adapter, CXL_PSL9_DEBUG, 0x4000000000000000ULL); + /* + * Check if PSL has data-cache. We need to flush adapter datacache + * when as its about to be removed. + */ + psl_debug = cxl_p1_read(adapter, CXL_PSL9_DEBUG); + if (psl_debug & CXL_PSL_DEBUG_CDC) { + dev_dbg(&dev->dev, "No data-cache present\n"); + adapter->native->no_data_cache = true; + } + return 0; } @@ -1449,10 +1460,8 @@ int cxl_pci_reset(struct cxl *adapter) /* * The adapter is about to be reset, so ignore errors. - * Not supported on P9 DD1 */ - if ((cxl_is_power8()) || (!(cxl_is_power9_dd1()))) - cxl_data_cache_flush(adapter); + cxl_data_cache_flush(adapter); /* pcie_warm_reset requests a fundamental pci reset which includes a * PERST assert/deassert. PERST triggers a loading of the image @@ -1936,10 +1945,8 @@ static void cxl_pci_remove_adapter(struc /* * Flush adapter datacache as its about to be removed. - * Not supported on P9 DD1. */ - if ((cxl_is_power8()) || (!(cxl_is_power9_dd1()))) - cxl_data_cache_flush(adapter); + cxl_data_cache_flush(adapter); cxl_deconfigure_adapter(adapter);