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Subject[RFC PATCH 11/11] ppc: add dynamic dma window support
Date
If firmware allows us to map all of a partition's memory for DMA on a
particular bridge, create a 1:1 mapping of that memory. Add hooks for
dealing with hotplug events. Dyanmic DMA windows can use larger than the
default page size, and we use the largest one possible.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
---
arch/powerpc/platforms/pseries/iommu.c | 319 +++++++++++++++++++++++++++++++-
1 files changed, 315 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 451d2d1..23ca0d1 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -33,6 +33,7 @@
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/crash_dump.h>
+#include <linux/memory.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/rtas.h>
@@ -45,6 +46,7 @@
#include <asm/tce.h>
#include <asm/ppc-pci.h>
#include <asm/udbg.h>
+#include <asm/mmzone.h>

#include "plpar_wrappers.h"

@@ -278,10 +280,19 @@ struct dynamic_dma_window_prop {
__be32 window_shift; /* ilog2(tce_window_size) */
};

+struct direct_window {
+ struct device_node *device;
+ const struct dynamic_dma_window_prop *prop;
+ struct list_head list;
+};
+static LIST_HEAD(direct_window_list);
+static DEFINE_SPINLOCK(direct_window_list_lock);
+#define DIRECT64_PROPNAME "linux,direct64-ddr-window-info"
+
static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
- unsigned long num_pfn, void *arg)
+ unsigned long num_pfn, const void *arg)
{
- struct dynamic_dma_window_prop *maprange = arg;
+ const struct dynamic_dma_window_prop *maprange = arg;
int rc;
u64 tce_size, num_tce, dma_offset;
u32 tce_shift;
@@ -305,9 +316,9 @@ static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
}

static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
- unsigned long num_pfn, void *arg)
+ unsigned long num_pfn, const void *arg)
{
- struct dynamic_dma_window_prop *maprange = arg;
+ const struct dynamic_dma_window_prop *maprange = arg;
u64 *tcep, tce_size, num_tce, dma_offset, next, proto_tce;
u32 tce_shift;
long rc = 0;
@@ -368,6 +379,12 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
return rc;
}

+static int tce_setrange_multi_pSeriesLP_walk(unsigned long start_pfn,
+ unsigned long num_pfn, void *arg)
+{
+ return tce_setrange_multi_pSeriesLP(start_pfn, num_pfn, arg);
+}
+
#ifdef CONFIG_PCI
static void iommu_table_setparms(struct pci_controller *phb,
struct device_node *dn,
@@ -553,6 +570,246 @@ static void pci_dma_dev_setup_pSeries(struct pci_dev *dev)
pci_name(dev));
}

