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Message-ID: <CAAfSe-su3k+7oJRbC04cYvLUrmSsAD2h=DUE0B-gVAoad0nJgA@mail.gmail.com>
Date: Wed, 27 Jan 2021 20:21:09 +0800
From: Chunyan Zhang <zhang.lyra@...il.com>
To: Robin Murphy <robin.murphy@....com>
Cc: Joerg Roedel <joro@...tes.org>, Rob Herring <robh+dt@...nel.org>,
DTML <devicetree@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Chunyan Zhang <chunyan.zhang@...soc.com>,
Sheng Xu <sheng.xu@...soc.com>,
iommu@...ts.linux-foundation.org,
Kevin Tang <kevin.tang@...soc.com>,
Baolin Wang <baolin.wang7@...il.com>,
Orson Zhai <orsonzhai@...il.com>, gavin.li@...soc.com
Subject: Re: [PATCH v1 2/2] iommu: add Unisoc iommu basic driver
On Fri, 22 Jan 2021 at 05:46, Robin Murphy <robin.murphy@....com> wrote:
>
> On 2021-01-21 11:23, Chunyan Zhang wrote:
> > From: Chunyan Zhang <chunyan.zhang@...soc.com>
> >
> > This patch only adds display iommu support, the driver was tested with sprd
> > dpu and image codec processor.
> >
> > The iommu support for others would be added once finished tests with those
> > devices, such as a few signal processors, including VSP(video),
> > GSP(graphic), ISP(image), and camera CPP, etc.
> >
> > Signed-off-by: Chunyan Zhang <chunyan.zhang@...soc.com>
> > ---
> > drivers/iommu/Kconfig | 12 +
> > drivers/iommu/Makefile | 1 +
> > drivers/iommu/sprd-iommu.c | 566 +++++++++++++++++++++++++++++++++++++
> > 3 files changed, 579 insertions(+)
> > create mode 100644 drivers/iommu/sprd-iommu.c
> >
> > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > index 192ef8f61310..79af62c519ae 100644
> > --- a/drivers/iommu/Kconfig
> > +++ b/drivers/iommu/Kconfig
> > @@ -408,4 +408,16 @@ config VIRTIO_IOMMU
> >
> > Say Y here if you intend to run this kernel as a guest.
> >
> > +config SPRD_IOMMU
> > + tristate "Unisoc IOMMU Support"
> > + depends on ARCH_SPRD || COMPILE_TEST
> > + select IOMMU_API
> > + help
> > + Support for IOMMU on Unisoc's SoCs on which multi-media subsystems
> > + need IOMMU, such as DPU, Image codec(jpeg) processor, and a few
> > + signal processors, including VSP(video), GSP(graphic), ISP(image), and
> > + CPP, etc.
> > +
> > + Say Y here if you want multi-media functions.
> > +
> > endif # IOMMU_SUPPORT
> > diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> > index 61bd30cd8369..5925b6af2123 100644
> > --- a/drivers/iommu/Makefile
> > +++ b/drivers/iommu/Makefile
> > @@ -28,3 +28,4 @@ obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
> > obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o
> > obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
> > obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o
> > +obj-$(CONFIG_SPRD_IOMMU) += sprd-iommu.o
> > diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
> > new file mode 100644
> > index 000000000000..44cde44017fa
> > --- /dev/null
> > +++ b/drivers/iommu/sprd-iommu.c
> > @@ -0,0 +1,566 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Unisoc IOMMU driver
> > + *
> > + * Copyright (C) 2020 Unisoc, Inc.
> > + * Author: Chunyan Zhang <chunyan.zhang@...soc.com>
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/device.h>
> > +#include <linux/dma-iommu.h>
>
> You need <linux/dma-mapping.h> since you're using the DMA API.
