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Subject[PATCH] PCI: exynos: add support for MSI
Date
This patch adds support for Message Signaled Interrupt in the
Exynops PCIe diver using Synopsys designware PCIe core IP.

Signed-off-by: Siva Reddy Kallam <siva.kallam@samsung.com>
Signed-off-by: Srikanth T Shivanand <ts.srikanth@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Cc: Pratyush Anand <pratyush.anand@st.com>
Cc: Mohit KUMAR <Mohit.KUMAR@st.com>
---
arch/arm/boot/dts/exynos5440.dtsi | 2 +
arch/arm/mach-exynos/Kconfig | 1 +
drivers/pci/host/pci-exynos.c | 60 ++++++++++
drivers/pci/host/pcie-designware.c | 213 ++++++++++++++++++++++++++++++++++++
drivers/pci/host/pcie-designware.h | 8 ++
5 files changed, 284 insertions(+)

diff --git a/arch/arm/boot/dts/exynos5440.dtsi b/arch/arm/boot/dts/exynos5440.dtsi
index 586134e..3746835 100644
--- a/arch/arm/boot/dts/exynos5440.dtsi
+++ b/arch/arm/boot/dts/exynos5440.dtsi
@@ -249,6 +249,7 @@
interrupt-map-mask = <0 0 0 0>;
interrupt-map = <0x0 0 &gic 53>;
num-lanes = <4>;
+ msi-base = <200>;
};

pcie@2a0000 {
@@ -269,5 +270,6 @@
interrupt-map-mask = <0 0 0 0>;
interrupt-map = <0x0 0 &gic 56>;
num-lanes = <4>;
+ msi-base = <232>;
};
};
diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 855d4a7..9ef1c95 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -93,6 +93,7 @@ config SOC_EXYNOS5440
default y
depends on ARCH_EXYNOS5
select ARCH_HAS_OPP
+ select ARCH_SUPPORTS_MSI
select HAVE_ARM_ARCH_TIMER
select AUTO_ZRELADDR
select MIGHT_HAVE_PCI
diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-exynos.c
index 012ca8a..d0477d0 100644
--- a/drivers/pci/host/pci-exynos.c
+++ b/drivers/pci/host/pci-exynos.c
@@ -48,6 +48,7 @@ struct exynos_pcie {
#define PCIE_IRQ_SPECIAL 0x008
#define PCIE_IRQ_EN_PULSE 0x00c
#define PCIE_IRQ_EN_LEVEL 0x010
+#define IRQ_MSI_ENABLE (0x1 << 2)
#define PCIE_IRQ_EN_SPECIAL 0x014
#define PCIE_PWR_RESET 0x018
#define PCIE_CORE_RESET 0x01c
@@ -320,9 +321,51 @@ static irqreturn_t exynos_pcie_irq_handler(int irq, void *arg)
return IRQ_HANDLED;
}

+#ifdef CONFIG_PCI_MSI
+static void exynos_pcie_clear_irq_level(struct pcie_port *pp)
+{
+ u32 val;
+ struct exynos_pcie *exynos_pcie = to_exynos_pcie(pp);
+ void __iomem *elbi_base = exynos_pcie->elbi_base;
+
+ val = readl(elbi_base + PCIE_IRQ_LEVEL);
+ writel(val, elbi_base + PCIE_IRQ_LEVEL);
+ return;
+}
+
+static irqreturn_t exynos_pcie_msi_irq_handler(int irq, void *arg)
+{
+ struct pcie_port *pp = arg;
+
+ /* handle msi irq */
+ dw_handle_msi_irq(pp);
+ exynos_pcie_clear_irq_level(pp);
+
+ return IRQ_HANDLED;
+}
+
+static void exynos_pcie_msi_init(struct pcie_port *pp)
+{
+ u32 val;
+ struct exynos_pcie *exynos_pcie = to_exynos_pcie(pp);
+ void __iomem *elbi_base = exynos_pcie->elbi_base;
+
+ dw_pcie_msi_init(pp);
+
+ /* enable MSI interrupt */
+ val = readl(elbi_base + PCIE_IRQ_EN_LEVEL);
+ val |= IRQ_MSI_ENABLE;
+ writel(val, elbi_base + PCIE_IRQ_EN_LEVEL);
+ return;
+}
+#endif
+
static void exynos_pcie_enable_interrupts(struct pcie_port *pp)
{
exynos_pcie_enable_irq_pulse(pp);
+#ifdef CONFIG_PCI_MSI
+ exynos_pcie_msi_init(pp);
+#endif
return;
}

@@ -408,6 +451,23 @@ static int add_pcie_port(struct pcie_port *pp, struct platform_device *pdev)
return ret;
}

