arm64 smmu 驱动笔记 （4.19）
设备StreamID：sid
struct iommu_fwspec {
const struct iommu_ops *ops;
struct fwnode_handle *iommu_fwnode;
void *iommu_priv;
unsigned int num_ids;
u32 ids[1]; //ids保存的某device使用的streamID
};通过iommu_fwspec_add_id函数设置：
struct iommu_fwspec {
const struct iommu_ops *ops;
struct fwnode_handle *iommu_fwnode;
void *iommu_priv;
unsigned int num_ids; //和该设备关联的总共ids/streamID
u32 ids[1];//sid内容数组
};
int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids)
{
struct iommu_fwspec *fwspec = dev->iommu_fwspec;
size_t size;
int i;
if (!fwspec)
return -EINVAL;
size = offsetof(struct iommu_fwspec, ids[fwspec->num_ids + num_ids]);
if (size > sizeof(*fwspec)) {
fwspec = krealloc(dev->iommu_fwspec, size, GFP_KERNEL);
if (!fwspec)
return -ENOMEM;
dev->iommu_fwspec = fwspec;
}
for (i = 0; i < num_ids; i++)
fwspec->ids[fwspec->num_ids + i] = ids[i];
fwspec->num_ids += num_ids;
return 0;
}
设置流程dump_stack信息:
[ 79.499624] ===iommu_fwspec_add_ids for dev 0000:0a:00.0 num_ids 1
[ 79.505862] CPU: 29 PID: 1 Comm: swapper/0 Not tainted 4.19.0l+ #20
[ 79.512098] Hardware name: PHYTIUM LTD Phytium S2500/64/Phytium S2500/64, BIOS V2.2 Feb 9 2021
[ 79.520754] Call trace:
[ 79.523192] dump_backtrace+0x0/0x1c0
[ 79.526838] show_stack+0x24/0x30
[ 79.530138] dump_stack+0x9c/0xbc
[ 79.533439] iommu_fwspec_add_ids+0x44/0xd0
[ 79.537602] iort_iommu_xlate+0x144/0x170
[ 79.541592] iort_pci_iommu_init+0x58/0x80
[ 79.545670] pci_for_each_dma_alias+0x44/0x188
[ 79.550093] iort_iommu_configure+0xac/0x1c8
[ 79.554343] acpi_dma_configure+0x68/0xbc
[ 79.558333] pci_dma_configure+0xa8/0xc8
[ 79.562236] dma_configure+0x4c/0x64
[ 79.565795] really_probe+0x98/0x3b8
[ 79.569354] driver_probe_device+0x6c/0x138
[ 79.573516] __driver_attach+0x118/0x150
[ 79.577419] bus_for_each_dev+0x84/0xd8
[ 79.581237] driver_attach+0x30/0x40
[ 79.584795] bus_add_driver+0x20c/0x250
[ 79.588613] driver_register+0x64/0x110
[ 79.592430] __pci_register_driver+0x58/0x68
[ 79.596681] xhci_pci_init+0x58/0x64
[ 79.600240] do_one_initcall+0x68/0x1e4
[ 79.604059] kernel_init_freeable+0x2d0/0x388
[ 79.608396] kernel_init+0x18/0x108
[ 79.611867] ret_from_fork+0x10/0x1c
iort_iommu_configure函数：
//drivers/acpi/arm64/iort.c
const struct iommu_ops *iort_iommu_configure(struct device *dev)
{
struct acpi_iort_node *node, *parent;
const struct iommu_ops *ops;
u32 streamid = 0;
int err = -ENODEV;
/*
* If we already translated the fwspec there
* is nothing left to do, return the iommu_ops.
*/
ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
if (ops)
return ops;
if (dev_is_pci(dev)) { //PCI设备的sid 使用的是BDF号。
struct pci_bus *bus = to_pci_dev(dev)->bus;
struct iort_pci_alias_info info = { .dev = dev };
node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
iort_match_node_callback, &bus->dev);
if (!node)
return NULL;
info.node = node;
//计算sid
err = pci_for_each_dma_alias(to_pci_dev(dev),
iort_pci_iommu_init, &info);
} else {
int i = 0;
node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
iort_match_node_callback, dev);
if (!node)
return NULL;
do {
parent = iort_node_map_platform_id(node, &streamid,
IORT_IOMMU_TYPE,
i++);
if (parent)
err = iort_iommu_xlate(dev, parent, streamid);
} while (parent && !err);
}
/*
* If we have reason to believe the IOMMU driver missed the initial
* add_device callback for dev, replay it to get things in order.
