2023-12-11 08:53:30

by Jianjun Wang (王建军)

[permalink] [raw]
Subject: [PATCH v2 0/3] PCI: mediatek: Allocate MSI address with dmam_alloc_coherent()

These series of patches change the allocation of MSI address on MediaTek
platform, which uses dmam_alloc_coherent() to allocate the MSI address.

Changes in v2:
1. Add a separate patch for pcie-mediatek-gen3.c to prevent break the
probe flow when MSI init fails.
2. Change the location of allocate the MSI address to prevent break the
probe flow.

Jianjun Wang (3):
PCI: mediatek: Allocate MSI address with dmam_alloc_coherent()
PCI: mediatek-gen3: Do not break probe flow when MSI init fails
PCI: mediatek-gen3: Allocate MSI address with dmam_alloc_coherent()

drivers/pci/controller/pcie-mediatek-gen3.c | 126 +++++++++++---------
drivers/pci/controller/pcie-mediatek.c | 24 ++--
2 files changed, 83 insertions(+), 67 deletions(-)

--
2.18.0


2023-12-11 08:53:32

by Jianjun Wang (王建军)

[permalink] [raw]
Subject: [PATCH v2 3/3] PCI: mediatek-gen3: Allocate MSI address with dmam_alloc_coherent()

Use dmam_alloc_coherent() to allocate the MSI address, instead of using
static physical address.

Signed-off-by: Jianjun Wang <[email protected]>
---
drivers/pci/controller/pcie-mediatek-gen3.c | 72 ++++++++++++---------
1 file changed, 41 insertions(+), 31 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index c6a6876d233a..7cfd7ef9ad95 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -120,7 +120,6 @@ struct mtk_msi_set {
* struct mtk_gen3_pcie - PCIe port information
* @dev: pointer to PCIe device
* @base: IO mapped register base
- * @reg_base: physical register base
* @mac_reset: MAC reset control
* @phy_reset: PHY reset control
* @phy: PHY controller block
@@ -139,7 +138,6 @@ struct mtk_msi_set {
struct mtk_gen3_pcie {
struct device *dev;
void __iomem *base;
- phys_addr_t reg_base;
struct reset_control *mac_reset;
struct reset_control *phy_reset;
struct phy *phy;
@@ -309,24 +307,8 @@ static int mtk_pcie_set_trans_table(struct mtk_gen3_pcie *pcie,

static void mtk_pcie_enable_msi(struct mtk_gen3_pcie *pcie)
{
- int i;
u32 val;

- for (i = 0; i < PCIE_MSI_SET_NUM; i++) {
- struct mtk_msi_set *msi_set = &pcie->msi_sets[i];
-
- msi_set->base = pcie->base + PCIE_MSI_SET_BASE_REG +
- i * PCIE_MSI_SET_OFFSET;
- msi_set->msg_addr = pcie->reg_base + PCIE_MSI_SET_BASE_REG +
- i * PCIE_MSI_SET_OFFSET;
-
- /* Configure the MSI capture address */
- writel_relaxed(lower_32_bits(msi_set->msg_addr), msi_set->base);
- writel_relaxed(upper_32_bits(msi_set->msg_addr),
- pcie->base + PCIE_MSI_SET_ADDR_HI_BASE +
- i * PCIE_MSI_SET_ADDR_HI_OFFSET);
- }
-
val = readl_relaxed(pcie->base + PCIE_MSI_SET_ENABLE_REG);
val |= PCIE_MSI_SET_ENABLE;
writel_relaxed(val, pcie->base + PCIE_MSI_SET_ENABLE_REG);
@@ -653,6 +635,29 @@ static int mtk_pcie_init_msi(struct mtk_gen3_pcie *pcie)
{
struct device *dev = pcie->dev;
struct device_node *node = dev->of_node;
+ struct mtk_msi_set *msi_set;
+ void *msg_vaddr[PCIE_MSI_SET_NUM];
+ int i, j, ret = -ENODEV;
+
+ for (i = 0; i < PCIE_MSI_SET_NUM; i++) {
+ msi_set = &pcie->msi_sets[i];
+
+ msi_set->base = pcie->base + PCIE_MSI_SET_BASE_REG +
+ i * PCIE_MSI_SET_OFFSET;
+
+ msg_vaddr[i] = dmam_alloc_coherent(dev, sizeof(dma_addr_t),
+ &msi_set->msg_addr, GFP_KERNEL);
+ if (!msg_vaddr[i]) {
+ dev_err(dev, "failed to alloc and map MSI address for set %d\n", i);
+ ret = -ENOMEM;
+ goto err_alloc_addr;
+ }
+
+ /* Configure the MSI capture address */
+ writel_relaxed(lower_32_bits(msi_set->msg_addr), msi_set->base);
+ writel_relaxed(upper_32_bits(msi_set->msg_addr), pcie->base +
+ PCIE_MSI_SET_ADDR_HI_BASE + i * PCIE_MSI_SET_ADDR_HI_OFFSET);
+ }