>
> > +#include <linux/errno.h>
> > +#include <linux/iommu.h>
> > +#include <linux/module.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/slab.h>
> > +
> > +/* SPRD IOMMU page is 4K size alignment */
> > +#define SPRD_IOMMU_PAGE_SHIFT 12
> > +#define SPRD_IOMMU_PAGE_SIZE SZ_4K
> > +
> > +#define SPRD_EX_CFG 0x0
> > +#define SPRD_IOMMU_VAOR_BYPASS BIT(4)
> > +#define SPRD_IOMMU_GATE_EN BIT(1)
> > +#define SPRD_IOMMU_EN BIT(0)
> > +#define SPRD_EX_UPDATE 0x4
> > +#define SPRD_EX_FIRST_VPN 0x8
> > +#define SPRD_EX_VPN_RANGE 0xc
> > +#define SPRD_EX_FIRST_PPN 0x10
> > +#define SPRD_EX_DEFAULT_PPN 0x14
> > +
> > +#define SPRD_IOMMU_VERSION 0x0
> > +#define SPRD_VERSION_MASK GENMASK(15, 8)
> > +#define SPRD_VERSION_SHIFT 0x8
> > +#define SPRD_VAU_CFG 0x4
> > +#define SPRD_VAU_UPDATE 0x8
> > +#define SPRD_VAU_AUTH_CFG 0xc
> > +#define SPRD_VAU_FIRST_PPN 0x10
> > +#define SPRD_VAU_DEFAULT_PPN_RD 0x14
> > +#define SPRD_VAU_DEFAULT_PPN_WR 0x18
> > +#define SPRD_VAU_FIRST_VPN 0x1c
> > +#define SPRD_VAU_VPN_RANGE 0x20
> > +
> > +enum sprd_iommu_version {
> > + SPRD_IOMMU_EX,
> > + SPRD_IOMMU_VAU,
> > +};
> > +
> > +struct sprd_iommu_match_data {
> > + unsigned long reg_offset;
> > +};
> > +
> > +/*
> > + * struct sprd_iommu_device - high-level sprd iommu device representation,
> > + * including hardware information and configuration, also driver data, etc
> > + *
> > + * @mdata: hardware configuration and information
> > + * @ver: sprd iommu device version
> > + * @prot_page: protect page base address, data would be written to here
> > + * while translation fault
> > + * @base: mapped base address for accessing registers
> > + * @dev: pointer to basic device structure
> > + * @iommu: IOMMU core representation
> > + * @group: IOMMU group
> > + */
> > +struct sprd_iommu_device {
> > + const struct sprd_iommu_match_data *mdata;
> > + enum sprd_iommu_version ver;
> > + u32 *prot_page_va;
> > + dma_addr_t prot_page_pa;
> > + void __iomem *base;
> > + struct device *dev;
> > + struct iommu_device iommu;
> > + struct iommu_group *group;
> > +};
> > +
> > +struct sprd_iommu_domain {
> > + spinlock_t pgtlock; /* lock for page table */
> > + struct iommu_domain domain;
> > + u32 *pgt_va; /* page table virtual address base */
> > + dma_addr_t pgt_pa; /* page table physical address base */
> > + struct sprd_iommu_device *sdev;
> > +};
> > +
> > +static const struct iommu_ops sprd_iommu_ops;
> > +
> > +static struct sprd_iommu_domain *to_sprd_domain(struct iommu_domain *dom)
> > +{
> > + return container_of(dom, struct sprd_iommu_domain, domain);
> > +}
> > +
> > +static inline void
> > +sprd_iommu_writel(struct sprd_iommu_device *sdev, unsigned int reg, u32 val)
> > +{
> > + writel_relaxed(val, sdev->base + sdev->mdata->reg_offset + reg);
> > +}
> > +
> > +static inline u32
> > +sprd_iommu_readl(struct sprd_iommu_device *sdev, unsigned int reg)
> > +{
> > + return readl_relaxed(sdev->base + sdev->mdata->reg_offset + reg);
> > +}
> > +
> > +static inline void
> > +sprd_iommu_update_bits(struct sprd_iommu_device *sdev, unsigned int reg,
> > + u32 mask, u32 shift, u32 val)
> > +{
> > + u32 t = sprd_iommu_readl(sdev, reg);
> > +
> > + t = (t & (~(mask << shift))) | ((val & mask) << shift);
> > + sprd_iommu_writel(sdev, reg, t);
> > +}
> > +
> > +static inline int
> > +sprd_iommu_get_version(struct sprd_iommu_device *sdev)
> > +{
> > + int ver = (sprd_iommu_readl(sdev, SPRD_IOMMU_VERSION) &
> > + SPRD_VERSION_MASK) >> SPRD_VERSION_SHIFT;
> > +
> > + switch (ver) {
> > + case SPRD_IOMMU_EX:
> > + case SPRD_IOMMU_VAU:
> > + return ver;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static size_t
> > +sprd_iommu_pgt_size(struct iommu_domain *domain)
> > +{
> > + return (size_t) (((domain->geometry.aperture_end -
> > + domain->geometry.aperture_start + 1) >>
> > + SPRD_IOMMU_PAGE_SHIFT) * 4);
>
> Nit: it's *reasonably* obvious, but "sizeof(u32)" might be more
> foolproof than just "4".
