[PATCH v2 06/08] PCI: rcar: Add DMABOUNCE support

Magnus Damm
2014-02-18T02:10:33Z

Add DMABOUNCE support together with a local memory area for
all PCI devices hanging off this bridge. 4MiB of memory is
set aside for coherent allocations which is shared between
the on-chip OHCI and EHCI devices that are hanging off the
PCI bridge. With this patch the driver will work for all
CONFIG_VMSPLIT settings.

Signed-off-by: Magnus Damm <damm@opensource.se>
---

Changes since V1:
- Updated to fit on top of patches by Ben Dooks.
- Break out code into rcar_pci_init_bounce()

drivers/pci/host/Kconfig | 2
drivers/pci/host/pci-rcar-gen2.c | 269 +++++++++++++++++++++++++++++++++++++-
2 files changed, 268 insertions(+), 3 deletions(-)

--- 0001/drivers/pci/host/Kconfig
+++ work/drivers/pci/host/Kconfig 2014-02-13 10:52:48.000000000 +0900
@@ -28,6 +28,8 @@ config PCI_TEGRA
config PCI_RCAR_GEN2
bool "Renesas R-Car Gen2 Internal PCI controller"
depends on ARM && (ARCH_R8A7790 || ARCH_R8A7791 || COMPILE_TEST)
+ select GENERIC_ALLOCATOR
+ select DMABOUNCE
help
Say Y here if you want internal PCI support on R-Car Gen2 SoC.
There are 3 internal PCI controllers available with a single
--- 0008/drivers/pci/host/pci-rcar-gen2.c
+++ work/drivers/pci/host/pci-rcar-gen2.c 2014-02-13 11:12:38.000000000 +0900
@@ -15,11 +15,14 @@
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/notifier.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/sizes.h>
#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/genalloc.h>

/* AHB-PCI Bridge PCI communication registers */
#define RCAR_AHBPCI_PCICOM_OFFSET 0x800
@@ -100,6 +103,11 @@ struct rcar_pci_priv {
struct resource *cfg_res;
int irq;
unsigned long window_size;
+ u32 window_base;
+ struct notifier_block bus_notifier;
+ struct gen_pool *dma_pool;
+ unsigned long dma_size;
+ dma_addr_t dma_phys;
};

/* PCI configuration space operations */
@@ -278,8 +286,8 @@ static int __init rcar_pci_setup(int nr,
RCAR_PCI_ARBITER_PCIBP_MODE;
iowrite32(val, reg + RCAR_PCI_ARBITER_CTR_REG);

- /* PCI-AHB mapping: 0x40000000 base */
- iowrite32(0x40000000 | RCAR_PCIAHB_PREFETCH16,
+ /* PCI-AHB mapping: dynamic base */
+ iowrite32(priv->window_base | RCAR_PCIAHB_PREFETCH16,
reg + RCAR_PCIAHB_WIN1_CTR_REG);

/* AHB-PCI mapping: OHCI/EHCI registers */
@@ -290,7 +298,7 @@ static int __init rcar_pci_setup(int nr,
iowrite32(RCAR_AHBPCI_WIN1_HOST | RCAR_AHBPCI_WIN_CTR_CFG,
reg + RCAR_AHBPCI_WIN1_CTR_REG);
/* Set PCI-AHB Window1 address */
- iowrite32(0x40000000 | PCI_BASE_ADDRESS_MEM_PREFETCH,
+ iowrite32(priv->window_base | PCI_BASE_ADDRESS_MEM_PREFETCH,
reg + PCI_BASE_ADDRESS_1);
/* Set AHB-PCI bridge PCI communication area address */
val = priv->cfg_res->start + RCAR_AHBPCI_PCICOM_OFFSET;
@@ -322,6 +330,235 @@ static struct pci_ops rcar_pci_ops = {
.write = rcar_pci_write_config,
};

