[PATCH v4 05/11] VAS: Define helpers for access MMIO regions

Sukadev Bhattiprolu
2017-03-31T05:14:20Z

Define some helper functions to access the MMIO regions. We use these
in a follow-on patches to read/write VAS hardware registers. These
helpers are also used to later issue 'paste' instructions to submit
requests to the NX hardware engines.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
---
Changelog [v3]:
- Minor reorg/cleanup of map/unmap functions

Changelog [v2]:
- Get HVWC, UWC and paste addresses from window->vinst (i.e DT)
rather than kernel macros.
---
arch/powerpc/platforms/powernv/vas-window.c | 126 ++++++++++++++++++++++++++++
1 file changed, 126 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 6156fbe..ec084d2 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -9,9 +9,135 @@

#include <linux/types.h>
#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/io.h>

#include "vas.h"

+/*
+ * Compute the paste address region for the window @window using the
+ * ->win_base_addr and ->win_id_shift we got from device tree.
+ */
+void compute_paste_address(struct vas_window *window, uint64_t *addr, int *len)
+{
+ uint64_t base, shift;
+ int winid;
+
+ base = window->vinst->win_base_addr;
+ shift = window->vinst->win_id_shift;
+ winid = window->winid;
+
+ *addr = base + (winid << shift);
+ *len = PAGE_SIZE;
+
+ pr_debug("Txwin #%d: Paste addr 0x%llx\n", winid, *addr);
+}
+
+static inline void get_hvwc_mmio_bar(struct vas_window *window,
+ uint64_t *start, int *len)
+{
+ uint64_t pbaddr;
+
+ pbaddr = window->vinst->hvwc_bar_start;
+ *start = pbaddr + window->winid * VAS_HVWC_SIZE;
+ *len = VAS_HVWC_SIZE;
+}
+
+static inline void get_uwc_mmio_bar(struct vas_window *window,
+ uint64_t *start, int *len)
+{
+ uint64_t pbaddr;
+
+ pbaddr = window->vinst->uwc_bar_start;
+ *start = pbaddr + window->winid * VAS_UWC_SIZE;
+ *len = VAS_UWC_SIZE;
+}
+
+static void *map_mmio_region(char *name, uint64_t start, int len)
+{
+ void *map;
+
+ if (!request_mem_region(start, len, name)) {
+ pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n",
+ __func__, start, len);
+ return NULL;
+ }
+
+ map = __ioremap(start, len, pgprot_val(pgprot_cached(__pgprot(0))));
+ if (!map) {
+ pr_devel("%s(): ioremap(0x%llx, %d) failed\n", __func__, start,
+ len);
+ return NULL;
+ }
+
+ return map;
+}
+
+/*
+ * Unmap the MMIO regions for a window.
+ */
+static void unmap_wc_paste_kaddr(struct vas_window *window)
+{
+ int len;
+ uint64_t busaddr_start;
+
+ if (window->paste_kaddr) {
+ iounmap(window->paste_kaddr);
+ compute_paste_address(window, &busaddr_start, &len);
+ release_mem_region((phys_addr_t)busaddr_start, len);
+ window->paste_kaddr = NULL;
+ }
+
+}
+
+static void unmap_wc_mmio_bars(struct vas_window *window)
+{
+ int len;
+ uint64_t busaddr_start;
+
+ unmap_wc_paste_kaddr(window);
+
+ if (window->hvwc_map) {
+ iounmap(window->hvwc_map);
+ get_hvwc_mmio_bar(window, &busaddr_start, &len);
+ release_mem_region((phys_addr_t)busaddr_start, len);
+ window->hvwc_map = NULL;
+ }
+
+ if (window->uwc_map) {
+ iounmap(window->uwc_map);
+ get_uwc_mmio_bar(window, &busaddr_start, &len);
+ release_mem_region((phys_addr_t)busaddr_start, len);
+ window->uwc_map = NULL;
+ }
+}
+
+/*
+ * Find the Hypervisor Window Context (HVWC) MMIO Base Address Region and the
+ * OS/User Window Context (UWC) MMIO Base Address Region for the given window.
+ * Map these bus addresses and save the mapped kernel addresses in @window.
+ */
+int map_wc_mmio_bars(struct vas_window *window)
+{
+ int len;
+ uint64_t start;
+
+ window->paste_kaddr = window->hvwc_map = window->uwc_map = NULL;
+
+ get_hvwc_mmio_bar(window, &start, &len);
+ window->hvwc_map = map_mmio_region("HVWCM_Window", start, len);
+
+ get_uwc_mmio_bar(window, &start, &len);
+ window->uwc_map = map_mmio_region("UWCM_Window", start, len);
+
+ if (!window->hvwc_map || !window->uwc_map) {
+ unmap_wc_mmio_bars(window);
+ return -1;
+ }
+
+ return 0;
+}
+
/* stub for now */
int vas_win_close(struct vas_window *window)
{
--
2.7.4