*/
if (!err) {
ops = iort_fwspec_iommu_ops(dev->iommu_fwspec);
err = iort_add_device_replay(ops, dev);
}
/* Ignore all other errors apart from EPROBE_DEFER */
if (err == -EPROBE_DEFER) {
ops = ERR_PTR(err);
} else if (err) {
dev_dbg(dev, "Adding to IOMMU failed: %d\n", err);
ops = NULL;
}
return ops;
}
*/
int pci_for_each_dma_alias(struct pci_dev *pdev,
int (*fn)(struct pci_dev *pdev,
u16 alias, void *data), void *data)
{
.....
struct pci_bus *bus;
int ret;
ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), data);
.....
}
static int iort_pci_iommu_init(struct pci_dev *pdev, u16 alias, void *data)
{
struct iort_pci_alias_info *info = data;
struct acpi_iort_node *parent;
u32 streamid;
parent = iort_node_map_id(info->node, alias, &streamid,
IORT_IOMMU_TYPE);
return iort_iommu_xlate(info->dev, parent, streamid);
}
最终：
static int arm_smmu_iort_xlate(struct device *dev, u32 streamid,
struct fwnode_handle *fwnode,
const struct iommu_ops *ops)
{
int ret = iommu_fwspec_init(dev, fwnode, ops);
if (!ret)
ret = iommu_fwspec_add_ids(dev, &streamid, 1); //添加streamid
return ret;
}arm_smmu_add_device
在drivers/iommu/arm-smmu.c的 arm_smmu_add_device函数中：
#ifdef CONFIG_ARCH_PHYTIUM
#define FWID_READ(id) (((u16)(id) >> 3) | (((id) >> SMR_MASK_SHIFT | 0x7000) << SMR_MASK_SHIFT))
#endif
//默认streamID会使用pci的bdf，但ft2000+ 硬件实现上不同，该值会通过FWID_READ函数进行调整。iommu_fwspec_add_ids加入到fwspec中。因此一个设备会有两个sid。
static int arm_smmu_add_device(struct device *dev)
{
struct arm_smmu_device *smmu;
struct arm_smmu_master_cfg *cfg;
struct iommu_fwspec *fwspec = dev->iommu_fwspec;
int i, ret;
#ifdef CONFIG_ARCH_PHYTIUM
/* FT2000PLUS workaround patch */
if ((read_cpuid_id() & MIDR_CPU_MODEL_MASK) == MIDR_PHYTIUM_FT2000PLUS) {
printk("===arm_smmu_add_device ft2000+ \n");
int num = fwspec->num_ids;
for (i = 0; i < num; i++) {
u32 fwid = FWID_READ(fwspec->ids[i]);
printk("===arm_smmu_add_device ft2000+ ids %llx to fwid %llx \n",fwspec->ids[i],fwid);
iommu_fwspec_add_ids(dev, &fwid, 1);
}
}
#endif
..............
打印一下设备的sid
for (i = 0; i < fwspec->num_ids; i++) {
u16 sid = fwspec->ids[i];
u16 mask = fwspec->ids[i] >> SMR_MASK_SHIFT;
printk("===arm_smmu_add_device for dev %s num_ids %d of %d sid %llx \n",dev_name(dev),fwspec->num_ids,i,sid);
if (sid & ~smmu->streamid_mask) {
dev_err(dev, "stream ID 0x%x out of range for SMMU (0x%x)\n",
sid, smmu->streamid_mask);
goto out_free;
}
if (mask & ~smmu->smr_mask_mask) {
dev_err(dev, "SMR mask 0x%x out of range for SMMU (0x%x)\n",
mask, smmu->smr_mask_mask);
goto out_free;
}
}
...................