+static struct rcar_pci_priv *rcar_pci_dev_to_priv(struct device *dev)
+{
+ struct pci_sys_data *sys = to_pci_dev(dev)->sysdata;
+
+ return sys->private_data;
+}
+
+static void *rcar_pci_dma_alloc(struct device *dev, size_t size,
+ dma_addr_t *handle, gfp_t gfp,
+ struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return (void *)gen_pool_dma_alloc(p->dma_pool, size, handle);
+}
+
+static void rcar_pci_dma_free(struct device *dev, size_t size, void *cpu_addr,
+ dma_addr_t handle, struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ gen_pool_free(p->dma_pool, (unsigned long)cpu_addr, size);
+}
+
+static struct dma_map_ops rcar_pci_dma_ops_init = {
+ .alloc = rcar_pci_dma_alloc,
+ .free = rcar_pci_dma_free,
+};
+
+static int rcar_pci_dma_mmap(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size,
+ struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->mmap(p->dev, vma, cpu_addr,
+ dma_addr, size, attrs);
+}
+
+static int rcar_pci_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
+ void *cpu_addr, dma_addr_t handle,
+ size_t size, struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->get_sgtable(p->dev, sgt, cpu_addr,
+ handle, size, attrs);
+}
+
+static dma_addr_t rcar_pci_dma_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->map_page(p->dev, page, offset,
+ size, dir, attrs);
+}
+
+static void rcar_pci_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ get_dma_ops(p->dev)->unmap_page(p->dev, dma_handle, size, dir, attrs);
+}
+
+static int rcar_pci_dma_map_sg(struct device *dev, struct scatterlist *sg,
+ int nents, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->map_sg(p->dev, sg, nents, dir, attrs);
+}
+
+static void rcar_pci_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
+ int nents, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ get_dma_ops(p->dev)->unmap_sg(p->dev, sg, nents, dir, attrs);
+}
+
+static void rcar_pci_dma_sync_single_for_cpu(struct device *dev,
+ dma_addr_t dma_handle,
+ size_t size,
+ enum dma_data_direction dir)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ get_dma_ops(p->dev)->sync_single_for_cpu(p->dev, dma_handle,
+ size, dir);
+}
+
+static void rcar_pci_dma_sync_single_for_device(struct device *dev,
+ dma_addr_t dma_handle,
+ size_t size,
+ enum dma_data_direction dir)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ get_dma_ops(p->dev)->sync_single_for_device(p->dev, dma_handle,
+ size, dir);
+}
+
+static void rcar_pci_dma_sync_sg_for_cpu(struct device *dev,
+ struct scatterlist *sg,
+ int nents,
+ enum dma_data_direction dir)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ get_dma_ops(p->dev)->sync_sg_for_cpu(p->dev, sg, nents, dir);
+}
+
+static void rcar_pci_dma_sync_sg_for_device(struct device *dev,
+ struct scatterlist *sg,
+ int nents,
+ enum dma_data_direction dir)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ get_dma_ops(p->dev)->sync_sg_for_device(p->dev, sg, nents, dir);
+}
+
+static int rcar_pci_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->mapping_error(p->dev, dma_addr);
+}
+
+static int rcar_pci_dma_supported(struct device *dev, u64 mask)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->dma_supported(p->dev, mask);
+}
+
+static int rcar_pci_dma_set_dma_mask(struct device *dev, u64 mask)
+{
+ struct rcar_pci_priv *p = rcar_pci_dev_to_priv(dev);
+
+ return get_dma_ops(p->dev)->set_dma_mask(p->dev, mask);
+}
+
+static struct dma_map_ops rcar_pci_dma_ops = {
+ .alloc = rcar_pci_dma_alloc,
+ .free = rcar_pci_dma_free,
+ .mmap = rcar_pci_dma_mmap,
+ .get_sgtable = rcar_pci_dma_get_sgtable,
+ .map_page = rcar_pci_dma_map_page,
+ .unmap_page = rcar_pci_dma_unmap_page,
+ .map_sg = rcar_pci_dma_map_sg,
+ .unmap_sg = rcar_pci_dma_unmap_sg,
+ .sync_single_for_cpu = rcar_pci_dma_sync_single_for_cpu,
+ .sync_single_for_device = rcar_pci_dma_sync_single_for_device,
+ .sync_sg_for_cpu = rcar_pci_dma_sync_sg_for_cpu,
+ .sync_sg_for_device = rcar_pci_dma_sync_sg_for_device,
+ .mapping_error = rcar_pci_dma_mapping_error,
+ .dma_supported = rcar_pci_dma_supported,
+ .set_dma_mask = rcar_pci_dma_set_dma_mask,
+};
+
+static int rcar_pci_bus_notify(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct rcar_pci_priv *priv;
+ struct device *dev = data;
+ struct pci_dev *pci_dev = to_pci_dev(dev);
+ struct pci_sys_data *sys = pci_dev->sysdata;
+
+ priv = container_of(nb, struct rcar_pci_priv, bus_notifier);
+ if (priv != sys->private_data)
+ return 0;
+
+ if (action == BUS_NOTIFY_BIND_DRIVER)
+ set_dma_ops(dev, &rcar_pci_dma_ops);
+
+ return 0;
+}
+
+static void rcar_pci_add_bus(struct pci_bus *bus)
+{
+ struct pci_sys_data *sys = bus->sysdata;
+ struct rcar_pci_priv *priv = sys->private_data;
+
+ bus_register_notifier(&pci_bus_type, &priv->bus_notifier);
+}
+
+static void rcar_pci_remove_bus(struct pci_bus *bus)
+{
+ struct pci_sys_data *sys = bus->sysdata;
+ struct rcar_pci_priv *priv = sys->private_data;
+
+ bus_unregister_notifier(&pci_bus_type, &priv->bus_notifier);
+}
+
+static int rcar_pci_needs_bounce(struct device *dev,
+ dma_addr_t dma_addr, size_t size)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct rcar_pci_priv *priv = platform_get_drvdata(pdev);
+
+ if (dma_addr < priv->window_base)
+ return 1;
+
+ if (dma_addr >= (priv->window_base + priv->window_size))
+ return 1;
+
+ return 0;
+}
+
+static void rcar_pci_init_bounce(struct rcar_pci_priv *priv)
+{
+ /* use notifier to hook pool allocator */
+ priv->bus_notifier.notifier_call = rcar_pci_bus_notify;
+
+ /* setup alloc()/free() to let dmabounce allocate from our pool */
+ set_dma_ops(priv->dev, &rcar_pci_dma_ops_init);
+
+ /* shared dmabounce for the PCI bridge */
+ dmabounce_register_dev(priv->dev, 2048, 4096, rcar_pci_needs_bounce);
+}
+
static int rcar_pci_probe(struct platform_device *pdev)
{
struct resource *cfg_res, *mem_res;
@@ -329,6 +566,8 @@ static int rcar_pci_probe(struct platfor
void __iomem *reg;
struct hw_pci hw;
void *hw_private[1];
+ void *dma_virt;
+ int ret;

