From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9F1A3C88E45 for ; Fri, 11 Sep 2026 15:13:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VDQ4nMhA4Jo2TyzF3CNcQNgbsusJXkUMzgKVjsG4070=; b=Nb6rM8BLoELPckQ67dDEbz7pSx alfYmG9g1UFeM+r9VHm4A0H8mFXXdCJVgaCfhjx1YyZC6zLGA/eXGqQumuPm1X/uGHGyZq/LHpCPR aRbsclBTL3KajQxbfozqXUyFqhuZAN2rExEWhnfVCd8rGaG/xPOkb1ymhCG65eda6VlBI9A1L48Cq Rlly47ui0+iFp7KW0/IsReqPbVybIeqfjkHOOclFGX4PtRhbibaH+1/Bxm7e14cGCH0BzMJCTsspw Ic7DXqY4pqTe5MVfs7OFwtAWX9XTrPpy76T+uFE5bmgp4IFj+8lVfTOVo42L0eezMWChrtLSFiuh0 qiOJViog==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x52wW-0000000H0wb-2GFy; Fri, 11 Sep 2026 15:13:32 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x52wT-0000000H0wH-2s2y for linux-arm-kernel@lists.infradead.org; Fri, 11 Sep 2026 15:13:31 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5B84316A3; Fri, 11 Sep 2026 08:13:24 -0700 (PDT) Received: from [10.2.212.8] (e134344.arm.com [10.2.212.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7A3DC3F8C6; Fri, 11 Sep 2026 08:13:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789139608; bh=rlNpwmOkY6W0zl5ISCgzQhL95mZvrDg3MLqfuB4U2pM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=cAnRF6Ed/jMyDmLGy4Aqw69/mRwaCpg7d2KPcWQS9NH/xOhDFsIRjWWnWa0aDL19S sjebD42NTr96cFTA1ZfW3WEuDn8Ys8HKgQOOWIZPe/0kcDSMnyjeUpRj5nrVsfqQq1 DXnowQYtSiOrT8znHtv4+66tL+eP2eUKjkGa1j2I= Message-ID: Date: Fri, 11 Sep 2026 16:13:24 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 10/14] arm_mpam: add MPAM-Fb MSC firmware access support To: Andre Przywara , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Reinette Chatre , Fenghua Yu Cc: Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , Lee Trager , Ritwick Sharma , Gavin Shan , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260911112835.714162-1-andre.przywara@arm.com> <20260911112835.714162-11-andre.przywara@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20260911112835.714162-11-andre.przywara@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260911_081329_856649_426BB373 X-CRM114-Status: GOOD ( 35.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Andre, On 11/09/2026 12:28, Andre Przywara wrote: > The Arm MPAM Firmware-backed (Fb) Profile document[1] describes an > alternative way of accessing the "Memory System Components" (MSC) in an > MPAM enabled system. > > Normally the MSCs are MMIO mapped, but in some implementations this > might not be possible (MSC located outside of the local socket, MSC > mapped secure-only) or desirable (direct MMIO access too slow or needs > to be mediated through a control processor). MPAM-fb standardises a > protocol to abstract MSC accesses, building on the SCMI protocol. > > Add functions that do an MSC read or write access by redirecting the > request through a firmware interface. For now this done via an ACPI > PCC shared memory and mailbox combination. > > Since the protocol used is only a small subset of the full SCMI spec, > and the SCMI protocol has no full ACPI support anyway, open-code the > (simple) SCMI message generation, for just the fields we need. > > [1] https://developer.arm.com/documentation/den0144/latest > > Signed-off-by: Andre Przywara > Reviewed-by: Jonathan Cameron > Tested-by: Ritwick Sharma # on Arm AGI CPU > Reviewed-by: Gavin Shan > Reviewed-by: Srivathsa L Rao > --- > drivers/acpi/arm64/mpam.c | 2 + > drivers/resctrl/Kconfig | 1 + > drivers/resctrl/Makefile | 2 +- > drivers/resctrl/mpam_devices.c | 65 ++++++++-- > drivers/resctrl/mpam_fb.c | 211 ++++++++++++++++++++++++++++++++ > drivers/resctrl/mpam_internal.h | 19 +++ > include/linux/arm_mpam.h | 2 +- > 7 files changed, 288 insertions(+), 14 deletions(-) > create mode 100644 drivers/resctrl/mpam_fb.c > > diff --git a/drivers/acpi/arm64/mpam.c b/drivers/acpi/arm64/mpam.c > index 84963a20c3e78..09c7af6bca69e 100644 > --- a/drivers/acpi/arm64/mpam.c > +++ b/drivers/acpi/arm64/mpam.c > @@ -256,6 +256,8 @@ static struct platform_device * __init acpi_mpam_parse_msc(struct acpi_mpam_msc_ > } else if (iface == MPAM_IFACE_PCC) { > props[next_prop++] = PROPERTY_ENTRY_U32("pcc-channel", > tbl_msc->base_address); > + props[next_prop++] = PROPERTY_ENTRY_U32("mpam-fb-msc-id", > + tbl_msc->identifier); > } > > acpi_mpam_parse_irqs(pdev, tbl_msc, res, &next_res); > diff --git a/drivers/resctrl/Kconfig b/drivers/resctrl/Kconfig > index 672abea3b03cc..9591d792736e5 100644 > --- a/drivers/resctrl/Kconfig > +++ b/drivers/resctrl/Kconfig > @@ -2,6 +2,7 @@ menuconfig ARM64_MPAM_DRIVER > bool "MPAM driver" > depends on ARM64 && ARM64_MPAM > select ACPI_MPAM if ACPI > + select MAILBOX > help > Memory System Resource Partitioning and Monitoring (MPAM) driver for > System IP, e.g. caches and memory controllers. > diff --git a/drivers/resctrl/Makefile b/drivers/resctrl/Makefile > index 4f6d0e81f9b8f..097c036724e97 100644 > --- a/drivers/resctrl/Makefile > +++ b/drivers/resctrl/Makefile > @@ -1,5 +1,5 @@ > obj-$(CONFIG_ARM64_MPAM_DRIVER) += mpam.o > -mpam-y += mpam_devices.o > +mpam-y += mpam_devices.o mpam_fb.o > mpam-$(CONFIG_ARM64_MPAM_RESCTRL_FS) += mpam_resctrl.o > > ccflags-$(CONFIG_ARM64_MPAM_DRIVER_DEBUG) += -DDEBUG > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index e7c239a496f7a..745f27845e3af 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -82,6 +83,21 @@ static DECLARE_WORK(mpam_broken_work, &mpam_disable); > > /* When mpam is disabled, the printed reason to aid debugging */ > static char *mpam_disable_reason; > +static int mpam_disable_errno; > +static int mpam_disable_mpam_fb_err; > + > +void mpam_fb_disable_mpam(int err, int mpam_fb_err) > +{ > + /* Prevent repeated calls when mpam_disable() does MSC accesses. */ > + if (!mpam_is_enabled()) > + return; > + > + mpam_disable_errno = err; > + mpam_disable_mpam_fb_err = mpam_fb_err; > + > + mpam_disable_reason = "MPAM-Fb error"; > + schedule_work(&mpam_broken_work); > +} > > /* > * Whether resctrl has been setup. Used by cpuhp in preference to > @@ -179,8 +195,11 @@ static void mpam_assert_partid_sizes_fixed(void) > > static int __mpam_read_reg(struct mpam_msc *msc, u16 reg, u32 *res) > { > - WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > > + if (msc->iface == MPAM_IFACE_PCC) > + return mpam_fb_send_read_request(msc, reg, res); > + > + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > *res = readl_relaxed(msc->mapped_hwpage + reg); > > return 0; > @@ -197,9 +216,12 @@ static inline int _mpam_read_partsel_reg(struct mpam_msc *msc, u16 reg, > > static int __mpam_write_reg(struct mpam_msc *msc, u16 reg, u32 val) > { > - WARN_ON_ONCE(reg + sizeof(u32) > msc->mapped_hwpage_sz); > - WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > > + if (msc->iface == MPAM_IFACE_PCC) > + return mpam_fb_send_write_request(msc, reg, val); > + > + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > + WARN_ON_ONCE(reg + sizeof(u32) > msc->mapped_hwpage_sz); > writel_relaxed(val, msc->mapped_hwpage + reg); > > return 0; > @@ -1143,8 +1165,11 @@ static int mpam_msc_read_mbwu_l(struct mpam_msc *msc, u64 *res) > > mpam_mon_sel_lock_held(msc); > > - WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); > - WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > + if (msc->iface == MPAM_IFACE_MMIO) { > + WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); > + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), > + &msc->accessibility)); > + } > > ret = __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2); > if (ret) > @@ -1178,8 +1203,11 @@ static int mpam_msc_zero_mbwu_l(struct mpam_msc *msc) > > mpam_mon_sel_lock_held(msc); > > - WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); > - WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); > + if (msc->iface == MPAM_IFACE_MMIO) { > + WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); > + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), > + &msc->accessibility)); > + } > > ret = __mpam_write_reg(msc, MSMON_MBWU_L, 0); > if (ret) > @@ -1490,11 +1518,16 @@ static int _msmon_read(struct mpam_component *comp, struct mon_read *arg) > srcu_read_lock_held(&mpam_srcu)) { > arg->ris = ris; > > - err = smp_call_function_any(&msc->accessibility, > - __ris_msmon_read, arg, > - true); > - if (!err && arg->err) > + if (msc->iface == MPAM_IFACE_MMIO) { > + err = smp_call_function_any(&msc->accessibility, > + __ris_msmon_read, > + arg, true); > + if (!err) > + err = arg->err; > + } else { > + __ris_msmon_read(arg); > err = arg->err; > + } > > /* > * Save one error to be returned to the caller, but > @@ -1977,6 +2010,9 @@ static int mpam_get_msc_preferred_cpu(struct mpam_msc *msc) > > static int mpam_touch_msc(struct mpam_msc *msc, int (*fn)(void *a), void *arg) > { > + if (msc->iface != MPAM_IFACE_MMIO) > + return fn(arg); > + > lockdep_assert_irqs_enabled(); > lockdep_assert_cpus_held(); > WARN_ON_ONCE(!srcu_read_lock_held((&mpam_srcu))); > @@ -3090,7 +3126,12 @@ void mpam_disable(struct work_struct *ignored) > mutex_unlock(&mpam_list_lock); > mpam_free_garbage(); > > - pr_err_once("MPAM disabled due to %s\n", mpam_disable_reason); > + if (mpam_disable_errno || mpam_disable_mpam_fb_err) > + pr_err_once("MPAM disabled due to %s: %s, MPAM-Fb error %d\n", > + mpam_disable_reason, errname(mpam_disable_errno), > + mpam_disable_mpam_fb_err); > + else > + pr_err_once("MPAM disabled due to %s\n", mpam_disable_reason); > } > > /* > diff --git a/drivers/resctrl/mpam_fb.c b/drivers/resctrl/mpam_fb.c > new file mode 100644 > index 0000000000000..98212f761de38 > --- /dev/null > +++ b/drivers/resctrl/mpam_fb.c > @@ -0,0 +1,211 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2024-2026 Arm Ltd. > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > + > +#include "mpam_internal.h" > + > +#define MPAM_MSC_TOKEN_MASK GENMASK_U32(27, 18) > +#define MPAM_MSC_PROT_ID_MASK GENMASK_U32(17, 10) > + > +#define MPAM_FB_PROTOCOL_ID 0x1a > + > +#define MPAM_PROTOCOL_VERSION_CMD 0x0 > +#define MPAM_MSC_READ_CMD 0x4 > +#define MPAM_MSC_WRITE_CMD 0x5 > + > +#define MPAM_FB_PROT_HEADER_LEN sizeof(u32) > + > +#define MPAM_FB_SUCCESS 0 > +#define MPAM_FB_ERR_NOT_SUPPORTED -1 > +#define MPAM_FB_ERR_INVALID_PARAMETERS -2 > +#define MPAM_FB_ERR_DENIED -3 > +#define MPAM_FB_ERR_NOT_FOUND -4 > +#define MPAM_FB_ERR_OUT_OF_RANGE -5 > +#define MPAM_FB_ERR_BUSY -6 > +#define MPAM_FB_ERR_COMMS_ERROR -7 > +#define MPAM_FB_ERR_GENERIC_ERROR -8 > +#define MPAM_FB_ERR_HW_ERROR -9 > +#define MPAM_FB_ERR_PROTOCOL_ERROR -10 > +#define MPAM_FB_ERR_IN_USE -11 > + > +static atomic_t mpam_fb_token = ATOMIC_INIT(0); > + > +static int mpam_fb_to_linux_errno(int mpam_fb_code) > +{ > + switch (mpam_fb_code) { > + case MPAM_FB_ERR_NOT_SUPPORTED: > + return -EOPNOTSUPP; > + case MPAM_FB_ERR_INVALID_PARAMETERS: > + return -EINVAL; > + case MPAM_FB_ERR_NOT_FOUND: > + return -ENOENT; > + case MPAM_FB_ERR_OUT_OF_RANGE: > + return -ERANGE; > + case MPAM_FB_ERR_BUSY: > + return -EBUSY; > + default: > + return -EINVAL; > + } > +} > + > +static void mpam_fb_build_version_message(unsigned int token, > + void __iomem *msg_buf) > +{ > + struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_shmem = msg_buf; > + > + /* .signature is filled by the platform */ > + writel_relaxed(PCC_CMD_COMPLETION_NOTIFY, &pcc_shmem->flags); > + writel_relaxed(MPAM_FB_PROT_HEADER_LEN, &pcc_shmem->length); > + writel_relaxed(MPAM_PROTOCOL_VERSION_CMD | > + FIELD_PREP(MPAM_MSC_TOKEN_MASK, token) | > + FIELD_PREP(MPAM_MSC_PROT_ID_MASK, MPAM_FB_PROTOCOL_ID), > + &pcc_shmem->command); > +} > + > +static void mpam_fb_build_read_message(int msc_id, int reg, unsigned int token, > + void __iomem *msg_buf) As we're anticipating that msc_id may be different from msc->id can be use msc_fb_id instead of msc_id in this file. Thanks, Ben > +{ > + struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_shmem = msg_buf; > + struct mpam_fb_read_payload { > + u32 msc_id; > + u32 flags; > + u32 reg_offset; > + } __packed __iomem *payload = msg_buf + sizeof(*pcc_shmem); > + int msg_size = MPAM_FB_PROT_HEADER_LEN + sizeof(*payload); > + > + /* .signature is filled by the platform */ > + writel_relaxed(PCC_CMD_COMPLETION_NOTIFY, &pcc_shmem->flags); > + writel_relaxed(msg_size, &pcc_shmem->length); > + writel_relaxed(MPAM_MSC_READ_CMD | > + FIELD_PREP(MPAM_MSC_TOKEN_MASK, token) | > + FIELD_PREP(MPAM_MSC_PROT_ID_MASK, MPAM_FB_PROTOCOL_ID), > + &pcc_shmem->command); > + > + writel_relaxed(msc_id, &payload->msc_id); > + writel_relaxed(0, &payload->flags); > + writel_relaxed(reg, &payload->reg_offset); > +} > + > +static void mpam_fb_build_write_message(int msc_id, int reg, u32 val, > + unsigned int token, > + void __iomem *msg_buf) > +{ > + struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_shmem = msg_buf; > + struct mpam_fb_write_payload { > + u32 msc_id; > + u32 flags; > + u32 reg_offset; > + u32 value; > + } __packed __iomem *payload = msg_buf + sizeof(*pcc_shmem); > + int msg_size = MPAM_FB_PROT_HEADER_LEN + sizeof(*payload); > + > + /* .signature is filled by the platform */ > + writel_relaxed(PCC_CMD_COMPLETION_NOTIFY, &pcc_shmem->flags); > + writel_relaxed(msg_size, &pcc_shmem->length); > + writel_relaxed(MPAM_MSC_WRITE_CMD | > + FIELD_PREP(MPAM_MSC_TOKEN_MASK, token) | > + FIELD_PREP(MPAM_MSC_PROT_ID_MASK, MPAM_FB_PROTOCOL_ID), > + &pcc_shmem->command); > + > + writel_relaxed(msc_id, &payload->msc_id); > + writel_relaxed(0, &payload->flags); > + writel_relaxed(reg, &payload->reg_offset); > + writel_relaxed(val, &payload->value); > +} > + > +static int mpam_fb_send_request(struct mpam_msc *msc, u32 msc_id, > + u16 reg, u32 *result, int mpam_fb_command) > +{ > + unsigned int token = atomic_inc_return(&mpam_fb_token); > + struct acpi_pcct_ext_pcc_shared_memory __iomem *pcc_shmem; > + struct mpam_pcc_chan *pcc_chan; > + struct pcc_mbox_chan *chan; > + void __iomem *payload_ofs; > + int mpam_fb_err = 0; > + u32 status; > + int ret; > + > + pcc_chan = msc->pcc_chan; > + if (!pcc_chan) > + return -ENODEV; > + > + chan = pcc_chan->pcc_chan; > + > + /* prune token to fit into the 10 bits inside the command register */ > + token = FIELD_GET(MPAM_MSC_TOKEN_MASK, > + FIELD_PREP(MPAM_MSC_TOKEN_MASK, token)); > + > + mutex_lock(&pcc_chan->pcc_chan_lock); > + > + switch (mpam_fb_command) { > + case MPAM_PROTOCOL_VERSION_CMD: > + mpam_fb_build_version_message(token, chan->shmem); > + break; > + case MPAM_MSC_READ_CMD: > + mpam_fb_build_read_message(msc_id, reg, token, chan->shmem); > + break; > + case MPAM_MSC_WRITE_CMD: > + mpam_fb_build_write_message(msc_id, reg, *result, > + token, chan->shmem); > + break; > + default: > + dev_err(&msc->pdev->dev, "unsupported MPAM-Fb command %d\n", > + mpam_fb_command); > + ret = -EINVAL; > + goto out_err; > + } > + > + ret = mbox_send_message(chan->mchan, NULL); > + if (ret < 0) > + goto out_err; > + > + pcc_shmem = chan->shmem; > + payload_ofs = chan->shmem + sizeof(*pcc_shmem); > + status = readl(&pcc_shmem->command); > + if (FIELD_GET(MPAM_MSC_TOKEN_MASK, status) != token) { > + ret = -ETIMEDOUT; > + goto out_err; > + } > + > + mpam_fb_err = readl(payload_ofs + 0x0); > + if (mpam_fb_err < 0) { > + ret = mpam_fb_to_linux_errno(mpam_fb_err); > + goto out_err; > + } > + > + if (mpam_fb_command != MPAM_MSC_WRITE_CMD) > + *result = readl(payload_ofs + 0x4); > + > + mutex_unlock(&pcc_chan->pcc_chan_lock); > + > + return 0; > + > +out_err: > + mutex_unlock(&pcc_chan->pcc_chan_lock); > + > + mpam_fb_disable_mpam(ret, mpam_fb_err); > + > + return ret; > +} > + > +int mpam_fb_send_read_request(struct mpam_msc *msc, u16 reg, u32 *result) > +{ > + return mpam_fb_send_request(msc, msc->mpam_fb_msc_id, reg, result, > + MPAM_MSC_READ_CMD); > +} > + > +int mpam_fb_send_write_request(struct mpam_msc *msc, u16 reg, u32 value) > +{ > + return mpam_fb_send_request(msc, msc->mpam_fb_msc_id, reg, &value, > + MPAM_MSC_WRITE_CMD); > +} > diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h > index 2414598100140..e5a2804facd2d 100644 > --- a/drivers/resctrl/mpam_internal.h > +++ b/drivers/resctrl/mpam_internal.h > @@ -11,6 +11,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -57,6 +58,15 @@ struct mpam_garbage { > struct platform_device *pdev; > }; > > +struct mpam_pcc_chan { > + struct list_head pcc_chans; > + struct mbox_client pcc_cl; > + struct pcc_mbox_chan *pcc_chan; > + struct mutex pcc_chan_lock; /* only one message at a time */ > + struct kref refcount; > + int subspace_id; > +}; > + > struct mpam_msc { > /* member of mpam_all_msc */ > struct list_head all_msc_list; > @@ -66,6 +76,8 @@ struct mpam_msc { > > /* Not modified after mpam_is_enabled() becomes true */ > enum mpam_msc_iface iface; > + struct mpam_pcc_chan *pcc_chan; > + int mpam_fb_msc_id; > u32 nrdy_usec; > cpumask_t accessibility; > bool has_extd_esr; > @@ -493,6 +505,9 @@ extern u8 mpam_pmg_max; > void mpam_enable(struct work_struct *work); > void mpam_disable(struct work_struct *work); > > +/* helper function to call from outside mpam_devices.c */ > +void mpam_fb_disable_mpam(int err, int mpam_fb_err); > + > /* Reset all the RIS in a class under cpus_read_lock() */ > void mpam_reset_class_locked(struct mpam_class *class); > > @@ -520,6 +535,10 @@ static inline void mpam_resctrl_offline_cpu(unsigned int cpu) { } > static inline void mpam_resctrl_teardown_class(struct mpam_class *class) { } > #endif /* CONFIG_RESCTRL_FS */ > > +/* MPAM-Fb Firmware-backed protocol wrappers */ > +int mpam_fb_send_read_request(struct mpam_msc *msc, u16 reg, u32 *result); > +int mpam_fb_send_write_request(struct mpam_msc *msc, u16 reg, u32 value); > + > /* > * MPAM MSCs have the following register layout. See: > * Arm Memory System Resource Partitioning and Monitoring (MPAM) System > diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h > index f92a36187a527..002f56e153626 100644 > --- a/include/linux/arm_mpam.h > +++ b/include/linux/arm_mpam.h > @@ -12,7 +12,7 @@ struct mpam_msc; > > enum mpam_msc_iface { > MPAM_IFACE_MMIO, /* a real MPAM MSC */ > - MPAM_IFACE_PCC, /* a fake MPAM MSC */ > + MPAM_IFACE_PCC, /* using the MPAM-Fb firmware redirection */ > }; > > enum mpam_class_types {