ret = arm_smmu_master_alloc_smes(dev); //分配stream mapping entry 表项
}ft2000+日志：0000:04:00.x 都有一个-x80的sid。
[ 11.775255] ===arm_smmu_add_device for dev 0000:41:00.0 num_ids 2 of 0 sid 4100
[ 11.782698] ===arm_smmu_add_device for dev 0000:41:00.0 num_ids 2 of 1 sid 820
[ 12.576919] ===arm_smmu_add_device for dev 0000:03:00.0 num_ids 2 of 0 sid 300
[ 12.576922] ===arm_smmu_add_device for dev 0000:03:00.0 num_ids 2 of 1 sid 60
[ 15.638439] ===arm_smmu_add_device for dev 0000:04:00.0 num_ids 2 of 0 sid 400
[ 15.645802] ===arm_smmu_add_device for dev 0000:04:00.0 num_ids 2 of 1 sid 80
[ 16.494888] ===arm_smmu_add_device for dev 0000:51:00.0 num_ids 2 of 0 sid 5100
[ 16.502947] ===arm_smmu_add_device for dev 0000:51:00.0 num_ids 2 of 1 sid a20
[ 17.105745] ===arm_smmu_add_device for dev 0000:04:00.1 num_ids 2 of 0 sid 401
[ 17.119853] ===arm_smmu_add_device for dev 0000:04:00.1 num_ids 2 of 1 sid 80
[ 18.338789] ===arm_smmu_add_device for dev 0000:04:00.2 num_ids 2 of 0 sid 402
[ 18.346151] ===arm_smmu_add_device for dev 0000:04:00.2 num_ids 2 of 1 sid 80
[ 19.099235] ===arm_smmu_add_device for dev 0000:04:00.3 num_ids 2 of 0 sid 403
[ 19.099237] ===arm_smmu_add_device for dev 0000:04:00.3 num_ids 2 of 1 sid 80
上述中发现一个dev可能有多个sid，如iommu_fwspec_add_ids函数关联了多个sid的话，最终往iommu_fwspec 中填充sid数组值。
在arm_smmu_add_device函数中建立一个设备下的sid和其它数据的关系：
static int arm_smmu_add_device(struct device *dev)
{
#ifdef CONFIG_ARCH_PHYTIUM
#define FWID_READ(id) (((u16)(id) >> 3) | (((id) >> SMR_MASK_SHIFT | 0x7000) << SMR_MASK_SHIFT))
/* FT2000PLUS workaround patch */
if ((read_cpuid_id() & MIDR_CPU_MODEL_MASK) == MIDR_PHYTIUM_FT2000PLUS) {
int num = fwspec->num_ids;
for (i = 0; i < num; i++) {
u32 fwid = FWID_READ(fwspec->ids[i]);
iommu_fwspec_add_ids(dev, &fwid, 1); //这里对2000+进行特殊处理，再一次添加了处理后的sid值，应该是2000+处理器的smmu识别sid的方式不一样，
}
}
#endif
ret = -EINVAL;
for (i = 0; i < fwspec->num_ids; i++) {
u16 sid = fwspec->ids[i];
u16 mask = fwspec->ids[i] >> SMR_MASK_SHIFT;
if (sid & ~smmu->streamid_mask) {
dev_err(dev, "stream ID 0x%x out of range for SMMU (0x%x)\n",
sid, smmu->streamid_mask);
goto out_free;
}
if (mask & ~smmu->smr_mask_mask) {
dev_err(dev, "SMR mask 0x%x out of range for SMMU (0x%x)\n",
mask, smmu->smr_mask_mask);
goto out_free;
}
}
ret = -ENOMEM;
//cfg的smendx数组大小刚好和fwspec的num_ids一致，后面要保存数据。
cfg = kzalloc(offsetof(struct arm_smmu_master_cfg, smendx[i]),
GFP_KERNEL);
if (!cfg)
goto out_free;
cfg->smmu = smmu;
fwspec->iommu_priv = cfg;
while (i--)
cfg->smendx[i] = INVALID_SMENDX;
ret = arm_smmu_master_alloc_smes(dev);
}arm_smmu_attach_dev函数：
arm_smmu_init_domain_context初始化domain，是arm_smmu_add_device一路调用到arm_smmu_attach_dev：
static int arm_smmu_init_domain_context(struct iommu_domain *domain,
struct arm_smmu_device *smmu)
{
............
struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
ret = __arm_smmu_alloc_bitmap(smmu->context_map, start,
smmu->num_context_banks);
cfg->cbndx = ret; //将上述获取的全局唯一context bank 编号 保存在cfg->cbndx
arm_smmu_init_context_bank(smmu_domain, &pgtbl_cfg); //设置好cb等参数。其中包括lape获取的页表等内容。
arm_smmu_write_context_bank(smmu, cfg->cbndx); //编号作为参数
............
}
static void arm_smmu_write_context_bank(struct arm_smmu_device *smmu, int idx)
{
............
cb_base = ARM_SMMU_CB(smmu, idx); //根据编号获取cb_base地址
下面是一些写寄存器的操作
/* TTBRs */
if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
writel_relaxed(cfg->asid, cb_base + ARM_SMMU_CB_CONTEXTIDR);
writel_relaxed(cb->ttbr[0], cb_base + ARM_SMMU_CB_TTBR0);
writel_relaxed(cb->ttbr[1], cb_base + ARM_SMMU_CB_TTBR1);
} else {
writeq_relaxed(cb->ttbr[0], cb_base + ARM_SMMU_CB_TTBR0); //将ttbr[0]写入，其中保存的是页表的pgd基地址。
if (stage1)
writeq_relaxed(cb->ttbr[1], cb_base + ARM_SMMU_CB_TTBR1);
}
............