>
> Also the cast doesn't do anything that the implicit conversion in the
> return doesn't already.
>
> > +}
> > +
> > +static struct iommu_domain *sprd_iommu_domain_alloc(unsigned int domain_type)
> > +{
> > + struct sprd_iommu_domain *dom;
> > +
> > + if (domain_type != IOMMU_DOMAIN_DMA && domain_type != IOMMU_DOMAIN_UNMANAGED)
> > + return NULL;
> > +
> > + dom = kzalloc(sizeof(*dom), GFP_KERNEL);
> > + if (!dom)
> > + return NULL;
> > +
> > + if (iommu_get_dma_cookie(&dom->domain)) {
> > + kfree(dom);
> > + return NULL;
> > + }
> > +
> > + spin_lock_init(&dom->pgtlock);
> > +
> > + dom->domain.geometry.aperture_start = 0;
> > + dom->domain.geometry.aperture_end = SZ_256M - 1;
> > +
> > + return &dom->domain;
> > +}
> > +
> > +static void sprd_iommu_domain_free(struct iommu_domain *domain)
> > +{
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > +
>
> iommu_put_dma_cookie(domain);
>
> > + kfree(dom);
> > +}
> > +
> > +static void sprd_iommu_first_vpn(struct sprd_iommu_domain *dom)
> > +{
> > + struct sprd_iommu_device *sdev = dom->sdev;
> > + u32 val;
> > + unsigned int reg;
> > +
> > + if (sdev->ver == SPRD_IOMMU_EX)
> > + reg = SPRD_EX_FIRST_VPN;
> > + else
> > + reg = SPRD_VAU_FIRST_VPN;
> > +
> > + val = dom->domain.geometry.aperture_start >> SPRD_IOMMU_PAGE_SHIFT;
> > + sprd_iommu_writel(sdev, reg, val);
> > +}
> > +
> > +static void sprd_iommu_vpn_range(struct sprd_iommu_domain *dom)
> > +{
> > + struct sprd_iommu_device *sdev = dom->sdev;
> > + u32 val;
> > + unsigned int reg;
> > +
> > + if (sdev->ver == SPRD_IOMMU_EX)
> > + reg = SPRD_EX_VPN_RANGE;
> > + else
> > + reg = SPRD_VAU_VPN_RANGE;
> > +
> > + val = (dom->domain.geometry.aperture_end -
> > + dom->domain.geometry.aperture_start) >> SPRD_IOMMU_PAGE_SHIFT;
> > + sprd_iommu_writel(sdev, reg, val);
> > +}
> > +
> > +static void sprd_iommu_first_ppn(struct sprd_iommu_domain *dom)
> > +{
> > + u32 val = dom->pgt_pa >> SPRD_IOMMU_PAGE_SHIFT;
> > + struct sprd_iommu_device *sdev = dom->sdev;
> > + unsigned int reg;
> > +
> > + if (sdev->ver == SPRD_IOMMU_EX)
> > + reg = SPRD_EX_FIRST_PPN;
> > + else
> > + reg = SPRD_VAU_FIRST_PPN;
> > +
> > + sprd_iommu_writel(sdev, reg, val);
> > +}
> > +
> > +static void sprd_iommu_default_ppn(struct sprd_iommu_device *sdev)
> > +{
> > + u32 val = sdev->prot_page_pa >> SPRD_IOMMU_PAGE_SHIFT;
> > +
> > + if (sdev->ver == SPRD_IOMMU_EX) {
> > + sprd_iommu_writel(sdev, SPRD_EX_DEFAULT_PPN, val);
> > + } else if (sdev->ver == SPRD_IOMMU_VAU) {
> > + sprd_iommu_writel(sdev, SPRD_VAU_DEFAULT_PPN_RD, val);
> > + sprd_iommu_writel(sdev, SPRD_VAU_DEFAULT_PPN_WR, val);
> > + }
> > +}
> > +
> > +static void sprd_iommu_hw_en(struct sprd_iommu_device *sdev, bool en)
> > +{
> > + unsigned int reg_cfg;
> > + u32 mask, val;
> > +
> > + if (sdev->ver == SPRD_IOMMU_EX)
> > + reg_cfg = SPRD_EX_CFG;