mutex_init(&pcie->lock);

@@ -660,18 +665,24 @@ static int mtk_pcie_init_msi(struct mtk_gen3_pcie *pcie)
&mtk_msi_bottom_domain_ops, pcie);
if (!pcie->msi_bottom_domain) {
dev_err(dev, "failed to create MSI bottom domain\n");
- return -ENODEV;
+ goto err_alloc_addr;
}

pcie->msi_domain = pci_msi_create_irq_domain(dev->fwnode, &mtk_msi_domain_info,
pcie->msi_bottom_domain);
- if (!pcie->msi_domain) {
- dev_err(dev, "failed to create MSI domain\n");
- irq_domain_remove(pcie->msi_bottom_domain);
- return -ENODEV;
+ if (pcie->msi_domain)
+ return 0;
+
+ dev_err(dev, "failed to create MSI domain\n");
+ irq_domain_remove(pcie->msi_bottom_domain);
+
+err_alloc_addr:
+ for (j = 0; j < i; j++) {
+ msi_set = &pcie->msi_sets[j];
+ dmam_free_coherent(dev, sizeof(dma_addr_t), msg_vaddr[j], msi_set->msg_addr);
}

- return 0;
+ return ret;
}

static int mtk_pcie_init_intx(struct mtk_gen3_pcie *pcie)
@@ -789,20 +800,14 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
{
struct device *dev = pcie->dev;
struct platform_device *pdev = to_platform_device(dev);
- struct resource *regs;
int ret;

- regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, "pcie-mac");
- if (!regs)
- return -EINVAL;
- pcie->base = devm_ioremap_resource(dev, regs);
+ pcie->base = devm_platform_ioremap_resource_byname(pdev, "pcie-mac");
if (IS_ERR(pcie->base)) {
dev_err(dev, "failed to map register base\n");
return PTR_ERR(pcie->base);
}

- pcie->reg_base = regs->start;
-
pcie->phy_reset = devm_reset_control_get_optional_exclusive(dev, "phy");
if (IS_ERR(pcie->phy_reset)) {
ret = PTR_ERR(pcie->phy_reset);
@@ -1013,6 +1018,11 @@ static void mtk_pcie_irq_restore(struct mtk_gen3_pcie *pcie)
for (i = 0; i < PCIE_MSI_SET_NUM; i++) {
struct mtk_msi_set *msi_set = &pcie->msi_sets[i];

+ /* Configure the MSI capture address */
+ writel_relaxed(lower_32_bits(msi_set->msg_addr), msi_set->base);
+ writel_relaxed(upper_32_bits(msi_set->msg_addr), pcie->base +
+ PCIE_MSI_SET_ADDR_HI_BASE + i * PCIE_MSI_SET_ADDR_HI_OFFSET);
+
writel_relaxed(msi_set->saved_irq_state,
msi_set->base + PCIE_MSI_SET_ENABLE_OFFSET);
}
--
2.18.0

2023-12-11 08:53:37

by Jianjun Wang (王建军)

[permalink] [raw]
Subject: [PATCH v2 1/3] PCI: mediatek: Allocate MSI address with dmam_alloc_coherent()

Use dmam_alloc_coherent() to allocate the MSI address, instead of using
virt_to_phys().