+/*
+ * If the PE supports dynamic dma windows, and there is space for a table
+ * that can map all pages in a linear offset, then setup such a table,
+ * and record the dma-offset in the struct device.
+ *
+ * dev: the pci device we are checking
+ * pdn: the parent pe node with the ibm,dma_window property
+ * Future: also check if we can remap the base window for our base page size
+ */
+static void check_ddr_windowLP(struct pci_dev *dev, struct device_node *pdn)
+{
+ int len, ret;
+ u32 query[4], create[3], cfg_addr;
+ int page_shift;
+ u64 dma_addr, buid, max_addr;
+ struct pci_dn *pcidn;
+ const u32 *uninitialized_var(ddr_avail);
+ struct direct_window *window;
+ struct property *uninitialized_var(win64);
+ struct dynamic_dma_window_prop *ddwprop;
+ const struct dynamic_dma_window_prop *direct64;
+
+ spin_lock(&direct_window_list_lock);
+
+ /* check if we already created a window */
+ list_for_each_entry(window, &direct_window_list, list) {
+ if (window->device == pdn) {
+ direct64 = window->prop;
+ goto set_device;
+ }
+ }
+ /* check if we kexec'd with a window */
+ direct64 = of_get_property(pdn, DIRECT64_PROPNAME, &len);
+ if (direct64)
+ goto create_window_listent;
+
+ ddr_avail = of_get_property(pdn, "ibm,ddw-applicable", &len);
+
+ if (!ddr_avail || len < 4 * sizeof(u32))
+ return;
+ /*
+ * the ibm,ddw-applicable property holds the tokens for:
+ * ibm,query-pe-dma-window
+ * ibm,create-pe-dma-window
+ * ibm,remove-pe-dma-window
+ * for the given node in that order.
+ *
+ * Query if there is a second window of size to map the
+ * whole partition. Query returns number of windows, largest
+ * block assigned to PE (partition endpoint), and two bitmasks
+ * of page sizes: supported and supported for migrate-dma.
+ */
+
+ /*
+ * Get the config address and phb build of the PE window.
+ * Rely on eeh to retrieve this for us.
+ * Retrieve them from the node with the dma window property.
+ */
+ pcidn = PCI_DN(pdn);
+ cfg_addr = pcidn->eeh_config_addr;
+ if (pcidn->eeh_pe_config_addr)
+ cfg_addr = pcidn->eeh_pe_config_addr;
+ buid = pcidn->phb->buid;
+ ret = rtas_call(ddr_avail[0], 3, 5, &query[0],
+ cfg_addr, BUID_HI(buid), BUID_LO(buid));
+ if (ret != 0) {
+ dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x"
+ " returned %d\n", ddr_avail[0], cfg_addr, BUID_HI(buid),
+ BUID_LO(buid), ret);
+ goto out_unlock;
+ }
+
+ if (!query[0]) {
+ /*
+ * no additional windows are available for this device.
+ * We might be able to reallocate the existing window,
+ * trading in for a larger page size.
+ */
+ dev_dbg(&dev->dev, "no free dynamic windows");
+ goto out_unlock;
+ }
+ if (query[2] & 4) {
+ page_shift = 24; /* 16MB */
+ } else if (query[2] & 2) {
+ page_shift = 16; /* 64kB */
+ } else if (query[2] & 1) {
+ page_shift = 12; /* 4kB */
+ } else {
+ dev_dbg(&dev->dev, "no supported direct page size in mask %x",
+ query[2]);
+ goto out_unlock;
+ }
+ /* verify the window * number of ptes will map the partition */
+ /* check largest block * page size > max memory hotplug addr */
+ max_addr = memory_hotplug_max();
+ if (query[1] < (max_addr >> page_shift)) {
+ dev_dbg(&dev->dev, "can't map partiton max 0x%llx with %u "
+ "%llu-sized pages\n", max_addr, query[1],
+ 1ULL << page_shift);
+ goto out_unlock;
+ }
+ len = order_base_2(max_addr);
+ win64 = kzalloc(sizeof(struct property), GFP_KERNEL);
+ if (!win64) {
+ dev_info(&dev->dev,
+ "couldn't allocate property for 64bit dma window\n");
+ goto out_unlock;
+ }
+ win64->name = kstrdup(DIRECT64_PROPNAME, GFP_KERNEL);
+ win64->value = ddwprop = kmalloc(sizeof(*ddwprop), GFP_KERNEL);
+ if (!win64->name || !win64->value) {
+ dev_info(&dev->dev,
+ "couldn't allocate property name and value\n");
+ goto out_free_prop;
+ }
+ do {
+ /* extra outputs are LIOBN and dma-addr (hi, lo) */
+ ret = rtas_call(ddr_avail[1], 7, 4, &create[0], cfg_addr,
+ BUID_HI(buid), BUID_LO(buid), len, page_shift);
+ } while(rtas_busy_delay(ret));
+ if (ret) {
+ dev_info(&dev->dev,
+ "failed to create direct window: rtas returned %d"
+ " to ibm,create-pe-dma-window(%x) %x %x %x %x %x\n",
+ ret, ddr_avail[1], cfg_addr, BUID_HI(buid),
+ BUID_LO(buid), len, page_shift);
+ goto out_free_prop;
+ }
+
+ *ddwprop = (struct dynamic_dma_window_prop) {
+ .liobn = cpu_to_be32(create[0]),
+ .dma_base = {cpu_to_be32(create[1]), cpu_to_be32(create[2])},
+ .tce_shift = cpu_to_be32(page_shift),
+ .window_shift = cpu_to_be32(len)
+ };
+
+ dev_dbg(&dev->dev, "created tce table LIOBN 0x%x for %s\n",
+ create[0], pdn->full_name);
+
+ ret = walk_system_ram_range(0, memblock_end_of_DRAM() >> PAGE_SHIFT,
+ win64->value, tce_setrange_multi_pSeriesLP_walk);
+ if (ret) {
+ dev_info(&dev->dev, "failed to map direct window for %s\n",
+ pdn->full_name);
+
+ goto out_clear_window;
+ }
+
+ ret = prom_add_property(pdn, win64);
+ if (ret) {
+ pr_err("%s: unable to add dma window property: %d",
+ pdn->full_name, ret);
+ goto out_clear_window;
+ }
+
+ direct64 = ddwprop;
+
+create_window_listent:
+ window = kzalloc(sizeof(*window), GFP_KERNEL);
+ if (!window)
+ goto out_clear_window;
+ window->device = pdn;
+ window->prop = direct64;
+ list_add(&window->list, &direct_window_list);
+
+set_device:
+ dma_addr = of_read_number(&direct64->dma_base[0], 2);
+ set_dma_offset(&dev->dev, dma_addr);
+ set_dma_ops(&dev->dev, &dma_choose64_ops);
+
+ dev_dbg(&dev->dev, "Can use direct dma at %s (offset %llx)\n",
+ pdn->full_name, dma_addr);
+
+out_unlock:
+ spin_unlock(&direct_window_list_lock);
+ return;
+
+out_clear_window:
+ ret = tce_clearrange_multi_pSeriesLP(0,
+ memblock_end_of_DRAM() >> PAGE_SHIFT, win64->value);
+ if (ret)
+ dev_info(&dev->dev,
+ "failed to clear partial window for %s\n",
+ pdn->full_name);
+
+ ret = rtas_call(ddr_avail[2], 1, 1, NULL, direct64->liobn);
+ if (ret) {
+ dev_info(&dev->dev,
+ "failed to remove direct window: rtas returned "
+ "%d to ibm,remove-pe-dma-window(%x) %x\n",
+ ret, ddr_avail[2], direct64->liobn);
+ }
+
+out_free_prop:
+ kfree(win64->name);
+ kfree(win64->value);
+ kfree(win64);
+
+ goto out_unlock;
+}
+
+#if 1 //def CLEAN_WINDOW_ON_REMOVE
+static void remove_ddr_windowLP(struct device_node *np)
+{
+ struct dynamic_dma_window_prop *dwp;
+ struct property *win64;
+ const u32 *ddr_avail;
+ int len, ret;
+
+ ddr_avail = of_get_property(np, "ibm,ddw-applicable", &len);
+
+ win64 = of_find_property(np, DIRECT64_PROPNAME, NULL);
+
+ if (!win64 || !ddr_avail || len < 4 * sizeof(u32))
+ return;
+
+ dwp = win64->value;
+
+ /* clear the whole window, note the arg is in kernel pages */
+ ret = tce_clearrange_multi_pSeriesLP(0,
+ 1ULL << (dwp->window_shift - PAGE_SHIFT), dwp);
+ if (ret)
+ pr_warning("%s failed to clear tces in window.\n",
+ np->full_name);
+
+ ret = rtas_call(ddr_avail[2], 1, 1, NULL, dwp->liobn);
+ if (ret)
+ pr_warning("%s: failed to remove direct window: rtas returned "
+ "%d to ibm,remove-pe-dma-window(%x) %x\n",
+ np->full_name, ret, ddr_avail[2], dwp->liobn);
+
+ ret = prom_remove_property(np, win64);
+ if (ret)
+ pr_warning("%s: failed to remove direct window property (%i)\n",
+ np->full_name, ret);
+}
+#else
+static void remove_ddr_windowLP(struct device_node *np) {}
+#endif
+
static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
{
struct device_node *pdn, *dn;
@@ -598,6 +855,7 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
}