> > + else
> > + reg_cfg = SPRD_VAU_CFG;
> > +
> > + /* enable mmu, clk gate, vaor bypass */
> > + mask = SPRD_IOMMU_EN | SPRD_IOMMU_GATE_EN | SPRD_IOMMU_VAOR_BYPASS;
> > + val = en ? mask : 0;
> > + sprd_iommu_update_bits(sdev, reg_cfg, mask, 0, val);
> > +}
> > +
> > +static int sprd_iommu_attach_device(struct iommu_domain *domain,
> > + struct device *dev)
> > +{
> > + struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > + size_t pgt_size = sprd_iommu_pgt_size(domain);
>
> If you're only supporting a single device per domain you should bail out
> here if dom->sdev is already set.
>
> > + dom->pgt_va = dma_alloc_coherent(sdev->dev, pgt_size, &dom->pgt_pa, GFP_KERNEL);
> > + if (!dom->pgt_va)
> > + return -ENOMEM;
> > +
> > + dom->sdev = sdev;
> > +
> > + sprd_iommu_first_ppn(dom);
> > + sprd_iommu_first_vpn(dom);
> > + sprd_iommu_vpn_range(dom);
> > + sprd_iommu_default_ppn(sdev);
> > + sprd_iommu_hw_en(sdev, true);
> > +
> > + return 0;
> > +}
> > +
> > +static void sprd_iommu_detach_device(struct iommu_domain *domain,
> > + struct device *dev)
> > +{
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > + struct sprd_iommu_device *sdev = dom->sdev;
> > + size_t pgt_size = sprd_iommu_pgt_size(domain);
> > +
> > + dma_free_coherent(sdev->dev, pgt_size, dom->pgt_va, dom->pgt_pa);
>
> sdev may be NULL here.
>
> > + sprd_iommu_hw_en(sdev, false);
> > + dom->sdev = NULL;
> > +}
> > +
> > +static int sprd_iommu_map(struct iommu_domain *domain, unsigned long iova,
> > + phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
> > +{
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > + const struct sprd_iommu_match_data *mdata;
> > + unsigned int page_num = size >> SPRD_IOMMU_PAGE_SHIFT;
> > + unsigned long flags;
> > + unsigned int i;
> > + u32 *pgt_base_iova;
> > + u32 pabase = (u32)paddr;
> > + int map_size = 0;
> > + unsigned long start = domain->geometry.aperture_start;
> > + unsigned long end = domain->geometry.aperture_end;
> > +
> > + if (!dom->sdev) {
> > + pr_err("No sprd_iommu_device attached to the domain\n");
> > + return -EINVAL;
> > + }
> > +
> > + mdata = dom->sdev->mdata;
> > + if (iova < start || (iova + size) > (end + 1)) {
> > + dev_err(dom->sdev->dev, "(iova(0x%lx) + sixe(0x%lx)) are not in the range!\n",
>
> %zx for printing size_t.
>
> > + iova, size);
> > + return -EINVAL;
> > + }
> > +
> > + pgt_base_iova = dom->pgt_va + ((iova - start) >> SPRD_IOMMU_PAGE_SHIFT);
> > +
> > + spin_lock_irqsave(&dom->pgtlock, flags);
> > + for (i = 0; i < page_num; i++) {
> > + pgt_base_iova[i] = pabase >> SPRD_IOMMU_PAGE_SHIFT;
> > + pabase += SPRD_IOMMU_PAGE_SIZE;
> > + map_size += SPRD_IOMMU_PAGE_SIZE;
> > + }
> > + spin_unlock_irqrestore(&dom->pgtlock, flags);
> > +
> > + return map_size == size ? 0 : -EEXIST;
>
> Clearly this can never fail.