Signed-off-by: Jianjun Wang <[email protected]>
---
drivers/pci/controller/pcie-mediatek.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index 66a8f73296fc..2fb9e44369f8 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -178,6 +178,7 @@ struct mtk_pcie_soc {
* @phy: pointer to PHY control block
* @slot: port slot
* @irq: GIC irq
+ * @msg_addr: MSI message address
* @irq_domain: legacy INTx IRQ domain
* @inner_domain: inner IRQ domain
* @msi_domain: MSI IRQ domain
@@ -198,6 +199,7 @@ struct mtk_pcie_port {
struct phy *phy;
u32 slot;
int irq;
+ dma_addr_t msg_addr;
struct irq_domain *irq_domain;
struct irq_domain *inner_domain;
struct irq_domain *msi_domain;
@@ -394,12 +396,10 @@ static struct pci_ops mtk_pcie_ops_v2 = {
static void mtk_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
- phys_addr_t addr;

/* MT2712/MT7622 only support 32-bit MSI addresses */
- addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
msg->address_hi = 0;
- msg->address_lo = lower_32_bits(addr);
+ msg->address_lo = lower_32_bits(port->msg_addr);

msg->data = data->hwirq;

@@ -494,6 +494,14 @@ static struct msi_domain_info mtk_msi_domain_info = {
static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
{
struct fwnode_handle *fwnode = of_node_to_fwnode(port->pcie->dev->of_node);
+ void *msi_vaddr;
+
+ msi_vaddr = dmam_alloc_coherent(port->pcie->dev, sizeof(dma_addr_t), &port->msg_addr,
+ GFP_KERNEL);
+ if (!msi_vaddr) {
+ dev_err(port->pcie->dev, "failed to alloc and map MSI address\n");
+ return -ENOMEM;
+ }

mutex_init(&port->lock);

@@ -501,6 +509,7 @@ static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
&msi_domain_ops, port);
if (!port->inner_domain) {
dev_err(port->pcie->dev, "failed to create IRQ domain\n");
+ dmam_free_coherent(port->pcie->dev, sizeof(dma_addr_t), msi_vaddr, port->msg_addr);
return -ENOMEM;
}

@@ -508,6 +517,7 @@ static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
port->inner_domain);
if (!port->msi_domain) {
dev_err(port->pcie->dev, "failed to create MSI domain\n");
+ dmam_free_coherent(port->pcie->dev, sizeof(dma_addr_t), msi_vaddr, port->msg_addr);
irq_domain_remove(port->inner_domain);
return -ENOMEM;
}
@@ -518,10 +528,8 @@ static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
static void mtk_pcie_enable_msi(struct mtk_pcie_port *port)
{
u32 val;
- phys_addr_t msg_addr;

- msg_addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
- val = lower_32_bits(msg_addr);
+ val = lower_32_bits(port->msg_addr);
writel(val, port->base + PCIE_IMSI_ADDR);

val = readl(port->base + PCIE_INT_MASK);
@@ -588,7 +596,7 @@ static int mtk_pcie_init_irq_domain(struct mtk_pcie_port *port,
if (IS_ENABLED(CONFIG_PCI_MSI)) {
ret = mtk_pcie_allocate_msi_domains(port);
if (ret)
- return ret;
+ dev_warn(dev, "no MSI supported, only INTx available\n");
}

return 0;
@@ -732,7 +740,7 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
val &= ~INTX_MASK;
writel(val, port->base + PCIE_INT_MASK);

- if (IS_ENABLED(CONFIG_PCI_MSI))
+ if (IS_ENABLED(CONFIG_PCI_MSI) && port->msi_domain)
mtk_pcie_enable_msi(port);

/* Set AHB to PCIe translation windows */
--
2.18.0

2023-12-11 08:53:47

by Jianjun Wang (王建军)

[permalink] [raw]
Subject: [PATCH v2 2/3] PCI: mediatek-gen3: Do not break probe flow when MSI init fails

Since INTx can still work, the driver probe flow should not be broken by
MSI initialization failures. Additionally, moving the MSI initialization
code into a single function enhances readability.