set_iommu_table_base(&dev->dev, pci->iommu_table);
+ check_ddr_windowLP(dev, pdn);
}
#else /* CONFIG_PCI */
#define pci_dma_bus_setup_pSeries NULL
@@ -605,16 +863,68 @@ static void pci_dma_dev_setup_pSeriesLP(struct pci_dev *dev)
#define pci_dma_dev_setup_pSeriesLP NULL
#endif /* !CONFIG_PCI */

+static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
+ void *data)
+{
+ struct direct_window *window;
+ struct memory_notify *arg = data;
+ int ret = 0;
+
+ switch (action) {
+ case MEM_GOING_ONLINE:
+ spin_lock(&direct_window_list_lock);
+ list_for_each_entry(window, &direct_window_list, list) {
+ ret |= tce_setrange_multi_pSeriesLP(arg->start_pfn,
+ arg->nr_pages, window->prop);
+ /* XXX log error */
+ }
+ spin_unlock(&direct_window_list_lock);
+ break;
+ case MEM_CANCEL_ONLINE:
+ case MEM_OFFLINE:
+ spin_lock(&direct_window_list_lock);
+ list_for_each_entry(window, &direct_window_list, list) {
+ ret |= tce_clearrange_multi_pSeriesLP(arg->start_pfn,
+ arg->nr_pages, window->prop);
+ /* XXX log error */
+ }
+ spin_unlock(&direct_window_list_lock);
+ break;
+ default:
+ break;
+ }
+ if (ret && action != MEM_CANCEL_ONLINE)
+ return NOTIFY_BAD;
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block iommu_mem_nb = {
+ .notifier_call = iommu_mem_notifier,
+};
+
static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long action, void *node)
{
int err = NOTIFY_OK;
struct device_node *np = node;
struct pci_dn *pci = PCI_DN(np);
+ struct direct_window *window;

switch (action) {
case PSERIES_RECONFIG_REMOVE:
if (pci && pci->iommu_table)
iommu_free_table(pci->iommu_table, np->full_name);
+
+ spin_lock(&direct_window_list_lock);
+ list_for_each_entry(window, &direct_window_list, list) {
+ if (window->device == np) {
+ list_del(&window->list);
+ break;
+ }
+ }
+ spin_unlock(&direct_window_list_lock);
+
+ remove_ddr_windowLP(np);
break;
default:
err = NOTIFY_DONE;
@@ -653,6 +963,7 @@ void iommu_init_early_pSeries(void)


pSeries_reconfig_notifier_register(&iommu_reconfig_nb);
+ register_memory_notifier(&iommu_mem_nb);

set_pci_dma_ops(&dma_iommu_ops);
}
--
1.7.1


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