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Date: Tue, 8 Oct 2013 11:53:22 +0530
From: Kishon Vijay Abraham I <kishon@...com>
To: Jingoo Han <jg1.han@...sung.com>
CC: Bjorn Helgaas <bhelgaas@...gle.com>, <linux-pci@...r.kernel.org>,
<linux-samsung-soc@...r.kernel.org>,
Kukjin Kim <kgene.kim@...sung.com>,
Pratyush Anand <pratyush.anand@...com>,
Mohit KUMAR <Mohit.KUMAR@...com>,
Siva Reddy Kallam <siva.kallam@...sung.com>,
"'SRIKANTH TUMKUR SHIVANAND'" <ts.srikanth@...sung.com>,
Arnd Bergmann <arnd@...db.de>,
"'Sean Cross'" <xobs@...agi.com>,
"'Thierry Reding'" <thierry.reding@...il.com>,
"'Thomas Petazzoni'" <thomas.petazzoni@...e-electrons.com>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH V3] PCI: exynos: add support for MSI
Hi Jingoo,
On Friday 06 September 2013 12:24 PM, Jingoo Han wrote:
> This patch adds support for Message Signaled Interrupt in the
> Exynos PCIe diver using Synopsys designware PCIe core IP.
>
> Signed-off-by: Siva Reddy Kallam <siva.kallam@...sung.com>
> Signed-off-by: Srikanth T Shivanand <ts.srikanth@...sung.com>
> Signed-off-by: Jingoo Han <jg1.han@...sung.com>
> Cc: Pratyush Anand <pratyush.anand@...com>
> Cc: Mohit KUMAR <Mohit.KUMAR@...com>
> ---
> Changes since v2:
> - fixed MAX_MSI_CTRLS because MAX_MSI_IRQS is 32 only
> - used __get_free_pages() to allocate msi_data
> - used one msi_data and msi_irq_in_use per one RC
> - used irq_domain to represent the MSI controller
> - removed msi-base irq number from device tree because this is not
> a hardware property.
>
> Changes since v1:
> - removed unnecessary exynos_pcie_clear_irq_level()
> - updated the bindings documentation
> - used new msi_chip infrastructure
> - removed ARCH_SUPPORTS_MSI
> - replaced #ifdef guards with IS_ENABLED(CONFIG_PCI_MSI)
>
> drivers/pci/host/pci-exynos.c | 44 +++++++
> drivers/pci/host/pcie-designware.c | 240 ++++++++++++++++++++++++++++++++++++
> drivers/pci/host/pcie-designware.h | 14 +++
> 3 files changed, 298 insertions(+)
>
> diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-exynos.c
> index 94e096b..f062aca 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
> @@ -342,9 +343,36 @@ static irqreturn_t exynos_pcie_irq_handler(int irq, void *arg)
> return IRQ_HANDLED;
> }
>
> +static irqreturn_t exynos_pcie_msi_irq_handler(int irq, void *arg)
> +{
> + struct pcie_port *pp = arg;
> +
> + dw_handle_msi_irq(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);
> +
> + dw_pcie_msi_init(pp);
> +
> + /* enable MSI interrupt */
> + val = exynos_elb_readl(exynos_pcie, PCIE_IRQ_EN_LEVEL);
> + val |= IRQ_MSI_ENABLE;
> + exynos_elb_writel(exynos_pcie, val, PCIE_IRQ_EN_LEVEL);
> + return;
> +}
> +
> static void exynos_pcie_enable_interrupts(struct pcie_port *pp)
> {
> exynos_pcie_enable_irq_pulse(pp);
> +
> + if (IS_ENABLED(CONFIG_PCI_MSI))
> + exynos_pcie_msi_init(pp);
> +
> return;
> }
>
> @@ -430,6 +458,22 @@ static int add_pcie_port(struct pcie_port *pp, struct platform_device *pdev)
> return ret;
> }
>
> + if (IS_ENABLED(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;
> + }
> + }
> +
> 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 c10e9ac..8963017 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -11,8 +11,11 @@
> * published by the Free Software Foundation.