}[ 78.770289] ===arm_smmu_init_domain_context for dev arm-smmu.0.auto domain ffff8139415a1b50 smmu ffff834941ef0018 smmu_doamin->stage 0 fmt 2 cfg->cbndx 0
[ 78.784048] CPU: 28 PID: 1 Comm: swapper/0 Not tainted 4.19.0l+ #40
[ 78.790284] Hardware name: PHYTIUM LTD Phytium S2500/64/Phytium S2500/64, BIOS V2.2 Feb 9 2021
[ 78.798938] Call trace:
[ 78.801373] dump_backtrace+0x0/0x1c0
[ 78.805017] show_stack+0x24/0x30
[ 78.808316] dump_stack+0x9c/0xbc
[ 78.811615] arm_smmu_attach_dev+0x44c/0x788
[ 78.815864] __iommu_attach_device+0x54/0xf8
[ 78.820113] iommu_group_add_device+0x17c/0x478
[ 78.824621] iommu_group_get_for_dev+0x74/0x178
[ 78.829129] arm_smmu_add_device+0x218/0x6b8
[ 78.833379] iort_iommu_configure+0x144/0x1c8
[ 78.837715] acpi_dma_configure+0x68/0xbc
[ 78.841705] pci_dma_configure+0xa8/0xc8
[ 78.845608] dma_configure+0x4c/0x64
[ 78.849166] really_probe+0x98/0x3b8
[ 78.852725] driver_probe_device+0x6c/0x138
[ 78.856887] __driver_attach+0x118/0x150
[ 78.860790] bus_for_each_dev+0x84/0xd8
[ 78.864608] driver_attach+0x30/0x40
[ 78.868166] bus_add_driver+0x20c/0x250
[ 78.871984] driver_register+0x64/0x110
[ 78.875802] __pci_register_driver+0x58/0x68
[ 78.880051] ahci_pci_driver_init+0x28/0x30
[ 78.884213] do_one_initcall+0x68/0x1e4
[ 78.888031] kernel_init_freeable+0x2d0/0x388
[ 78.892367] kernel_init+0x18/0x108
[ 78.895839] ret_from_fork+0x10/0x1c
设备创建group和doamin流程
device：加组流程
really_probe
dma_configure
pci_dma_configure
acpi_dma_configure
iort_iommu_configure
arm_smmu_add_device
arm_smmu_master_alloc_smes
iommu_group_get_for_dev
arm_smmu_device_group //创建iommu_group
group->default_domain = dom; //创建domain
group->domain = dom;
iommu_group_add_device //将deive加入到group链表，将iommu_grouop 赋值dev->iommu_group指针
__iommu_attach_device
arm_smmu_attach_dev
for_each_cfg_sme：smmu->s2crs[idx].group = group; //循环将该device下的第idxg个s2crs数组分配group
arm_smmu_device_group
pci_device_group
alloc_group
generic_device_group
关联smmu下的SMMU_SMRn寄存器。其中写入streamID。
相关寄存器参考：(66条消息) Smmu硬件寄存器—V2_一墨一飞花的博客-CSDN博客_smmu context bank
SMMU_SMRn
streamID匹配寄存器。
EXMASK, bits[31:16] 屏蔽无关位，如果EXMASK[i]==1，则EXID[i]被忽略；
相反，EXMASK[i]==0，则EXID[i]有效，用于匹配
EXID, bits[15:0] 用于匹配的streamID
static int arm_smmu_master_alloc_smes(struct device *dev)
{
struct iommu_fwspec *fwspec = dev->iommu_fwspec;
struct arm_smmu_master_cfg *cfg = fwspec->iommu_priv;
struct arm_smmu_device *smmu = cfg->smmu;
struct arm_smmu_smr *smrs = smmu->smrs;
struct iommu_group *group;
int i, idx, ret;
mutex_lock(&smmu->stream_map_mutex);
/* Figure out a viable stream map entry allocation */
for_each_cfg_sme(fwspec, i, idx) {
u16 sid = fwspec->ids[i];
u16 mask = fwspec->ids[i] >> SMR_MASK_SHIFT;
if (idx != INVALID_SMENDX) {
ret = -EEXIST;
goto out_err;
}
ret = arm_smmu_find_sme(smmu, sid, mask); //分配一个smmu下唯一的idx给当前设备的arm_smmu_master_cfg ,如果sid一致，则返回同样的idx。这个在ft2000+上就是这种情况，bus_dev_fn忽略fn则会导致很多设备相同。
if (ret < 0)
goto out_err;
idx = ret;
if (smrs && smmu->s2crs[idx].count == 0) {
smrs[idx].id = sid; //将streamid保存在全局smrs数组下，后续写入寄存器中，一个设备有多个sid的情况下也会分配多个全局唯一的idx。
smrs[idx].mask = mask;
smrs[idx].valid = true;
}
smmu->s2crs[idx].count++;
cfg->smendx[i] = (s16)idx; //设置当前设备arm_smmu_master_cfg 数组smendx为smmu全局分配的idx值。
}
group = iommu_group_get_for_dev(dev);