>
> > +}
> > +
> > +static size_t sprd_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> > + size_t size, struct iommu_iotlb_gather *iotlb_gather)
> > +{
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > + unsigned long flags;
> > + u32 *pgt_base_iova;
> > + unsigned int page_num = size >> SPRD_IOMMU_PAGE_SHIFT;
> > + unsigned long start = domain->geometry.aperture_start;
> > + unsigned long end = domain->geometry.aperture_end;
> > +
> > + if (iova < start || (iova + size) > (end + 1))
> > + return -EINVAL;
> > +
> > + pgt_base_iova = dom->pgt_va + ((iova - start) >> SPRD_IOMMU_PAGE_SHIFT);
> > +
> > + spin_lock_irqsave(&dom->pgtlock, flags);
> > + memset(pgt_base_iova, 0, page_num * sizeof(u32));
> > + spin_unlock_irqrestore(&dom->pgtlock, flags);
> > +
> > + return 0;
> > +}
> > +
> > +static void sprd_iommu_sync_map(struct iommu_domain *domain)
> > +{
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > + unsigned int reg;
> > +
> > + if (dom->sdev->ver == SPRD_IOMMU_EX)
> > + reg = SPRD_EX_UPDATE;
> > + else
> > + reg = SPRD_VAU_UPDATE;
> > +
> > + /* clear iommu TLB buffer after page table updated */
> > + sprd_iommu_writel(dom->sdev, reg, 0xffffffff);
> > +}
> > +
> > +static void sprd_iommu_sync(struct iommu_domain *domain,
> > + struct iommu_iotlb_gather *iotlb_gather)
> > +{
> > + sprd_iommu_sync_map(domain);
> > +}
> > +
> > +static phys_addr_t sprd_iommu_iova_to_phys(struct iommu_domain *domain,
> > + dma_addr_t iova)
> > +{
> > + struct sprd_iommu_domain *dom = to_sprd_domain(domain);
> > + unsigned long flags;
> > + phys_addr_t pa;
> > + unsigned long start = domain->geometry.aperture_start;
> > + unsigned long end = domain->geometry.aperture_end;
> > +
> > + if (iova < start || iova > end)
> > + pr_err("iova (0x%llx) exceed the vpn range[0x%lx-0x%lx]!\n",
> > + iova, start, end);
> > +
> > + spin_lock_irqsave(&dom->pgtlock, flags);
> > + pa = *(dom->pgt_va + ((iova - start) >> SPRD_IOMMU_PAGE_SHIFT));
> > + pa = pa << SPRD_IOMMU_PAGE_SHIFT;
> > + spin_unlock_irqrestore(&dom->pgtlock, flags);
> > +
> > + return pa;
>
> Don't forget to add back the offset - the input address isn't
> necessarily page-aligned (at least you don't have block mappings to
> worry about as well...)
Ok.
>
> > +}
> > +
> > +static struct iommu_device *sprd_iommu_probe_device(struct device *dev)
> > +{
> > + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > + struct sprd_iommu_device *sdev;
> > +
> > + if (!fwspec || fwspec->ops != &sprd_iommu_ops)
> > + return ERR_PTR(-ENODEV);
> > +
> > + sdev = dev_iommu_priv_get(dev);
> > +
> > + return &sdev->iommu;
> > +}
> > +
> > +static void sprd_iommu_release_device(struct device *dev)
> > +{
> > + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > +
> > + if (!fwspec || fwspec->ops != &sprd_iommu_ops)
> > + return;
> > +
> > + iommu_fwspec_free(dev);
> > +}
> > +
> > +static struct iommu_group *sprd_iommu_device_group(struct device *dev)
> > +{
> > + struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);
> > +
> > + if (!sdev)
> > + return ERR_PTR(-ENODEV);
>
> No need for this check, since iommu_group_get_for_dev() can now only be
> called after you've already handled ->probe_device.