> */
>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.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>
> @@ -142,6 +145,204 @@ int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size,
> return ret;
> }
>
> +static struct irq_chip dw_msi_irq_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)
> +{
> + pp->msi_data = __get_free_pages(GFP_KERNEL, 0);
> +
> + /* program the msi_data */
> + dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4,
> + virt_to_phys((void *)pp->msi_data));
> + dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4, 0);
> +}
> +
> +static int find_valid_pos0(struct pcie_port *pp, int msgvec, int pos, int *pos0)
> +{
> + int flag = 1;
> +
> + do {
> + pos = find_next_zero_bit(pp->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;
> +}
> +
> +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(pp->msi_irq_in_use,
> + MAX_MSI_IRQS);
> + if (pos0 % no_irqs) {
> + if (find_valid_pos0(pp, no_irqs, pos0, &pos0))
> + goto no_valid_irq;
> + }
> + if (no_irqs > 1) {
> + pos1 = find_next_bit(pp->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(pp, no_irqs, pos1, &pos0))
> + goto no_valid_irq;
> + pos1 = find_next_bit(pp->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, pp->msi_irq_in_use);
> + irq_alloc_descs((irq + i), (irq + i), 1, 0);
> + irq_set_msi_desc(irq + i, desc);
> + /*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, pp->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);
> +}
> +
> +static int dw_msi_setup_irq(struct msi_chip *chip, 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_lo = virt_to_phys((void *)pp->msi_data);
> + msg.address_hi = 0x0;
> + msg.data = pos;
> + write_msi_msg(irq, &msg);
> +
> + return 0;
> +}
> +
> +static void dw_msi_teardown_irq(struct msi_chip *chip, unsigned int irq)
> +{
> + clear_irq(irq);
> +}
> +
> +static struct msi_chip dw_pcie_msi_chip = {
> + .setup_irq = dw_msi_setup_irq,
> + .teardown_irq = dw_msi_teardown_irq,
> +};
> +
> int dw_pcie_link_up(struct pcie_port *pp)
> {
> if (pp->ops->link_up)
> @@ -150,6 +351,20 @@ int dw_pcie_link_up(struct pcie_port *pp)
> return 0;
> }
>
> +static int dw_pcie_msi_map(struct irq_domain *domain, unsigned int irq,
> + irq_hw_number_t hwirq)
> +{
> + irq_set_chip_and_handler(irq, &dw_msi_irq_chip, handle_simple_irq);
> + irq_set_chip_data(irq, domain->host_data);
> + set_irq_flags(irq, IRQF_VALID);
> +
> + return 0;
> +}
> +
> +static const struct irq_domain_ops msi_domain_ops = {
> + .map = dw_pcie_msi_map,
> +};
> +
> int __init dw_pcie_host_init(struct pcie_port *pp)
> {
> struct device_node *np = pp->dev->of_node;
> @@ -157,6 +372,8 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
> struct of_pci_range_parser parser;
> u32 val;
>
> + struct irq_domain *irq_domain;
> +
> if (of_pci_range_parser_init(&parser, np)) {
> dev_err(pp->dev, "missing ranges property\n");
> return -EINVAL;
> @@ -223,6 +440,18 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
> return -EINVAL;
> }
>
> + if (IS_ENABLED(CONFIG_PCI_MSI)) {
> + irq_domain = irq_domain_add_linear(pp->dev->of_node,
> + MAX_MSI_IRQS, &msi_domain_ops,
> + &dw_pcie_msi_chip);
> + if (!irq_domain) {
> + dev_err(pp->dev, "irq domain init failed\n");
> + return -ENXIO;
> + }
> +
> + pp->msi_irq_start = irq_find_mapping(irq_domain, 0);
Where is the irq_create_mapping done for this irq domain? Is that not needed?
Without that I'm not getting the correct irq number.
Thanks
Kishon
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