if (!group)
group = ERR_PTR(-ENOMEM);
if (IS_ERR(group)) {
ret = PTR_ERR(group);
goto out_err;
}
iommu_group_put(group);
/* It worked! Now, poke the actual hardware */
for_each_cfg_sme(fwspec, i, idx) {
arm_smmu_write_sme(smmu, idx); //将smrs下的sid写入寄存器中。根据idx来定位寄存器地址。
smmu->s2crs[idx].group = group;
}
mutex_unlock(&smmu->stream_map_mutex);
return 0;
out_err:
while (i--) {
arm_smmu_free_sme(smmu, cfg->smendx[i]);
cfg->smendx[i] = INVALID_SMENDX;
}
mutex_unlock(&smmu->stream_map_mutex);
return ret;
}关联smmu下的s2cr寄存器。
static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain,
struct iommu_fwspec *fwspec)
{
struct arm_smmu_device *smmu = smmu_domain->smmu;
struct arm_smmu_s2cr *s2cr = smmu->s2crs;
u8 cbndx = smmu_domain->cfg.cbndx; //init_context_bank 中分配的，从bitmap中查找的唯一编号，参考arm_smmu_init_domain_context中分配cfg->cbndx的过程。
enum arm_smmu_s2cr_type type;
int i, idx;
if (smmu_domain->stage == ARM_SMMU_DOMAIN_BYPASS)
type = S2CR_TYPE_BYPASS;
else
type = S2CR_TYPE_TRANS;
for_each_cfg_sme(fwspec, i, idx) {
if (type == s2cr[idx].type && cbndx == s2cr[idx].cbndx)
continue;
s2cr[idx].type = type;
s2cr[idx].privcfg = S2CR_PRIVCFG_DEFAULT;
s2cr[idx].cbndx = cbndx;
arm_smmu_write_s2cr(smmu, idx); //根据设备在全局的idx号，定位到s2cr寄存器地址。
}
return 0;
}相关写寄存器的函数：通过idx关联。
//写入streamID。可以推断idx值
static void arm_smmu_write_smr(struct arm_smmu_device *smmu, int idx)
{
struct arm_smmu_smr *smr = smmu->smrs + idx;
u32 reg = smr->id << SMR_ID_SHIFT | smr->mask << SMR_MASK_SHIFT;
if (!(smmu->features & ARM_SMMU_FEAT_EXIDS) && smr->valid)
reg |= SMR_VALID;
writel_relaxed(reg, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_SMR(idx));
}
//根据idx 找到s2cr寄存器，可以找到cbndx值，该值可以定位到io-pgtable页表的pgd地址。
static void arm_smmu_write_s2cr(struct arm_smmu_device *smmu, int idx)
{
struct arm_smmu_s2cr *s2cr = smmu->s2crs + idx;
u32 reg = (s2cr->type & S2CR_TYPE_MASK) << S2CR_TYPE_SHIFT | //16-17bit为TYPE位
(s2cr->cbndx & S2CR_CBNDX_MASK) << S2CR_CBNDX_SHIFT | //0-7bit为CBNDX位。
(s2cr->privcfg & S2CR_PRIVCFG_MASK) << S2CR_PRIVCFG_SHIFT;
if (smmu->features & ARM_SMMU_FEAT_EXIDS && smmu->smrs &&
smmu->smrs[idx].valid)
reg |= S2CR_EXIDVALID;
writel_relaxed(reg, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_S2CR(idx));
}
static void arm_smmu_write_sme(struct arm_smmu_device *smmu, int idx)
{
arm_smmu_write_s2cr(smmu, idx);
if (smmu->smrs)
arm_smmu_write_smr(smmu, idx);
}arm_smmu_device_group：
static struct iommu_group *arm_smmu_device_group(struct device *dev)
{
struct iommu_fwspec *fwspec = dev->iommu_fwspec;
struct arm_smmu_device *smmu = fwspec_smmu(fwspec);
struct iommu_group *group = NULL;
int i, idx;
for_each_cfg_sme(fwspec, i, idx) {
if (group && smmu->s2crs[idx].group &&
group != smmu->s2crs[idx].group)
return ERR_PTR(-EINVAL);
printk("===arm_smmu_deivce_group for %s idx %d group %llx \n",dev_name(dev),idx,group);
group = smmu->s2crs[idx].group; //对于ft2000+，由于idx存在一致，因此会分在一个组。
}
printk("==arm_smmu_device_group=== is_pci %d group = %llx name %s \n",dev_is_pci(dev),group,dev_name(dev));
if (group)
return iommu_group_ref_get(group);
printk("group is empty \n");
if (dev_is_pci(dev))
group = pci_device_group(dev);
else
group = generic_device_group(dev);
return group;
}
arm_smmu_attach_dev->
arm_smmu_domain_add_master
{
....
