MIPS: SMTC: Support for Multi-threaded FPUs
Signed-off-by: Steven J. Hill <sjhill@mips.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3603/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c
index 15b5f3c..1d47843 100644
--- a/arch/mips/kernel/smtc.c
+++ b/arch/mips/kernel/smtc.c
@@ -86,6 +86,13 @@
static struct smtc_ipi_q freeIPIq;
+/*
+ * Number of FPU contexts for each VPE
+ */
+
+static int smtc_nconf1[MAX_SMTC_VPES];
+
+
/* Forward declarations */
void ipi_decode(struct smtc_ipi *);
@@ -174,9 +181,9 @@
__setup("tintq=", tintq);
-static int imstuckcount[2][8];
+static int imstuckcount[MAX_SMTC_VPES][8];
/* vpemask represents IM/IE bits of per-VPE Status registers, low-to-high */
-static int vpemask[2][8] = {
+static int vpemask[MAX_SMTC_VPES][8] = {
{0, 0, 1, 0, 0, 0, 0, 1},
{0, 0, 0, 0, 0, 0, 0, 1}
};
@@ -331,6 +338,22 @@
static void smtc_tc_setup(int vpe, int tc, int cpu)
{
+ static int cp1contexts[MAX_SMTC_VPES];
+
+ /*
+ * Make a local copy of the available FPU contexts in order
+ * to keep track of TCs that can have one.
+ */
+ if (tc == 1)
+ {
+ /*
+ * FIXME: Multi-core SMTC hasn't been tested and the
+ * maximum number of VPEs may change.
+ */
+ cp1contexts[0] = smtc_nconf1[0] - 1;
+ cp1contexts[1] = smtc_nconf1[1];
+ }
+
settc(tc);
write_tc_c0_tchalt(TCHALT_H);
mips_ihb();
@@ -343,22 +366,29 @@
* an active IPI queue.
*/
write_tc_c0_tccontext((sizeof(struct smtc_ipi_q) * cpu) << 16);
- /* Bind tc to vpe */
+
+ /* Bind TC to VPE. */
write_tc_c0_tcbind(vpe);
+
/* In general, all TCs should have the same cpu_data indications. */
memcpy(&cpu_data[cpu], &cpu_data[0], sizeof(struct cpuinfo_mips));
- /* For 34Kf, start with TC/CPU 0 as sole owner of single FPU context */
- if (cpu_data[0].cputype == CPU_34K ||
- cpu_data[0].cputype == CPU_1004K)
+
+ /* Check to see if there is a FPU context available for this TC. */
+ if (!cp1contexts[vpe])
cpu_data[cpu].options &= ~MIPS_CPU_FPU;
+ else
+ cp1contexts[vpe]--;
+
+ /* Store the TC and VPE into the cpu_data structure. */
cpu_data[cpu].vpe_id = vpe;
cpu_data[cpu].tc_id = tc;
- /* Multi-core SMTC hasn't been tested, but be prepared */
+
+ /* FIXME: Multi-core SMTC hasn't been tested, but be prepared. */
cpu_data[cpu].core = (read_vpe_c0_ebase() >> 1) & 0xff;
}
/*
- * Tweak to get Count registes in as close a sync as possible. The
+ * Tweak to get Count registers synced as closely as possible. The
* value seems good for 34K-class cores.
*/
@@ -466,6 +496,24 @@
smtc_configure_tlb();
for (tc = 0, vpe = 0 ; (vpe < nvpe) && (tc < ntc) ; vpe++) {
+ /* Get number of CP1 contexts for each VPE. */
+ if (tc == 0)
+ {
+ /*
+ * Do not call settc() for TC0 or the FPU context
+ * value will be incorrect. Besides, we know that
+ * we are TC0 anyway.
+ */
+ smtc_nconf1[0] = ((read_vpe_c0_vpeconf1() &
+ VPECONF1_NCP1) >> VPECONF1_NCP1_SHIFT);
+ if (nvpe == 2)
+ {
+ settc(1);
+ smtc_nconf1[1] = ((read_vpe_c0_vpeconf1() &
+ VPECONF1_NCP1) >> VPECONF1_NCP1_SHIFT);
+ settc(0);
+ }
+ }
if (tcpervpe[vpe] == 0)
continue;
if (vpe != 0)
@@ -479,6 +527,18 @@
*/
if (tc != 0) {
smtc_tc_setup(vpe, tc, cpu);
+ if (vpe != 0) {
+ /*
+ * Set MVP bit (possibly again). Do it
+ * here to catch CPUs that have no TCs
+ * bound to the VPE at reset. In that
+ * case, a TC must be bound to the VPE
+ * before we can set VPEControl[MVP]
+ */
+ write_vpe_c0_vpeconf0(
+ read_vpe_c0_vpeconf0() |
+ VPECONF0_MVP);
+ }
cpu++;
}
printk(" %d", tc);