>
> > +
> > + return iommu_group_ref_get(sdev->group);
> > +}
> > +
> > +static int sprd_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
> > +{
> > + struct platform_device *pdev;
> > +
> > + if (!dev_iommu_priv_get(dev)) {
> > + pdev = of_find_device_by_node(args->np);
> > + dev_iommu_priv_set(dev, platform_get_drvdata(pdev));
>
> You leak a reference on pdev->dev here.
Will fix it in the next version.
>
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +
> > +static const struct iommu_ops sprd_iommu_ops = {
> > + .domain_alloc = sprd_iommu_domain_alloc,
> > + .domain_free = sprd_iommu_domain_free,
> > + .attach_dev = sprd_iommu_attach_device,
> > + .detach_dev = sprd_iommu_detach_device,
> > + .map = sprd_iommu_map,
> > + .unmap = sprd_iommu_unmap,
> > + .iotlb_sync_map = sprd_iommu_sync_map,
> > + .iotlb_sync = sprd_iommu_sync,
> > + .iova_to_phys = sprd_iommu_iova_to_phys,
> > + .probe_device = sprd_iommu_probe_device,
> > + .release_device = sprd_iommu_release_device,
> > + .device_group = sprd_iommu_device_group,
> > + .of_xlate = sprd_iommu_of_xlate,
> > + .pgsize_bitmap = ~0UL << SPRD_IOMMU_PAGE_SHIFT,
> > +};
> > +
> > +static const struct sprd_iommu_match_data sprd_iommu_disp = {
> > + .reg_offset = 0x800,
> > +};
> > +
> > +static const struct sprd_iommu_match_data sprd_iommu_jpg = {
> > + .reg_offset = 0x300,
> > +};
>
> Shouldn't those just be part of the base address in the DT to begin
> with? The Rockchip IOMMUs, for example, are all over the place relative
> to the base of whichever media device they're embedded into, and they
> don't care.
I'm considering moving the iommu DT node under into the DT node of the
media device which uses this iommu.
>
> FWIW you can still accommodate your debugging trick without needing an
> excuse for per-instance compatibles in the DT - you could match known
> base addresses at probe to assign your desired IOVA ranges, or
> dynamically assign an IOVA range to each new instance and keep track of
> who got what in debugfs, or wait until probe_device/attach_device and
> inspect the client device itself to see who you belong to.
I considered letting the media devices set IOVA and range, I would
also set a default IOVA start address when allocating the iommu
domain.
>
> > +
> > +static const struct of_device_id sprd_iommu_of_match[] = {
> > + { .compatible = "sprd,iommu-v1-disp",
> > + .data = &sprd_iommu_disp },
> > + { .compatible = "sprd,iommu-v1-jpg",
> > + .data = &sprd_iommu_jpg },
> > + { },
> > +};
> > +MODULE_DEVICE_TABLE(of, sprd_iommu_of_match);
> > +
> > +static int sprd_iommu_clk_enable(struct device *dev)
> > +{
> > + struct clk *eb;
> > +
> > + eb = of_clk_get(dev->of_node, 0);
> > + if (IS_ERR_OR_NULL(eb))
> > + return PTR_ERR(eb);
> > +
> > + clk_prepare_enable(eb);
> > +
> > + return 0;
> > +}
>
> Unless you plan to add significant complexity to this very soon, I don't
> think it really needs a separate helper. Also shouldn't you relinquish
> this clock on probe failure and remove?
I meant to do that since the clock is optional, I added comments in
probe(), I should add comments here.
Also I found I should use clk_get_optional() to get the clock reference.