+#ifdef CONFIG_PCI_MSI
+ pp->msi_irq = platform_get_irq(pdev, 0);
+
+ if (!pp->msi_irq) {
+ dev_err(&pdev->dev, "failed to get msi irq\n");
+ return -ENODEV;
+ }
+
+ ret = devm_request_irq(&pdev->dev, pp->msi_irq,
+ exynos_pcie_msi_irq_handler,
+ IRQF_SHARED, "exynos-pcie", pp);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request msi irq\n");
+ return ret;
+ }
+#endif
+
pp->root_bus_nr = -1;
pp->ops = &exynos_pcie_host_ops;

diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 77b0c25..5a47f11 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -11,8 +11,10 @@
* published by the Free Software Foundation.
*/

+#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/pci.h>
#include <linux/pci_regs.h>
@@ -62,6 +64,14 @@
#define PCIE_ATU_FUNC(x) (((x) & 0x7) << 16)
#define PCIE_ATU_UPPER_TARGET 0x91C

+#ifdef CONFIG_PCI_MSI
+#define MAX_MSI_IRQS 32
+#define MAX_MSI_CTRLS 8
+
+static unsigned int msi_data;
+static DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
+#endif
+
static struct hw_pci dw_pci;

unsigned long global_io_offset;
@@ -144,6 +154,202 @@ int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size,
return ret;
}

+#ifdef CONFIG_PCI_MSI
+static struct irq_chip dw_msi_chip = {
+ .name = "PCI-MSI",
+ .irq_enable = unmask_msi_irq,
+ .irq_disable = mask_msi_irq,
+ .irq_mask = mask_msi_irq,
+ .irq_unmask = unmask_msi_irq,
+};
+
+/* MSI int handler */
+void dw_handle_msi_irq(struct pcie_port *pp)
+{
+ unsigned long val;
+ int i, pos;
+
+ for (i = 0; i < MAX_MSI_CTRLS; i++) {
+ dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12, 4,
+ (u32 *)&val);
+ if (val) {
+ pos = 0;
+ while ((pos = find_next_bit(&val, 32, pos)) != 32) {
+ generic_handle_irq(pp->msi_irq_start
+ + (i * 32) + pos);
+ pos++;
+ }
+ }
+ dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + i * 12, 4, val);
+ }
+}
+
+void dw_pcie_msi_init(struct pcie_port *pp)
+{
+ /* program the msi_data */
+ dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4,
+ __virt_to_phys((u32)(&msi_data)));
+ dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, 0);
+}
+
+static int find_valid_pos0(int msgvec, int pos, int *pos0)
+{
+ int flag = 1;
+
+ do {
+ pos = find_next_zero_bit(msi_irq_in_use,
+ MAX_MSI_IRQS, pos);
+ /*if you have reached to the end then get out from here.*/
+ if (pos == MAX_MSI_IRQS)
+ return -ENOSPC;
+ /*
+ * Check if this position is at correct offset.nvec is always a
+ * power of two. pos0 must be nvec bit alligned.
+ */
+ if (pos % msgvec)
+ pos += msgvec - (pos % msgvec);
+ else
+ flag = 0;
+ } while (flag);
+
+ *pos0 = pos;
+ return 0;
+}
+
+/* Dynamic irq allocate and deallocation */
+static int assign_irq(int no_irqs, struct msi_desc *desc, int *pos)
+{
+ int res, bit, irq, pos0, pos1, i;
+ u32 val;
+ struct pcie_port *pp = sys_to_pcie(desc->dev->bus->sysdata);
+
+ if (!pp) {
+ BUG();
+ return -EINVAL;
+ }
+
+ pos0 = find_first_zero_bit(msi_irq_in_use,
+ MAX_MSI_IRQS);
+ if (pos0 % no_irqs) {
+ if (find_valid_pos0(no_irqs, pos0, &pos0))
+ goto no_valid_irq;
+ }
+ if (no_irqs > 1) {
+ pos1 = find_next_bit(msi_irq_in_use,
+ MAX_MSI_IRQS, pos0);
+ /* there must be nvec number of consecutive free bits */
+ while ((pos1 - pos0) < no_irqs) {
+ if (find_valid_pos0(no_irqs, pos1, &pos0))
+ goto no_valid_irq;
+ pos1 = find_next_bit(msi_irq_in_use,
+ MAX_MSI_IRQS, pos0);
+ }
+ }
+
+ irq = (pp->msi_irq_start + pos0);
+
+ if ((irq + no_irqs) > (pp->msi_irq_start + MAX_MSI_IRQS-1))
+ goto no_valid_irq;
+
+ i = 0;
+ while (i < no_irqs) {
+ set_bit(pos0 + i, msi_irq_in_use);
+ irq_alloc_descs((irq + i), (irq + i), 1, 0);
+ irq_set_msi_desc(irq + i, desc);
+ irq_set_chip_and_handler(irq + i, &dw_msi_chip,
+ handle_simple_irq);
+ set_irq_flags(irq + i, IRQF_VALID);
+ /*Enable corresponding interrupt in MSI interrupt controller */
+ res = ((pos0 + i) / 32) * 12;
+ bit = (pos0 + i) % 32;
+ dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, &val);
+ val |= 1 << bit;
+ dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, val);
+ i++;
+ }
+
+ *pos = pos0;
+ return irq;
+
+no_valid_irq:
+ *pos = pos0;
+ return -ENOSPC;
+}
+
+static void clear_irq(unsigned int irq)
+{
+ int res, bit, val, pos;
+ struct irq_desc *desc;
+ struct msi_desc *msi;
+ struct pcie_port *pp;
+
+ /* get the port structure */
+ desc = irq_to_desc(irq);
+ msi = irq_desc_get_msi_desc(desc);
+ pp = sys_to_pcie(msi->dev->bus->sysdata);
+ if (!pp) {
+ BUG();
+ return;
+ }
+
+ pos = irq - pp->msi_irq_start;
+
+ irq_free_desc(irq);
+
+ clear_bit(pos, msi_irq_in_use);
+
+ /* Disable corresponding interrupt on MSI interrupt controller */
+ res = (pos / 32) * 12;
+ bit = pos % 32;
+ dw_pcie_rd_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, &val);
+ val &= ~(1 << bit);
+ dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_ENABLE + res, 4, val);
+}
+
+int arch_setup_msi_irq(struct pci_dev *pdev, struct msi_desc *desc)
+{
+ int irq, pos, msgvec;
+ u16 msg_ctr;
+ struct msi_msg msg;
+ struct pcie_port *pp = sys_to_pcie(pdev->bus->sysdata);
+
+ if (!pp) {
+ BUG();
+ return -EINVAL;
+ }
+
+ pci_read_config_word(pdev, desc->msi_attrib.pos+PCI_MSI_FLAGS,
+ &msg_ctr);
+ msgvec = (msg_ctr&PCI_MSI_FLAGS_QSIZE) >> 4;
+ if (msgvec == 0)
+ msgvec = (msg_ctr & PCI_MSI_FLAGS_QMASK) >> 1;
+ if (msgvec > 5)
+ msgvec = 0;
+
+ irq = assign_irq((1 << msgvec), desc, &pos);
+ if (irq < 0)
+ return irq;
+
+ msg_ctr &= ~PCI_MSI_FLAGS_QSIZE;
+ msg_ctr |= msgvec << 4;
+ pci_write_config_word(pdev, desc->msi_attrib.pos + PCI_MSI_FLAGS,
+ msg_ctr);
+ desc->msi_attrib.multiple = msgvec;
+
+ msg.address_hi = 0x0;
+ msg.address_lo = __virt_to_phys((u32)(&msi_data));
+ msg.data = pos;
+ write_msi_msg(irq, &msg);
+
+ return 0;
+}
+
+void arch_teardown_msi_irq(unsigned int irq)
+{
+ clear_irq(irq);
+}
+#endif
+
int dw_pcie_link_up(struct pcie_port *pp)
{
if (pp->ops->link_up)
@@ -225,6 +431,13 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
return -EINVAL;
}