Fixes: 1bdafba538be ("PCI: mediatek-gen3: Add MSI support")
Signed-off-by: Jianjun Wang <[email protected]>
---
drivers/pci/controller/pcie-mediatek-gen3.c | 68 ++++++++++-----------
1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
index c1ae3d19ec9a..c6a6876d233a 100644
--- a/drivers/pci/controller/pcie-mediatek-gen3.c
+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -649,59 +649,51 @@ static const struct irq_domain_ops intx_domain_ops = {
.map = mtk_pcie_intx_map,
};

-static int mtk_pcie_init_irq_domains(struct mtk_gen3_pcie *pcie)
+static int mtk_pcie_init_msi(struct mtk_gen3_pcie *pcie)
{
struct device *dev = pcie->dev;
- struct device_node *intc_node, *node = dev->of_node;
- int ret;
-
- raw_spin_lock_init(&pcie->irq_lock);
-
- /* Setup INTx */
- intc_node = of_get_child_by_name(node, "interrupt-controller");
- if (!intc_node) {
- dev_err(dev, "missing interrupt-controller node\n");
- return -ENODEV;
- }
-
- pcie->intx_domain = irq_domain_add_linear(intc_node, PCI_NUM_INTX,
- &intx_domain_ops, pcie);
- if (!pcie->intx_domain) {
- dev_err(dev, "failed to create INTx IRQ domain\n");
- ret = -ENODEV;
- goto out_put_node;
- }
+ struct device_node *node = dev->of_node;

- /* Setup MSI */
mutex_init(&pcie->lock);

pcie->msi_bottom_domain = irq_domain_add_linear(node, PCIE_MSI_IRQS_NUM,
&mtk_msi_bottom_domain_ops, pcie);
if (!pcie->msi_bottom_domain) {
dev_err(dev, "failed to create MSI bottom domain\n");
- ret = -ENODEV;
- goto err_msi_bottom_domain;
+ return -ENODEV;
}

- pcie->msi_domain = pci_msi_create_irq_domain(dev->fwnode,
- &mtk_msi_domain_info,
+ pcie->msi_domain = pci_msi_create_irq_domain(dev->fwnode, &mtk_msi_domain_info,
pcie->msi_bottom_domain);
if (!pcie->msi_domain) {
dev_err(dev, "failed to create MSI domain\n");
- ret = -ENODEV;
- goto err_msi_domain;
+ irq_domain_remove(pcie->msi_bottom_domain);
+ return -ENODEV;
}

- of_node_put(intc_node);
return 0;
+}

-err_msi_domain:
- irq_domain_remove(pcie->msi_bottom_domain);
-err_msi_bottom_domain:
- irq_domain_remove(pcie->intx_domain);
-out_put_node:
+static int mtk_pcie_init_intx(struct mtk_gen3_pcie *pcie)
+{
+ struct device *dev = pcie->dev;
+ struct device_node *intc_node, *node = dev->of_node;
+
+ intc_node = of_get_child_by_name(node, "interrupt-controller");
+ if (!intc_node) {
+ dev_err(dev, "missing interrupt-controller node\n");
+ return -ENODEV;
+ }
+
+ pcie->intx_domain = irq_domain_add_linear(intc_node, PCI_NUM_INTX,
+ &intx_domain_ops, pcie);
of_node_put(intc_node);
- return ret;
+ if (!pcie->intx_domain) {
+ dev_err(dev, "failed to create INTx IRQ domain\n");
+ return -ENODEV;
+ }
+
+ return 0;
}

static void mtk_pcie_irq_teardown(struct mtk_gen3_pcie *pcie)
@@ -774,10 +766,16 @@ static int mtk_pcie_setup_irq(struct mtk_gen3_pcie *pcie)
struct platform_device *pdev = to_platform_device(dev);
int err;