cfg_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
reg = devm_ioremap_resource(&pdev->dev, cfg_res);
@@ -358,6 +597,7 @@ static int rcar_pci_probe(struct platfor
priv->irq = platform_get_irq(pdev, 0);
priv->reg = reg;
priv->dev = &pdev->dev;
+ platform_set_drvdata(pdev, priv);

if (priv->irq < 0) {
dev_err(&pdev->dev, "no valid irq found\n");
@@ -365,6 +605,27 @@ static int rcar_pci_probe(struct platfor
}

priv->window_size = SZ_1G;
+ priv->dma_size = SZ_4M;
+
+ /* allocate pool of memory guaranteed to be inside window */
+ priv->dma_pool = devm_gen_pool_create(&pdev->dev, 7, -1);
+ if (!priv->dma_pool)
+ return -ENOMEM;
+
+ dma_virt = dmam_alloc_coherent(&pdev->dev, priv->dma_size,
+ &priv->dma_phys, GFP_KERNEL);
+ if (!dma_virt)
+ return -ENOMEM;
+
+ ret = gen_pool_add_virt(priv->dma_pool, (unsigned long)dma_virt,
+ priv->dma_phys, priv->dma_size, -1);
+ if (ret)
+ return ret;
+
+ /* select window base address based on physical address for memory */
+ priv->window_base = priv->dma_phys & ~(priv->window_size - 1);
+
+ rcar_pci_init_bounce(priv);

hw_private[0] = priv;
memset(&hw, 0, sizeof(hw));
@@ -373,6 +634,8 @@ static int rcar_pci_probe(struct platfor
hw.map_irq = rcar_pci_map_irq;
hw.ops = &rcar_pci_ops;
hw.setup = rcar_pci_setup;
+ hw.add_bus = rcar_pci_add_bus;
+ hw.remove_bus = rcar_pci_remove_bus;
pci_common_init_dev(&pdev->dev, &hw);
return 0;
}