+#ifdef CONFIG_PCI_MSI
+ if (of_property_read_u32(np, "msi-base", &pp->msi_irq_start)) {
+ dev_err(pp->dev, "Failed to parse the number of lanes\n");
+ return -EINVAL;
+ }
+#endif
+
if (pp->ops->host_init)
pp->ops->host_init(pp);

diff --git a/drivers/pci/host/pcie-designware.h b/drivers/pci/host/pcie-designware.h
index 133820f..fcff10e 100644
--- a/drivers/pci/host/pcie-designware.h
+++ b/drivers/pci/host/pcie-designware.h
@@ -38,6 +38,10 @@ struct pcie_port {
int irq;
u32 lanes;
struct pcie_host_ops *ops;
+#ifdef CONFIG_PCI_MSI
+ int msi_irq;
+ int msi_irq_start;
+#endif
};

struct pcie_host_ops {
@@ -57,6 +61,10 @@ int cfg_read(void __iomem *addr, int where, int size, u32 *val);
int cfg_write(void __iomem *addr, int where, int size, u32 val);
int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size, u32 val);
int dw_pcie_rd_own_conf(struct pcie_port *pp, int where, int size, u32 *val);
+#ifdef CONFIG_PCI_MSI
+void dw_handle_msi_irq(struct pcie_port *pp);
+void dw_pcie_msi_init(struct pcie_port *pp);
+#endif
int dw_pcie_link_up(struct pcie_port *pp);
void dw_pcie_setup_rc(struct pcie_port *pp);
int dw_pcie_host_init(struct pcie_port *pp);
--
1.7.10.4



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