- err = mtk_pcie_init_irq_domains(pcie);
+ raw_spin_lock_init(&pcie->irq_lock);
+
+ err = mtk_pcie_init_intx(pcie);
if (err)
return err;

+ err = mtk_pcie_init_msi(pcie);
+ if (err)
+ dev_warn(dev, "no MSI supported, only INTx available\n");
+
pcie->irq = platform_get_irq(pdev, 0);
if (pcie->irq < 0)
return pcie->irq;
--
2.18.0

2024-06-08 09:07:35

by Manivannan Sadhasivam

[permalink] [raw]
Subject: Re: [PATCH v2 1/3] PCI: mediatek: Allocate MSI address with dmam_alloc_coherent()

On Mon, Dec 11, 2023 at 04:52:54PM +0800, Jianjun Wang wrote:
> Use dmam_alloc_coherent() to allocate the MSI address, instead of using
> virt_to_phys().
>

What is the reason for this change? So now PCIE_MSI_VECTOR becomes unused?

- Mani

> Signed-off-by: Jianjun Wang <[email protected]>
> ---
> drivers/pci/controller/pcie-mediatek.c | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index 66a8f73296fc..2fb9e44369f8 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
> @@ -178,6 +178,7 @@ struct mtk_pcie_soc {
> * @phy: pointer to PHY control block
> * @slot: port slot
> * @irq: GIC irq
> + * @msg_addr: MSI message address
> * @irq_domain: legacy INTx IRQ domain
> * @inner_domain: inner IRQ domain
> * @msi_domain: MSI IRQ domain
> @@ -198,6 +199,7 @@ struct mtk_pcie_port {
> struct phy *phy;
> u32 slot;
> int irq;
> + dma_addr_t msg_addr;
> struct irq_domain *irq_domain;
> struct irq_domain *inner_domain;
> struct irq_domain *msi_domain;
> @@ -394,12 +396,10 @@ static struct pci_ops mtk_pcie_ops_v2 = {
> static void mtk_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
> {
> struct mtk_pcie_port *port = irq_data_get_irq_chip_data(data);
> - phys_addr_t addr;
>
> /* MT2712/MT7622 only support 32-bit MSI addresses */
> - addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
> msg->address_hi = 0;
> - msg->address_lo = lower_32_bits(addr);
> + msg->address_lo = lower_32_bits(port->msg_addr);
>
> msg->data = data->hwirq;
>
> @@ -494,6 +494,14 @@ static struct msi_domain_info mtk_msi_domain_info = {
> static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
> {
> struct fwnode_handle *fwnode = of_node_to_fwnode(port->pcie->dev->of_node);
> + void *msi_vaddr;
> +
> + msi_vaddr = dmam_alloc_coherent(port->pcie->dev, sizeof(dma_addr_t), &port->msg_addr,
> + GFP_KERNEL);
> + if (!msi_vaddr) {
> + dev_err(port->pcie->dev, "failed to alloc and map MSI address\n");
> + return -ENOMEM;
> + }
>
> mutex_init(&port->lock);
>
> @@ -501,6 +509,7 @@ static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
> &msi_domain_ops, port);
> if (!port->inner_domain) {
> dev_err(port->pcie->dev, "failed to create IRQ domain\n");
> + dmam_free_coherent(port->pcie->dev, sizeof(dma_addr_t), msi_vaddr, port->msg_addr);
> return -ENOMEM;
> }
>
> @@ -508,6 +517,7 @@ static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
> port->inner_domain);
> if (!port->msi_domain) {
> dev_err(port->pcie->dev, "failed to create MSI domain\n");
> + dmam_free_coherent(port->pcie->dev, sizeof(dma_addr_t), msi_vaddr, port->msg_addr);
> irq_domain_remove(port->inner_domain);
> return -ENOMEM;
> }
> @@ -518,10 +528,8 @@ static int mtk_pcie_allocate_msi_domains(struct mtk_pcie_port *port)
> static void mtk_pcie_enable_msi(struct mtk_pcie_port *port)
> {
> u32 val;
> - phys_addr_t msg_addr;
>
> - msg_addr = virt_to_phys(port->base + PCIE_MSI_VECTOR);
> - val = lower_32_bits(msg_addr);
> + val = lower_32_bits(port->msg_addr);
> writel(val, port->base + PCIE_IMSI_ADDR);
>
> val = readl(port->base + PCIE_INT_MASK);
> @@ -588,7 +596,7 @@ static int mtk_pcie_init_irq_domain(struct mtk_pcie_port *port,
> if (IS_ENABLED(CONFIG_PCI_MSI)) {
> ret = mtk_pcie_allocate_msi_domains(port);
> if (ret)
> - return ret;
> + dev_warn(dev, "no MSI supported, only INTx available\n");
> }
>
> return 0;
> @@ -732,7 +740,7 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
> val &= ~INTX_MASK;
> writel(val, port->base + PCIE_INT_MASK);
>
> - if (IS_ENABLED(CONFIG_PCI_MSI))
> + if (IS_ENABLED(CONFIG_PCI_MSI) && port->msi_domain)
> mtk_pcie_enable_msi(port);
>
> /* Set AHB to PCIe translation windows */
> --
> 2.18.0
>
>