>
> > +static int sprd_iommu_probe(struct platform_device *pdev)
> > +{
> > + struct sprd_iommu_device *sdev;
> > + struct device *dev = &pdev->dev;
> > + int ret;
> > +
> > + sdev = devm_kzalloc(dev, sizeof(*sdev), GFP_KERNEL);
> > + if (!sdev)
> > + return -ENOMEM;
> > +
> > + sdev->base = devm_platform_ioremap_resource(pdev, 0);
> > + sdev->mdata = device_get_match_data(dev);
> > +
> > + sdev->prot_page_va = dma_alloc_coherent(dev, SPRD_IOMMU_PAGE_SIZE,
> > + &sdev->prot_page_pa, GFP_KERNEL);
> > + if (!sdev->prot_page_va)
> > + return -ENOMEM;
> > +
> > + platform_set_drvdata(pdev, sdev);
> > + sdev->dev = dev;
> > +
> > + /* All the client devices are in the same iommu-group */
> > + sdev->group = iommu_group_alloc();
> > + if (IS_ERR(sdev->group)) {
> > + ret = PTR_ERR(sdev->group);
> > + goto free_page;
> > + }
> > +
> > + ret = iommu_device_sysfs_add(&sdev->iommu, dev, NULL, dev_name(dev));
> > + if (ret)
> > + goto put_group;
> > +
> > + iommu_device_set_ops(&sdev->iommu, &sprd_iommu_ops);
> > + iommu_device_set_fwnode(&sdev->iommu, &dev->of_node->fwnode);
> > +
> > + ret = iommu_device_register(&sdev->iommu);
> > + if (ret)
> > + goto remove_sysfs;
> > +
> > + if (!iommu_present(&platform_bus_type))
> > + bus_set_iommu(&platform_bus_type, &sprd_iommu_ops);
>
> Nit: extra space after the comma.
>
> > +
> > + /* access to some iommus are controlled by gate clock, others are not */
>
> The binding doesn't say you can have clocks...
Forgot to add clock property..
>
> > + sprd_iommu_clk_enable(dev);
> > +
> > + ret = sprd_iommu_get_version(sdev);
> > + if (ret < 0) {
> > + dev_err(dev, "iommu version(%d) is invalid.\n", ret);
> > + goto unregister_iommu;
> > + }
> > + sdev->ver = ret;
> > +
> > + return 0;
> > +
> > +unregister_iommu:
> > + iommu_device_unregister(&sdev->iommu);
> > +remove_sysfs:
> > + iommu_device_sysfs_remove(&sdev->iommu);
> > +put_group:
> > + iommu_group_put(sdev->group);
> > +free_page:
> > + dma_free_coherent(sdev->dev, SPRD_IOMMU_PAGE_SIZE, sdev->prot_page_va, sdev->prot_page_pa);
> > + return ret;
> > +}
> > +
> > +static int sprd_iommu_remove(struct platform_device *pdev)
> > +{
> > + struct sprd_iommu_device *sdev = platform_get_drvdata(pdev);
> > +
> > + dma_free_coherent(sdev->dev, SPRD_IOMMU_PAGE_SIZE, sdev->prot_page_va, sdev->prot_page_pa);
>
> Just to confirm, does the sprd_iommu_hw_en(sdev, false) call from
> sprd_iommu_detach_device() effectively guarantee that no more accesses
> can be made to prot_page after that?
>From what I understand, prot_page is used for the case that if the
virtual address is in the range of iova addresses, but not mapped to a
physical address, then prot_page was provided for accessing, that
would happen only if iommu is enabled.
Back to your question, prot_page wouldn't be accessed any more after
iommu being disabled by calling sprd_iommu_hw_en(sdev, false).
>
> > + iommu_group_put(sdev->group);
> > + sdev->group = NULL;
> > +
> > + bus_set_iommu(&platform_bus_type, NULL);
> > +
> > + platform_set_drvdata(pdev, NULL);
> > + iommu_device_sysfs_remove(&sdev->iommu);
> > + iommu_device_unregister(&sdev->iommu);
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver sprd_iommu_driver = {
> > + .driver = {
> > + .name = "sprd-iommu",
> > + .of_match_table = sprd_iommu_of_match,
>
> You probably want ".suppress_bind_attrs = true" as well.
Thanks for your comments, I will address them in the next version.
Chunyan
>
> Robin.
>
> > +
> > + },
> > + .probe = sprd_iommu_probe,
> > + .remove = sprd_iommu_remove,
> > +};
> > +module_platform_driver(sprd_iommu_driver);
> > +
> > +MODULE_DESCRIPTION("IOMMU driver for Unisoc SoCs");
> > +MODULE_ALIAS("platform:sprd-iommu");
> > +MODULE_LICENSE("GPL v2");
> >
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