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
struct arm_smmu_master_cfg *cfg = dev_iommu_priv_get(dev);
arm_smmu_domain_add_master(smmu_domain, cfg, fwspec);
.....
}
/*
配置设备下不同idx组寄存器，其中cbndx使用的是domain唯一的值。
不同设备如果使用同一个domain。则根据唯一的cbndx值(arm_smmu_init_domain_context中分配)
因此设备的dma发送sid找到smr的idx组。对应s2cr中查找cbndx。进而找到ttbr ？
*/
static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain, //设备归属的domain
struct arm_smmu_master_cfg *cfg, //dev下的
struct iommu_fwspec *fwspec) //dev下的
{
struct arm_smmu_device *smmu = smmu_domain->smmu;
struct arm_smmu_s2cr *s2cr = smmu->s2crs;
u8 cbndx = smmu_domain->cfg.cbndx; //一个domain唯一的cbndx。
enum arm_smmu_s2cr_type type;
int i, idx;
if (smmu_domain->stage == ARM_SMMU_DOMAIN_BYPASS)
type = S2CR_TYPE_BYPASS;
else
type = S2CR_TYPE_TRANS;
for_each_cfg_sme(cfg, fwspec, i, idx) {
if (type == s2cr[idx].type && cbndx == s2cr[idx].cbndx)
continue;
s2cr[idx].type = type;
s2cr[idx].privcfg = S2CR_PRIVCFG_DEFAULT;
s2cr[idx].cbndx = cbndx;
arm_smmu_write_s2cr(smmu, idx); //写入第idx组s2cr寄存器
}
return 0;
}
StreamID写入smmu寄存器：
arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
arm_smmu_init_domain_context(domain, smmu);
arm_smmu_init_context_bank(smmu_domain, &pgtbl_cfg);
arm_smmu_write_context_bank(smmu, cfg->cbndx);
地址映射使用io_pgtable_ops
//drivers/iommu/io-pgtable.h
struct io_pgtable_ops {
int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
phys_addr_t paddr, size_t size, int prot);
size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
size_t size);
phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,
unsigned long iova);
};
iommu_ops的map函数arm_smmu_map
static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot)
{
struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
if (!ops)
return -ENODEV;
return ops->map(ops, iova, paddr, size, prot);
}
arm_smmu_init_domain_context中对domain进行初始化的时候分配io_pgtable_ops:
static int arm_smmu_init_domain_context(struct iommu_domain *domain,
struct arm_smmu_device *smmu)
{
................
pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
................
}
//drivers/iommu/io-pgtable.c
static const struct io_pgtable_init_fns *
io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
#ifdef CONFIG_IOMMU_IO_PGTABLE_LPAE
[ARM_32_LPAE_S1] = &io_pgtable_arm_32_lpae_s1_init_fns,
[ARM_32_LPAE_S2] = &io_pgtable_arm_32_lpae_s2_init_fns,
[ARM_64_LPAE_S1] = &io_pgtable_arm_64_lpae_s1_init_fns,
[ARM_64_LPAE_S2] = &io_pgtable_arm_64_lpae_s2_init_fns,
#endif
#ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S
[ARM_V7S] = &io_pgtable_arm_v7s_init_fns,
#endif
};
struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
struct io_pgtable_cfg *cfg,
void *cookie)
{
struct io_pgtable *iop;
const struct io_pgtable_init_fns *fns;
if (fmt >= IO_PGTABLE_NUM_FMTS)
return NULL;
fns = io_pgtable_init_table[fmt];
if (!fns)
return NULL;
iop = fns->alloc(cfg, cookie);
if (!iop)
return NULL;
iop->fmt = fmt;
iop->cookie = cookie;
iop->cfg = *cfg;
return &iop->ops;
}
io_pgtable_arm_64_lpae_s1_init_fns: driver/iommu/io-pgtable-arm.c
struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns = {
.alloc = arm_64_lpae_alloc_pgtable_s1,
.free = arm_lpae_free_pgtable,
};
static struct io_pgtable *
arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
{
..................
struct arm_lpae_io_pgtable *data;
data = arm_lpae_alloc_pgtable(cfg); //分配
data->pgd = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
...................
