On 29/01/2021 15.34, Pierre Morel wrote:
CSS characteristics exposes the features of the Channel SubSystem.
Let's use Store Channel Subsystem Characteristics to retrieve
the features of the CSS.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
lib/s390x/css.h | 57 +++++++++++++++++++++++++++++++++++++++++++++
lib/s390x/css_lib.c | 50 ++++++++++++++++++++++++++++++++++++++-
s390x/css.c | 12 ++++++++++
3 files changed, 118 insertions(+), 1 deletion(-)
diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index 3e57445..bc0530d 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -288,4 +288,61 @@ int css_residual_count(unsigned int schid);
void enable_io_isc(uint8_t isc);
int wait_and_check_io_completion(int schid);
+/*
+ * CHSC definitions
+ */
+struct chsc_header {
+ u16 len;
+ u16 code;
+};
+
+/* Store Channel Subsystem Characteristics */
+struct chsc_scsc {
+ struct chsc_header req;
+ u32 reserved1;
+ u32 reserved2;
+ u32 reserved3;
+ struct chsc_header res;
+ u32 format;
+ u64 general_char[255];
+ u64 chsc_char[254];
+};
+extern struct chsc_scsc *chsc_scsc;
+
+#define CSS_GENERAL_FEAT_BITLEN (255 * 64)
+#define CSS_CHSC_FEAT_BITLEN (254 * 64)
+
+int get_chsc_scsc(void);
+
+static inline int _chsc(void *p)
+{
+ int cc;
+
+ asm volatile(
+ " .insn rre,0xb25f0000,%2,0\n"
+ " ipm %0\n"
+ " srl %0,28\n"
+ : "=d" (cc), "=m" (p)
+ : "d" (p), "m" (p)
+ : "cc");
+
+ return cc;
+}
+
+#define CHSC_SCSC 0x0010
+#define CHSC_SCSC_LEN 0x0010
+
+static inline int chsc(void *p, uint16_t code, uint16_t len)
+{
+ struct chsc_header *h = p;
+
+ h->code = code;
+ h->len = len;
+ return _chsc(p);
+}
+
+#include <bitops.h>
+#define css_general_feature(bit) test_bit_inv(bit, chsc_scsc->general_char)
+#define css_chsc_feature(bit) test_bit_inv(bit, chsc_scsc->chsc_char)
+
#endif
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
index 3c24480..fe05021 100644
--- a/lib/s390x/css_lib.c
+++ b/lib/s390x/css_lib.c
@@ -15,11 +15,59 @@
#include <asm/arch_def.h>
#include <asm/time.h>
#include <asm/arch_def.h>
-
+#include <alloc_page.h>
#include <malloc_io.h>
#include <css.h>
static struct schib schib;
+struct chsc_scsc *chsc_scsc;
+
+int get_chsc_scsc(void)
+{
+ int i, n;
+ int ret = 0;
+ char buffer[510];
+ char *p;
+
+ report_prefix_push("Channel Subsystem Call");
+
+ if (chsc_scsc) {
+ report_info("chsc_scsc already initialized");
+ goto end;
+ }
+
+ chsc_scsc = alloc_pages(0);
+ report_info("scsc_scsc at: %016lx", (u64)chsc_scsc);
+ if (!chsc_scsc) {
+ ret = -1;
+ report(0, "could not allocate chsc_scsc page!");
+ goto end;
+ }
+
+ ret = chsc(chsc_scsc, CHSC_SCSC, CHSC_SCSC_LEN);
+ if (ret) {
+ report(0, "chsc: CC %d", ret);
+ goto end;
+ }
+
+ for (i = 0, p = buffer; i < CSS_GENERAL_FEAT_BITLEN; i++)
+ if (css_general_feature(i)) {
+ n = snprintf(p, sizeof(buffer) - ret, "%d,", i);
+ p += n;
+ }
+ report_info("General features: %s", buffer);
+
+ for (i = 0, p = buffer, ret = 0; i < CSS_CHSC_FEAT_BITLEN; i++)
+ if (css_chsc_feature(i)) {
+ n = snprintf(p, sizeof(buffer) - ret, "%d,", i);
+ p += n;
+ }
Please use curly braces for the for-loops here, too. Rationale: Kernel
coding style:
"Also, use braces when a loop contains more than a single simple statement"
Thanks,
Thomas