--
மணிவண்ணன் சதாசிவம்

2024-06-09 12:32:51

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH v2 1/3] PCI: mediatek: Allocate MSI address with dmam_alloc_coherent()

On Sat, 08 Jun 2024 10:01:52 +0100,
Manivannan Sadhasivam <[email protected]> wrote:
>
> On Mon, Dec 11, 2023 at 04:52:54PM +0800, Jianjun Wang wrote:
> > Use dmam_alloc_coherent() to allocate the MSI address, instead of using
> > virt_to_phys().
> >
>
> What is the reason for this change? So now PCIE_MSI_VECTOR becomes unused?

More importantly, this is yet another example of the DW reference
driver nonsense, where memory is allocated for *MSI*, while the whole
point of MSIs is that it is a write that doesn't target memory, making
any form of RAM allocation absolutely pointless.

This silly approach has been cargo-culted for years, and while I
caught a few in my time, you can't beat copy-paste.

IMO, this patch is only making things worse instead of fixing things.

M.

--
Without deviation from the norm, progress is not possible.

2024-06-11 17:23:59

by Bjorn Helgaas

[permalink] [raw]
Subject: Re: [PATCH v2 1/3] PCI: mediatek: Allocate MSI address with dmam_alloc_coherent()

On Sun, Jun 09, 2024 at 01:32:38PM +0100, Marc Zyngier wrote:
> On Sat, 08 Jun 2024 10:01:52 +0100,
> Manivannan Sadhasivam <[email protected]> wrote:
> >
> > On Mon, Dec 11, 2023 at 04:52:54PM +0800, Jianjun Wang wrote:
> > > Use dmam_alloc_coherent() to allocate the MSI address, instead of using
> > > virt_to_phys().
> >
> > What is the reason for this change? So now PCIE_MSI_VECTOR becomes unused?
>
> More importantly, this is yet another example of the DW reference
> driver nonsense, where memory is allocated for *MSI*, while the whole
> point of MSIs is that it is a write that doesn't target memory, making
> any form of RAM allocation absolutely pointless.
>
> This silly approach has been cargo-culted for years, and while I
> caught a few in my time, you can't beat copy-paste.
>
> IMO, this patch is only making things worse instead of fixing things.

Probably partly my fault. I think there are two pieces here:

1) allocating the MSI address
2) computing the PCI bus address

I don't know how to do 1), but I do encourage people not to use
virt_to_phys() for 2), since (in general) CPU physical addresses are
not the same as PCI bus addresses.