}
static struct arm_lpae_io_pgtable *
arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
{
unsigned long va_bits, pgd_bits;
struct arm_lpae_io_pgtable *data;
。。。。。。。。。。。
data = kmalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return NULL;
data->pg_shift = __ffs(cfg->pgsize_bitmap);
data->bits_per_level = data->pg_shift - ilog2(sizeof(arm_lpae_iopte));
va_bits = cfg->ias - data->pg_shift;
data->levels = DIV_ROUND_UP(va_bits, data->bits_per_level);
/* Calculate the actual size of our pgd (without concatenation) */
pgd_bits = va_bits - (data->bits_per_level * (data->levels - 1));
data->pgd_size = 1UL << (pgd_bits + ilog2(sizeof(arm_lpae_iopte)));
data->iop.ops = (struct io_pgtable_ops) {
.map = arm_lpae_map, //map函数
.unmap = arm_lpae_unmap,
.iova_to_phys = arm_lpae_iova_to_phys,
};
return data;
}
案例：
ft2000+/5.10内核
分组树：
[root@localhost ~]# tree /sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/
├── 0
│ ├── devices
│ │ └── 0000:41:00.0 -> ../../../../devices/pci0000:40/0000:40:00.0/0000:41:00.0
│ ├── reserved_regions
│ └── type
├── 1
│ ├── devices
│ │ └── 0000:03:00.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:01.0/0000:03:00.0
│ ├── reserved_regions
│ └── type
├── 10
│ ├── devices
│ │ └── 0000:40:00.0 -> ../../../../devices/pci0000:40/0000:40:00.0
│ ├── reserved_regions
│ └── type
├── 11
│ ├── devices
│ │ └── 0000:50:00.0 -> ../../../../devices/pci0000:50/0000:50:00.0
│ ├── reserved_regions
│ └── type
├── 12
│ ├── devices
│ │ └── 0000:70:00.0 -> ../../../../devices/pci0000:70/0000:70:00.0
│ ├── reserved_regions
│ └── type
├── 13
│ ├── devices
│ │ ├── 0000:04:00.1 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:02.0/0000:04:00.1
│ │ ├── 0000:04:00.2 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:02.0/0000:04:00.2
│ │ └── 0000:04:00.3 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:02.0/0000:04:00.3
│ ├── reserved_regions
│ └── type
├── 14
│ ├── devices
│ │ └── 0000:21:00.0 -> ../../../../devices/pci0000:20/0000:20:00.0/0000:21:00.0
│ ├── reserved_regions
│ └── type
├── 2
│ ├── devices
│ │ └── 0000:00:00.0 -> ../../../../devices/pci0000:00/0000:00:00.0
│ ├── reserved_regions
│ └── type
├── 3
│ ├── devices
│ │ └── 0000:01:00.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0
│ ├── reserved_regions
│ └── type
├── 4
│ ├── devices
│ │ └── 0000:02:01.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:01.0
│ ├── reserved_regions
│ └── type
├── 5
│ ├── devices
│ │ └── 0000:02:02.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:02.0
│ ├── reserved_regions
│ └── type
├── 6
│ ├── devices
│ │ └── 0000:02:04.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:04.0
│ ├── reserved_regions
│ └── type
├── 7
│ ├── devices
│ │ └── 0000:02:05.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:05.0
│ ├── reserved_regions
│ └── type
├── 8
│ ├── devices
│ │ └── 0000:02:06.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:06.0
│ ├── reserved_regions
│ └── type
└── 9
├── devices
│ ├── 0000:04:00.0 -> ../../../../devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:02.0/0000:04:00.0
│ └── 0000:20:00.0 -> ../../../../devices/pci0000:20/0000:20:00.0
├── reserved_regions
└── type
48 directories, 30 files
设备下最终sid：看下上述9组。包含04:00.0和20：00.0。 看下面的日志：恰好这两个共同的0x400的sid；
[ 10.503563] ===arm_smmu_add_device dev 0000:41:00.0 num_ids 4 of 0 sid 4100
[ 10.510581] ===arm_smmu_add_device dev 0000:41:00.0 num_ids 4 of 1 sid 4101
[ 10.517598] ===arm_smmu_add_device dev 0000:41:00.0 num_ids 4 of 2 sid 820
[ 10.524522] ===arm_smmu_add_device dev 0000:41:00.0 num_ids 4 of 3 sid 820
[ 10.677266] ===arm_smmu_add_device dev 0000:03:00.0 num_ids 2 of 0 sid 300
[ 10.684191] ===arm_smmu_add_device dev 0000:03:00.0 num_ids 2 of 1 sid 60
[ 11.108133] ===arm_smmu_add_device dev 0000:00:00.0 num_ids 2 of 0 sid 0
[ 11.121369] ===arm_smmu_add_device dev 0000:00:00.0 num_ids 2 of 1 sid 0
[ 11.155433] ===arm_smmu_add_device dev 0000:01:00.0 num_ids 2 of 0 sid 100
[ 11.162367] ===arm_smmu_add_device dev 0000:01:00.0 num_ids 2 of 1 sid 20
[ 11.215796] ===arm_smmu_add_device dev 0000:02:01.0 num_ids 2 of 0 sid 208
[ 11.215799] ===arm_smmu_add_device dev 0000:02:01.0 num_ids 2 of 1 sid 41
[ 11.268019] ===arm_smmu_add_device dev 0000:02:02.0 num_ids 2 of 0 sid 210
[ 11.283765] ===arm_smmu_add_device dev 0000:02:02.0 num_ids 2 of 1 sid 42
[ 11.387949] ===arm_smmu_add_device dev 0000:02:04.0 num_ids 2 of 0 sid 220
[ 11.387950] ===arm_smmu_add_device dev 0000:02:04.0 num_ids 2 of 1 sid 44
[ 11.442892] ===arm_smmu_add_device dev 0000:02:05.0 num_ids 2 of 0 sid 228
[ 11.449820] ===arm_smmu_add_device dev 0000:02:05.0 num_ids 2 of 1 sid 45
[ 11.484502] ===arm_smmu_add_device dev 0000:02:06.0 num_ids 2 of 0 sid 230
[ 11.491435] ===arm_smmu_add_device dev 0000:02:06.0 num_ids 2 of 1 sid 46
[ 11.526207] ===arm_smmu_add_device dev 0000:20:00.0 num_ids 2 of 0 sid 2000
[ 11.533218] ===arm_smmu_add_device dev 0000:20:00.0 num_ids 2 of 1 sid 400 //0x400
[ 11.568096] ===arm_smmu_add_device dev 0000:40:00.0 num_ids 2 of 0 sid 4000
[ 11.575107] ===arm_smmu_add_device dev 0000:40:00.0 num_ids 2 of 1 sid 800
[ 11.610065] ===arm_smmu_add_device dev 0000:50:00.0 num_ids 2 of 0 sid 5000
[ 11.617080] ===arm_smmu_add_device dev 0000:50:00.0 num_ids 2 of 1 sid a00
[ 11.652088] ===arm_smmu_add_device dev 0000:70:00.0 num_ids 2 of 0 sid 7000
[ 11.665674] ===arm_smmu_add_device dev 0000:70:00.0 num_ids 2 of 1 sid e00
[ 13.530809] ===arm_smmu_add_device dev 0000:04:00.0 num_ids 2 of 0 sid 400 //x0400
[ 13.537743] ===arm_smmu_add_device dev 0000:04:00.0 num_ids 2 of 1 sid 80
[ 13.848325] ===arm_smmu_add_device dev 0000:04:00.1 num_ids 2 of 0 sid 401
[ 13.855250] ===arm_smmu_add_device dev 0000:04:00.1 num_ids 2 of 1 sid 80
[ 14.171899] ===arm_smmu_add_device dev 0000:04:00.2 num_ids 2 of 0 sid 402
[ 14.178831] ===arm_smmu_add_device dev 0000:04:00.2 num_ids 2 of 1 sid 80
[ 14.489847] ===arm_smmu_add_device dev 0000:04:00.3 num_ids 2 of 0 sid 403
[ 14.496779] ===arm_smmu_add_device dev 0000:04:00.3 num_ids 2 of 1 sid 80
[ 21.292421] ===arm_smmu_add_device dev 0000:21:00.0 num_ids 2 of 0 sid 2100
[ 21.299443] ===arm_smmu_add_device dev 0000:21:00.0 num_ids 2 of 1 sid 420